Estratégias de adaptação à mudança climática opções de gestão de recursos hídricos para pequenos produtores

Estratégias de adaptação às mudanças climáticas: opções de gestão de recursos hídricos para sistemas de pequenos agricultores na África Subsaariana.

Este estudo avalia as estratégias apropriadas de gestão de recursos hídricos para pequenos agricultores na África Subsaariana, para garantir que a produção agrícola possa suportar os estresses causados ​​pelas mudanças climáticas. Ele identifica um conjunto de princípios para orientar as melhores estratégias e programas de gestão de recursos hídricos na África, incorporando sustentabilidade e desenvolvimento equitativo, estratégias de alocação de água, redução e diversificação de riscos e interações e compensações com objetivos ambientais e de saúde. Apela a uma maior atenção e investimento para melhorar a adaptação, especialmente por parte dos pequenos agricultores vulneráveis, e para maiores investimentos para apoiar a resiliência dos pequenos agricultores de lidar com as mudanças climáticas e a variabilidade.

O relatório está dividido em seis capítulos. O Capítulo 1 apresenta uma visão geral e antecedentes do problema, os objetivos do estudo e os resultados esperados. O Capítulo 2 concentra-se na metodologia do estudo, em particular na coleta e análise de dados, bem como no escopo do estudo. O Capítulo 3 inclui uma avaliação das tendências atuais e da experiência passada, com foco particular nos recursos hídricos e sua utilização na África. Uma revisão das estratégias de adaptação às mudanças climáticas é apresentada, bem como uma visão geral das práticas atuais em termos de projetos-piloto, agenda de pesquisa e intervenções de governança. O Capítulo 4 discute algumas das possíveis intervenções identificadas no Capítulo 3. O Capítulo 5 destaca as questões de governança, com ênfase nas políticas e estruturas institucionais existentes, e as reformas necessárias para melhorar a adaptação às mudanças climáticas. O Capítulo 6 resume as conclusões e recomendações do estudo.

Centro de Recursos para Adaptação às Mudanças Climáticas (ARC-X)

Estratégias para Adaptação às Mudanças Climáticas.

Explorar estratégias de adaptação.

Selecione uma aba abaixo para ver possíveis estratégias de adaptação para uma área específica de interesse ou explore uma lista de todas as estratégias de adaptação. Saiba mais sobre estratégias de adaptação.

As mudanças climáticas podem tornar mais difícil para as comunidades manter a qualidade do ar que protege a saúde humana e o meio ambiente. As Estratégias de Adaptação abaixo oferecem possíveis maneiras de abordar os riscos climáticos previstos para a qualidade do ar em ambientes externos e internos.

A mudança climática pode tornar mais difícil para as comunidades fornecer água potável e serviços de águas residuais, proteger a qualidade da água e manter ambientes aquáticos saudáveis. As Estratégias de Adaptação abaixo oferecem possíveis maneiras de abordar os riscos climáticos previstos para o gerenciamento da água.

As alterações climáticas podem dificultar a gestão adequada de resíduos perigosos e não perigosos. As páginas abaixo oferecem possíveis maneiras de abordar os riscos climáticos previstos para o gerenciamento de locais contaminados e o gerenciamento de detritos de desastres.

Saúde pública.

A mudança climática pode tornar mais difícil para as comunidades manter a saúde pública. As páginas abaixo oferecem possíveis maneiras de abordar os riscos de saúde pública para a qualidade do ar, a qualidade da água, o calor extremo e os problemas de resíduos relacionados às mudanças climáticas previstas.

Todas as estratégias.

A biorretenção é um recurso de paisagem adaptado que fornece armazenamento no local e a infiltração do escoamento de águas pluviais coletadas. O escoamento de águas pluviais é direcionado das superfícies para uma depressão rasa que permite que o escoamento suba antes da infiltração em uma área que é plantada com vegetação tolerante à água. À medida que o escoamento se acumula, ele irá se acumular e percorrer lentamente um leito de filtragem (foto à direita), onde se infiltra no solo ou é descarregado por meio de um sub-curso. Áreas de biorretenção em pequena escala são freqüentemente chamadas de jardins de chuva.

Um telhado azul é projetado para suportar até oito polegadas de precipitação em sua superfície ou em bandejas projetadas. É comparável a um telhado com vegetação sem solo ou vegetação. Após um evento de tempestade, a precipitação é armazenada no telhado e descarregada a uma taxa controlada. Os telhados azuis diminuem consideravelmente a descarga de pico do escoamento e também permitem que a água evapore no ar antes de serem descarregados.20 A descarga de precipitação é controlada em um telhado azul através de um dispositivo de restrição de fluxo ao redor de um dreno no telhado. A água pode ser liberada lentamente para um sistema de esgoto ou para outra prática gastrintestinal, como uma cisterna ou área de biorretenção.

O pavimento permeável inclui pavimentos e pavimentos com espaço vazio que permitem que o escoamento flua pelo pavimento (foto à esquerda). Uma vez que o escoamento flui através do pavimento, ele é temporariamente armazenado em uma base de pedra subterrânea antes de se infiltrar no solo ou descarregar de um dreno sob o mesmo. As pavimentadoras permeáveis ​​são altamente eficazes na remoção de metais pesados, óleos e graxa no escoamento. Pavimento permeável também remove nutrientes como fósforo e nitrogênio. O solo e o meio projetado filtram os poluentes à medida que o escoamento se infiltra através da superfície porosa. Os espaços vazios em superfícies de pavimento permeáveis ​​e camadas de reservatório fornecem capacidade de armazenamento para escoamento. Todos os sistemas de pavimento permeáveis ​​reduzem o volume de pico do escoamento.

Sistemas de armazenamento subterrâneo variam muito em design. Os sistemas de armazenamento subterrâneo detêm o escoamento em receptáculos subterrâneos que liberam lentamente o escoamento. Muitas vezes os receptáculos subterrâneos são bueiros, depósitos de detenção de águas pluviais modificadas ou canos perfurados. Um dos benefícios do armazenamento subterrâneo é que ele não ocupa uma área de superfície adicional e pode ser implementado embaixo de estradas, estacionamentos ou campos esportivos. Os sistemas de armazenamento subterrâneo são normalmente projetados para armazenar grandes volumes de escoamento e, portanto, podem ter um impacto significativo na redução de inundações e descargas de pico.

Uma trincheira de árvores de águas pluviais é uma fileira de árvores que é conectada por uma estrutura de infiltração subterrânea. No nível do solo, as árvores plantadas em uma trincheira de árvore não parecem diferentes de qualquer outra árvore plantada. Debaixo da calçada, as árvores ficam em uma trincheira que é projetada com camadas de cascalho e solo que armazenam e filtram o escoamento das águas pluviais. As trincheiras de árvores de águas pluviais proporcionam benefícios de redução da qualidade da água e do escoamento superficial.

Uma lagoa de retenção é um dos primeiros protótipos de IG, e agora é considerada um tipo mais tradicional de infraestrutura de águas pluviais porque foi integrada ao projeto de infraestrutura cinza. É uma bacia de águas pluviais projetada projetada para armazenar o escoamento e liberá-lo a uma taxa controlada, mantendo um nível de água com lagoas. Poluentes e cargas de sedimentos são reduzidos à medida que o escoamento é retido na bacia. As lagoas de retenção são uma prática muito comum de gerenciamento de águas pluviais e podem ser projetadas com elementos sustentáveis ​​para aumentar a qualidade da água e diminuir as descargas de pico. Foragays vegetais podem ser adicionados para aumentar a remoção de sedimentos, bem como fornecer habitat. Outro aprimoramento das lagoas de retenção de águas pluviais tradicionais é a adição de uma bancada de filtro de areia reforçada com ferro que remove substâncias dissolvidas, como o fósforo, do escoamento superficial.

Terras húmidas de detenção alargadas, como a mostrada na figura à direita, podem ser concebidas como uma estratégia de mitigação de inundações que também fornece benefícios ecológicos e de qualidade da água. Terras húmidas de detenção estendidas podem exigir grandes áreas de terra, mas vêm com benefícios significativos de armazenamento de inundação. Áreas úmidas de detenção estendidas podem ser criadas, restauradas (a partir de áreas úmidas previamente preenchidas) ou melhoradas as áreas úmidas existentes. Os pântanos normalmente armazenam a água da enchente durante uma tempestade e a liberam lentamente, reduzindo assim os fluxos de pico. Uma área úmida de detenção estendida permite que a água permaneça na área úmida por um longo período de tempo, o que proporciona maior armazenamento de enchentes e benefícios de qualidade da água.29 Áreas úmidas de detenção extensas são distintas da preservação de áreas úmidas existentes, mas as duas práticas são consideradas juntos como parte de uma estratégia baseada em bacias hidrográficas.

Fornecer treinamento para a equipe municipal sobre infraestrutura verde.

O treinamento pode ajudar a equipar melhor o pessoal para avaliar as propostas de infraestrutura verde. Por exemplo, a EPA oferece uma série de webcasts de infraestrutura verde. A EPA e outras agências federais e organizações não-governamentais formaram o Green Infrastructure Collaborative, uma rede para ajudar as comunidades a implementar com mais facilidade a infraestrutura verde.

A criação dessa lista pode ajudar a conectar profissionais experientes com projetos em potencial que poderiam se beneficiar de soluções de design alternativas.

Considere o uso ou o desenvolvimento de uma portaria modelo de águas pluviais para infraestrutura verde.

Essa portaria pode ajudar as jurisdições locais a incorporar projeções de mudanças climáticas ou incentivos de infraestrutura verde à legislação local. Por exemplo, a cidade de Seattle desenvolveu um decreto-modelo municipal para o gerenciamento de águas pluviais usando infraestrutura verde.

Conduza estudos piloto e publique os resultados e lições aprendidas para aumentar a conscientização e forneça exemplos específicos de como as soluções alternativas de gerenciamento de águas pluviais funcionam. Uma necessidade específica são exemplos adicionais que quantificam as taxas de infiltração em diferentes áreas para complementar o conhecimento existente.

Isso ajudará a complementar o conhecimento e o conhecimento da equipe existente.

Exemplos que abrangem uma série de municípios com diferentes orçamentos e populações são úteis para os profissionais locais encontrarem e consultarem estudos semelhantes às suas próprias comunidades.

(por exemplo, o que uma cidade gastou em reparos e substituição de infra-estrutura após uma tempestade; perdas de emprego e recreativas devido a infraestrutura danificada ou destruída) para facilitar uma melhor quantificação dos custos e benefícios dos investimentos em infraestrutura verde. Proporcionar oportunidades de compartilhamento de informações específicas para avaliação econômica. Webinars, workshops e ferramentas podem ser usados ​​para disseminar o conhecimento existente e responder a perguntas.

Treinar avaliadores / comissários locais para capturar o valor total da infraestrutura verde. Incorpore benefícios em cálculos de ROI, como serviços ecossistêmicos e fatores de qualidade de vida.

Isso pode incluir projetos em que a infraestrutura verde oferece um co-benefício com pouco ou nenhum custo adicional (por exemplo, o acesso à calçada compatível com o Americans with Disabilities Act [ADA], acrescentando um calçamento para proteção de pedestres que também coleta a água da chuva).

Desenvolva modelos que possam ser usados ​​para avaliar como diferentes métodos e projetos de infraestrutura verde podem funcionar em uma área e incluir orientações de estimativa de custos.

Desenvolver ferramentas para auxiliar na quantificação de custos e benefícios.

Atualize ou use as ferramentas existentes, incluindo a Calculadora Nacional de Águas Pluviais da EPA, a Calculadora Nacional de Gerenciamento de Águas Residuais de Green Valley do Center for Neighborhood Technology e o guia Value of Green Infrastructure.

Avaliar se a infraestrutura verde pode ser incluída como uma medida de controle em Sistemas de Esgoto Separados Municipais (MS4s). MS4s transportam o escoamento de águas pluviais que é frequentemente descarregado em corpos de água. Desde 1999, mesmo pequenas MS4s dentro e fora das áreas urbanizadas foram obrigadas a obter cobertura de permissão do Sistema Nacional de Eliminação de Descargas Poluidoras. Jurisdições com MS4s podem incluir infraestrutura verde como medida de controle. A EPA publicou uma ficha informativa que discute como a infraestrutura verde pode ser integrada às licenças de águas pluviais e fornece exemplos de comunidades que fizeram isso.

Coordenação entre agências federais, estaduais, locais e tribais Envolva todo o conjunto de agências e departamentos, particularmente no nível federal, que afetam ou poderiam ser afetados por soluções para lidar com as mudanças nas condições climáticas na gestão de águas pluviais. Considere envolver, por exemplo, a FEMA, o Corpo de Engenheiros do Exército, Departamentos de Transporte, Parques e Recreação e Departamentos de Estado de Ecologia ou Recursos Naturais. Incentive também uma política de "não há porta errada" (ou seja, que dados e informações sejam compartilhados em portais da Web e que os recursos sejam compartilhados entre as agências). Sete agências federais se uniram a organizações não-governamentais e entidades do setor privado para apoiar o Green Infrastructure Collaborative, uma rede para ajudar as comunidades a implementar com mais facilidade a infraestrutura verde.

A realocação de infraestrutura de serviços públicos, como estações de tratamento e estações de bombeamento, para elevações mais altas reduziria os riscos de inundação e exposição costeira como resultado da erosão costeira ou perda de zonas úmidas.

As barreiras de inundação para proteger a infraestrutura crítica incluem diques, diques e paredões. Uma estratégia relacionada é a proteção contra inundação, que envolve elevar o equipamento crítico ou colocá-lo em contêineres à prova d'água ou em sistemas de fundação.

O aumento da quantidade de armazenamento de água subterrânea disponível promove a recarga quando os fluxos de água superficiais excedem a demanda, aumentando assim a resiliência climática em períodos sazonais ou prolongados de seca e aproveitando as variações sazonais no escoamento de águas superficiais. Dependendo se a recarga natural ou artificial do aqüífero é empregada, a infraestrutura necessária pode incluir bacias de percolação e poços de injeção.

A diversificação de fontes ajuda a reduzir o risco de que o abastecimento de água caia abaixo da demanda de água. Exemplos de portfólios de água de fonte diversificada incluem o uso de uma mistura variada de águas superficiais e subterrâneas, empregando a dessalinização quando necessário e estabelecendo o comércio de água com outras empresas em tempos de escassez de água ou interrupção do serviço.

O aumento da seca pode reduzir o rendimento seguro dos reservatórios. Para reduzir esse risco, podem ser feitos aumentos no armazenamento disponível. Os métodos para isso podem incluir o levantamento de uma barragem, a prática de armazenamento e recuperação de aqüíferos, remoção de sedimentos acumulados em reservatórios ou redução da elevação da ingestão de água.

O aumento do nível do mar, combinado com as reduções no escoamento de água doce devido à seca, farão com que a fronteira entre a água salgada e a água doce se desloque mais para montante nos estuários das marés. As mudanças a montante deste limite podem reduzir a qualidade da água dos recursos hídricos superficiais. A instalação de represas de cabeça baixa em estuários de maré pode impedir esse movimento a montante.

As concessionárias de água são um dos principais consumidores de eletricidade nos Estados Unidos. Com a demanda futura de eletricidade prevista para crescer, pode ocorrer escassez de energia localizada. O desenvolvimento de fontes "fora da rede" pode ser uma boa estratégia de cobertura para déficits de eletricidade. Além disso, a fonte de alimentação redundante pode fornecer resiliência para situações em que desastres naturais causam interrupções de energia. As fontes no local podem incluir microturbinas solares, eólicas, em linha e biogás (ou seja, metano a partir do tratamento de águas residuais). Equipamentos elétricos novos e de reserva devem estar localizados acima dos níveis de inundação em potencial.

A reciclagem de água cinzenta libera mais água acabada para outros usos, ampliando o suprimento e diminuindo a necessidade de descarregar em águas receptoras. O recebimento de limitações na qualidade da água pode aumentar devido a secas mais freqüentes. Portanto, para limitar as descargas de águas residuais, o uso de água recuperada em residências e empresas deve ser incentivado.

As concessionárias de água são um dos principais consumidores de eletricidade nos Estados Unidos. Com a previsão de crescimento futuro da demanda por eletricidade, pode ocorrer uma escassez de energia localizada. As medidas de eficiência energética economizarão em custos de energia e tornarão as concessionárias menos vulneráveis ​​a déficits de eletricidade devido à alta demanda ou a interrupções de serviços decorrentes de desastres naturais.

O uso conjuntivo envolve o uso otimizado e coordenado da água superficial e subterrânea, tanto intra quanto interanual. O armazenamento e a recuperação de aqüíferos é uma forma de uso conjuntivo. Por exemplo, uma empresa de serviços públicos pode armazenar alguma fração dos fluxos de água de superfície nos aquíferos durante os anos úmidos e retirar essa água durante os anos secos, quando o fluxo do rio é baixo. Dependendo se a recarga natural ou artificial do aqüífero é empregada, a infraestrutura necessária pode incluir bacias de percolação e poços de injeção.

Um aumento na magnitude ou frequência de eventos extremos pode desafiar seriamente os sistemas de serviços de água que não foram projetados para suportar eventos intensos. Análises extremas de eventos ou modelagem podem ajudar a desenvolver uma melhor compreensão dos riscos e consequências associados a esses tipos de eventos.

A modelagem da dinâmica do aumento do nível do mar e do surto de tempestades informará melhor a colocação e a proteção da infraestrutura crítica. Modelos genéricos foram desenvolvidos para considerar subsidência, subida do nível do mar global e efeitos de tempestades na inundação, incluindo o modelo SLOSH (NOAA) da National Oceanic and Atmospheric Administration (Sea, Lake e Overland Surges from Hurricanes) e a ferramenta de resiliência costeira da The Nature Conservancy, entre outros.

Em muitas áreas, o aumento da temperatura da água causará a eutrofização e o crescimento excessivo de algas, o que reduzirá a qualidade da água potável. A qualidade das fontes de água potável também pode ser comprometida pelo aumento de entradas de sedimentos ou nutrientes devido a eventos extremos de tempestades. Esses impactos podem ser abordados com planos de manejo de bacias hidrográficas direcionados.

A compreensão e a modelagem das condições das águas subterrâneas informarão o gerenciamento do aqüífero e as mudanças projetadas na quantidade e qualidade da água. Dados de monitoramento do nível de água do aqüífero, mudanças na química e detecção de intrusão de água salgada podem ser incorporados em modelos para prever o fornecimento futuro. A mudança climática pode levar à diminuição da recarga das águas subterrâneas em algumas áreas, devido à redução da precipitação e diminuição do escoamento.

Eventos de tempestades mais extremos aumentarão a quantidade de infiltração em clima úmido e entrada em esgotos sanitários e combinados. Os modelos de esgoto podem estimar o impacto desses fluxos de clima úmido aumentado no sistema de coleta de águas residuais e na capacidade e operações da estação de tratamento. As possíveis modificações do sistema para reduzir esses impactos incluem medidas de redução de infiltração, capacidade adicional do sistema de coleta, armazenamento offline ou capacidade adicional de tratamento de clima úmido adicional.

A fim de entender como as mudanças climáticas podem afetar o futuro abastecimento de água e a qualidade da água, modelos hidrológicos, juntamente com projeções de modelos climáticos, devem ser desenvolvidos. É importante trabalhar para uma compreensão de como a distribuição média e temporal (sazonal) dos fluxos de águas superficiais pode mudar. A recarga de água subterrânea, a camada de neve e o momento do degelo são áreas críticas que podem ser severamente afetadas pelas mudanças climáticas e devem ser incorporadas à análise.

Ecossistemas naturais intactos trazem muitos benefícios para as concessionárias: reduzindo a entrada de sedimentos e nutrientes nos corpos hídricos fonte, regulando escoamento e vazão, protegendo contra enchentes e reduzindo impactos de tempestades e inundações nas costas (por exemplo, manguezais, pântanos de água salgada, zonas úmidas). As empresas de serviços públicos também podem trabalhar com gerentes regionais de várzea e partes interessadas apropriadas para explorar técnicas não estruturais de gestão de inundação na bacia hidrográfica. Proteger, adquirir e gerenciar ecossistemas em zonas de amortecimento ao longo de rios, lagos, reservatórios e costas pode ser uma medida custo-efetiva para o controle de enchentes e para a gestão da qualidade da água.

A infraestrutura verde pode ajudar a reduzir os fluxos de escoamento e águas pluviais que podem exceder a capacidade do sistema. Exemplos de infraestruturas verdes incluem: áreas de bio-retenção (jardins de chuva), métodos de desenvolvimento de baixo impacto, telhados verdes, depressões para captar água e o uso de vegetação ou materiais permeáveis ​​em vez de superfícies impermeáveis.

A gestão de bacias hidrográficas inclui uma série de medidas políticas e técnicas. Estes geralmente se concentram em preservar ou restaurar a cobertura vegetal da vegetação em uma bacia hidrográfica e gerenciar o escoamento de águas pluviais. Essas mudanças ajudam a imitar a hidrologia natural das bacias hidrográficas, aumentando a recarga das águas subterrâneas, reduzindo o escoamento e melhorando a qualidade do escoamento.

É fundamental que a futura infra-estrutura de serviços de água seja planejada e construída considerando os riscos futuros de inundação. A infraestrutura pode ser construída em áreas que não apresentam alto risco de inundações futuras. Alternativamente, podem ser implementados planos apropriados de gestão de inundações que envolvam medidas de adaptação “suaves”, como a conservação de ecossistemas naturais ou medidas “duras”, como diques e muros de inundação.

Terras húmidas costeiras atuam como amortecedores para a onda de tempestade. Proteger e entender a capacidade das zonas úmidas existentes de fornecer proteção para a infraestrutura costeira no futuro é importante, considerando a elevação projetada do nível do mar e possíveis mudanças na severidade da tempestade.

A freqüência e gravidade do incêndio podem mudar no futuro, portanto, é importante desenvolver, praticar e atualizar regularmente os planos de gerenciamento para reduzir o risco de incêndio. Queimaduras controladas, desbaste e ervas daninhas e controle de plantas invasivas ajudam a reduzir o risco em áreas propensas a incêndios florestais.

O setor elétrico retira a maior quantidade de água nos Estados Unidos, em comparação com outros setores. Quaisquer esforços para reduzir o uso de água pelas concessionárias (por exemplo, sistemas de circulação de água em circuito fechado ou resfriamento a seco para as turbinas) aumentarão o suprimento de água disponível. Por exemplo, as concessionárias podem fornecer água recuperada para as concessionárias de energia elétrica para geração de eletricidade.

A agricultura representa o segundo maior usuário de água nos Estados Unidos em termos de retiradas. A fim de prever e planejar as necessidades futuras de abastecimento de água, a demanda agrícola (irrigação) deve ser projetada, particularmente em áreas propensas à seca. Por exemplo, para reduzir a demanda de água agrícola, os serviços públicos podem trabalhar com os agricultores para adotar tecnologias avançadas de micro-irrigação (por exemplo, irrigação por gotejamento).

O setor elétrico representa o maior usuário de água nos Estados Unidos em termos de retiradas. Para prever as necessidades futuras de abastecimento de água, é necessário projetar mudanças na demanda de eletricidade relacionada à mudança climática.

Um método eficaz e de baixo custo de atender às necessidades crescentes de abastecimento de água é implementar programas de conservação de água que reduzirão o desperdício e a ineficiência. O alcance público é um componente essencial de qualquer programa de conservação de água. Comunicações de divulgação geralmente incluem: informações básicas sobre o uso doméstico de água, a melhor hora do dia para realizar atividades intensivas em água e informações sobre e acesso a utensílios domésticos eficientes como banheiros de baixo fluxo, chuveiros e lavadoras de carregamento frontal. Educação e divulgação também podem ser direcionados para diferentes setores (ou seja, comercial, institucional, industrial, setores públicos). Programas eficazes de conservação na comunidade incluem aqueles que fornecem descontos ou ajudam a instalar medidores de água, aparelhos de conservação de água, banheiros e tanques de coleta de água da chuva.

O aumento da temperatura da água na superfície pode exigir mudanças nos sistemas de tratamento de águas residuais, uma vez que as espécies microbianas utilizadas podem reagir de forma diferente em ambientes mais quentes. O teste de estresse envolve submeter sistemas biológicos ou simulações de sistemas de bancadas a temperaturas elevadas e monitorar os impactos nos processos de tratamento.

Mudanças no tempo de precipitação e escoamento, associadas a temperaturas mais altas devido a mudanças climáticas, podem levar à diminuição da qualidade da água do reservatório. A qualidade da água do reservatório pode ser mantida ou melhorada por meio de uma combinação de manejo de bacias hidrográficas, para reduzir o escoamento de poluentes e promover a recarga de água subterrânea e os métodos de gerenciamento do reservatório, como a aeração do lago.

O monitoramento é um componente crítico para estabelecer uma medida das condições atuais, detectar a deterioração dos ativos físicos e avaliar quando os ajustes necessários precisam ser feitos para prolongar a vida útil da infraestrutura.

Uma melhor compreensão das condições meteorológicas fornece a uma concessionária a capacidade de reconhecer possíveis mudanças na mudança climática e, em seguida, identificar a necessidade subsequente de alterar as operações atuais para garantir fornecimento e serviços resilientes. Observações de precipitação, temperatura e tempestades são particularmente importantes para melhorar os modelos de qualidade e quantidade de água projetada.

Entender e modelar as condições que resultam em inundações é uma parte importante da projeção de como a mudança climática pode gerar mudanças na ocorrência futura de enchentes. Os dados de monitoramento do nível do mar, precipitação, temperatura e escoamento podem ser incorporados nos modelos de inundação para melhorar as previsões. A magnitude de corrente de inundação e a frequência de eventos de tempestade representam uma linha de base para considerar possíveis condições futuras de inundação.

Entender as condições das águas superficiais e os fatores que alteram a quantidade e a qualidade é uma parte importante da projeção de como as mudanças climáticas podem afetar os recursos hídricos. Os dados de monitoramento para descarga, derretimento de neve, nível do reservatório ou da corrente, escoamento a montante, vazão de fluxo, temperatura in-stream e qualidade geral da água podem ser incorporados a modelos de fornecimento projetado ou de recebimento da qualidade da água.

Mudanças na vegetação alteram o escoamento que entra nos corpos hídricos superficiais e o risco de incêndios florestais para as instalações dentro da bacia hidrográfica. O monitoramento das mudanças na vegetação pode ser realizado por meio de pesquisas de cobertura do solo, fotografia aérea ou contando com a pesquisa de grupos de conservação locais e universidades.

Um seguro adequado pode isolar as empresas de perdas financeiras devido a eventos climáticos extremos, ajudando a manter a sustentabilidade financeira das operações da concessionária.

Um passo importante no desenvolvimento de um programa de adaptação é educar os funcionários sobre as mudanças climáticas. A equipe deve ter uma compreensão básica do intervalo projetado de mudanças na temperatura e precipitação, o aumento na frequência e magnitude de eventos climáticos extremos para sua região e como essas mudanças podem afetar os ativos e operações da concessionária. O preparo desse treinamento também pode melhorar o gerenciamento de serviços públicos nas condições climáticas atuais.

Os planos de restauração costeira podem proteger a infra-estrutura das empresas de serviços de água de danos causados ​​por tempestades, aumentando o habitat de proteção dos ecossistemas costeiros, como manguezais e zonas úmidas. Os planos de restauração devem considerar os impactos do aumento e desenvolvimento do nível do mar na distribuição futura do ecossistema. Estratégias bem-sucedidas também podem considerar a flexibilização de vagas e outras medidas identificadas pelo programa da EPA Climate Ready Estuaries.

Os planos de resposta a emergências (ERPs) descrevem as atividades e procedimentos que as concessionárias devem seguir em caso de um incidente, desde a preparação até a recuperação. Alguns dos eventos extremos considerados nos ERPs podem mudar em sua frequência ou magnitude devido a mudanças no clima, o que pode exigir mudanças nesses planos para capturar uma gama maior de possíveis eventos.

Os planos de gerenciamento de energia identificam os sistemas mais críticos em uma instalação, fornecem fontes de energia de backup para esses sistemas e avaliam opções para reduzir o consumo de energia, atualizando para equipamentos mais eficientes. As concessionárias podem desenvolver planos para produzir energia, reduzir o uso e trabalhar em direção a metas zero-zero.

Além do estabelecimento do comércio de água em tempos de escassez de água ou interrupções no serviço, esses acordos envolvem o compartilhamento de pessoal e recursos em tempos de emergência (por exemplo, desastres naturais).

Devem ser consideradas medidas operacionais para isolar e proteger os sistemas ou ativos mais vulneráveis ​​em uma empresa de serviços públicos. Por exemplo, as estações de bombeamento críticas incluiriam aquelas que servem uma grande população e aquelas localizadas em uma zona de inundação. A proteção desses ativos seria então priorizada com base na probabilidade de danos causados ​​pelas inundações e conseqüências da interrupção do serviço.

Os planos para construir ou expandir a infra-estrutura devem considerar a vulnerabilidade dos locais propostos a inundações no interior, elevação do nível do mar, tempestades e outros impactos associados à mudança climática.

Um planejamento de adaptação eficaz requer a cooperação e o envolvimento da comunidade. As concessionárias de água se beneficiarão envolvendo-se em esforços de planejamento de mudanças climáticas com governos locais e regionais, empresas de energia elétrica e outras organizações locais.

A seca leva a pressões severas no abastecimento de água. Os planos de contingência para seca incluiriam o uso de suprimentos alternativos de água e a adoção de restrições de uso de água para residências, empresas e outros usuários de água. Esses planos devem ser atualizados regularmente para permanecerem consistentes com as operações e ativos atuais.

Políticas pós-desastre devem minimizar a interrupção do serviço devido à infraestrutura danificada. Esses planos de contingência devem ser incorporados a outros esforços de planejamento e atualizados regularmente para permanecerem consistentes com quaisquer mudanças nos serviços ou ativos da concessionária.

À medida que o nível do mar aumenta, a água salgada pode invadir os aquíferos costeiros, resultando em custos de tratamento substancialmente mais elevados. A injeção de água doce nos aqüíferos pode ajudar a agir como uma barreira, enquanto a intrusão recarrega os recursos de água subterrânea.

O aumento do nível do mar e o aumento de tempestades costeiras podem causar o refluxo de esgotos. Para evitar isso, bombas mais fortes podem ser necessárias.

A variabilidade de precipitação aumentará em muitas áreas. Mesmo em áreas onde a precipitação e o escoamento podem diminuir em média, a distribuição dos padrões de precipitação (ou seja, intensidade e duração) pode mudar de forma a impactar a infraestrutura da água. Em particular, tempestades mais extremas podem sobrecarregar os sistemas combinados de esgoto e águas pluviais.

Os sistemas existentes de tratamento de água podem ser inadequados para processar água de qualidade significativamente reduzida. Melhorias significativas nos processos de tratamento existentes ou na implementação de tecnologias de tratamento adicionais podem ser necessárias para assegurar que a qualidade do suprimento de água (ou efluente) continue atendendo aos padrões, uma vez que a mudança climática impacta na fonte ou na recepção da qualidade da água.

Temperaturas superficiais mais altas podem dificultar o atendimento aos padrões de qualidade da água e aos critérios de temperatura. Portanto, para reduzir a temperatura das descargas de águas residuais tratadas, podem ser necessários sistemas adicionais de resfriamento de efluentes.

Em áreas onde a vazão da corrente diminui devido a mudanças climáticas, os níveis de água podem cair abaixo das tomadas de água para estações de tratamento de água.

Reúna conjuntos de dados existentes com informações como uso histórico da terra, desenvolvimento planejado, topografia e localização das várzeas. Eles geralmente são suficientes para sustentar uma conversa de curto prazo sobre como a gestão de águas pluviais pode precisar mudar para acomodar mudanças no clima. O uso da terra tem um tremendo efeito sobre os impactos das mudanças climáticas no manejo de águas pluviais; os gerentes podem incorporar mapas de mudança de uso da terra em discussões de planejamento. O projeto do Clima Integrado e Uso da Terra (ICLUS) da EPA pode servir como um recurso. Considere as atualizações das práticas de gerenciamento de dados para facilitar o uso dos melhores e mais recentes dados.

Use recursos para mostrar linhas de tendências históricas e futuras Para entender as mudanças climáticas futuras, técnicas que usam dados históricos, como eventos analógicos ou outras informações de sensibilidade e limiar no registro histórico, podem ser usadas como ilustrações (por exemplo, ver o IPCC [Painel Intergovernamental]. Mudanças Climáticas 2001: Grupo de Trabalho II: Impactos, Adaptação e Vulnerabilidade, Seção 3.5 O SWC da EPA e o SWMM-CAT fornecem projeções climáticas regionais reduzidas A EPA também está desenvolvendo uma aplicação web para visualizar e baixar a produção do modelo climático.

Sobre estratégias de adaptação.

As estratégias de adaptação fornecidas neste site destinam-se a informar e auxiliar as comunidades na identificação de possíveis alternativas. They are illustrative and are presented to help communities consider possible ways to address anticipated current and future threats resulting from the changing climate. In particular, it is important to note:

The strategies presented are NOT a comprehensive or exhaustive list of resiliency or adaptation actions that may be relevant. None of the provided alternatives are likely to be appropriate in all circumstances; the appropriateness of each alternative should be considered in the local context for which it is being considered. The potential strategies are largely drawn from EPA and other federal resources. Before adopting any particular strategy, it should be considered in the context provided by the primary source document from which it originated. Source document(s) are indicated. The presented strategies should not be relied on exclusively in conducting risk assessments, developing response plans, or making adaptation decisions. This information is not a substitute for the professional advice of an environmental or climate change professional or attorney.

Contact Us to ask a question, provide feedback, or report a problem.

The impact of climate change on smallholder and subsistence agriculture.

Edited by William Easterling, Pennsylvania State University, University Park, PA, and accepted by the Editorial Board September 26, 2007 (received for review March 2, 2007)

Some of the most important impacts of global climate change will be felt among the populations, predominantly in developing countries, referred to as “subsistence” or “smallholder” farmers. Their vulnerability to climate change comes both from being predominantly located in the tropics, and from various socioeconomic, demographic, and policy trends limiting their capacity to adapt to change. However, these impacts will be difficult to model or predict because of ( i ) the lack of standardised definitions of these sorts of farming system, and therefore of standard data above the national level, ( ii ) intrinsic characteristics of these systems, particularly their complexity, their location-specificity, and their integration of agricultural and nonagricultural livelihood strategies, and ( iii ) their vulnerability to a range of climate-related and other stressors. Some recent work relevant to these farming systems is reviewed, a conceptual framework for understanding the diverse forms of impacts in an integrated manner is proposed, and future research needs are identified.

Although both are widely used terms, there are surprisingly few published definitions of either “subsistence agriculture” or “smallholder agriculture.” Subsistence farming has been defined by Barnett et al. (1) as “farming and associated activities which together form a livelihood strategy where the main output is consumed directly, where there are few if any purchased inputs and where only a minor proportion of output is marketed.” However, the term is also sometimes used to denote the activity of self-provisioning with agricultural produce or a relative move toward such activity, as in developments in Eastern Europe following the end of the planned economies (2). It is also frequently used in a nontechnical sense to describe the rural poor of developing countries. † Such a usage diverts attention from the fact that market relations have entered deeply into agriculture in virtually all parts of the world, and that many of these farmers' most important problems stem from the terms of their inclusion in the market (3).

“Smallholder agriculture” is used more generally to describe rural producers, predominantly in developing countries, who farm using mainly family labor and for whom the farm provides the principal source of income (4). Definition of “peasants,” for example as given by Ellis (3), are similar but give more emphasis to inclusion in wider economic systems and imperfect markets. “Smallholder and subsistence farmers” is used here to denote these farmers, who can be found on a continuum between subsistence production and concentration on crop production for the market. Definitions by scale are relative to national contexts, and “smallholders” in transitional or developed countries may have farms (and incomes) many times larger than those in developing countries.

Pastoralists, who almost all depend on the sale of livestock and livestock products to buy staple foods and other necessities (5) and people dependent on artisanal fisheries and aquaculture enterprises (6) are also included in this category. All suffer, in varying degrees, similar problems associated with isolation and low levels of technology, but also unpredictable exposure to world markets.

These systems have been characterized as “complex, diverse and risk-prone” (7). Farms are generally small, often held under traditional or informal tenure, and are in marginal or risk-prone environments. Soil-related constraints to productivity are widespread, severe, and increasing (8), although diversity of soils and farmer soil management strategies is also important (9). Production systems are complex and diverse in the combinations of plant and animal species exploited, the types of integration between them, the production objectives and the institutional arrangements for managing natural resources. Risks (10) are also various—drought and flood, crop and animal disease, and market shocks—and may be felt by individual households or entire communities. Smallholder and subsistence farmers and pastoralists often practice hunting/gathering of wild resources as well as crop and livestock production to fulfil energy, clothing, health, and cash income needs as well as direct food requirements (11). They also widely participate in off-farm and/or nonfarm employment (12). Beyond these points, smallholder agriculture is subject to what has been called “the centrality of the social:” its grounding in social relations within households (particularly gender relations) and between households, profoundly affecting the negotiation of production decisions, management of knowledge, and marketing (13).

Given the lack of clear and standardized definitions of these categories, there are few informed estimates of world or regional population of smallholder or subsistence farmers (14). The United Nations Food and Agriculture Organization (FAO), for example, does not publish data disaggregated to these categories. Although not all smallholders, even in developing countries, are poor, data published by international agencies concerned with rural poverty give some idea of the scale of these livelihood systems. According to The International Fund for Agricultural Development (IFAD), 75% of the world's 1.2 billion poor (defined as consuming less than one purchasing-power adjusted dollar per day) live and work in rural areas (15). Earlier IFAD figures (16) suggest that ≈50% of the developing-country rural population were smallholders (farming 3 ha or less of crop land), and ≈25% were landless, which may have included some agricultural laborers, nonpastoralist livestock keepers, and poor people not engaged in agriculture. The proportion of smallholders in sub-Saharan Africa was higher at 73%. ‡ Smallholders are responsible for cultivating a hugely variable proportion of land across developing countries, with figures of >70% of arable and permanent cropland in several West and Southern African and Pacific countries. They are responsible in many countries for very high proportions of food and cash crop production, for example, 90% of rice, wheat, other food crops, cocoa, and cotton in Nigeria (16).

Non-Climate-Related Stressors and Trends.

Subsistence and smallholder livelihood systems currently experience a number of interlocking stressors, other than climate change and climate variability, as outlined in Table 1.

Nonclimate stressors affecting smallholder and subsistence agriculture.

The complex interaction of such stressors in increasing vulnerability can be illustrated with reference to pastoralists of the Horn of Africa and elsewhere. There are debates on whether environmental degradation in such tropical dryland areas is widespread, irreversible or appropriately referred to as “desertification” (25, 26), but there are, at the least, important processes of localized environmental degradation around small towns that are driven by the sedentarization of destitute pastoralists but also further weaken their livelihoods (27). Enclosure of land for farming by outsiders (28) and by pastoralists themselves (29) and demarcation of rangelands as Protected Areas has also been an issue: at the basis of all of these is a lack of government recognition of communal ownership of rangelands and traditional natural resource management (30). Human population increase, long neglected in pastoral studies, has been given new prominence by Sandford (31), who argues that its recognition, alongside other stressors, necessitates a major shift in views on pastoral development, with greater emphasis on diversification away from pastoralism and out-migration from the rangelands. Pastoralists are also subject to market-related stressors: the rapid withdrawal of government and parastatals from direct involvement in livestock purchasing and meat processing in Kenya in the 1980s is still lamented by Kenyan pastoralists (32). Although Horn of Africa pastoralists do not trade directly with Europe or North America, they are heavily involved in trade with Middle Eastern countries, in which they have been highly vulnerable to abrupt import bans on meat and livestock on veterinary grounds (33), in some cases with disputed scientific justification, but also seen as an indicator of a general trend to greater concern of Arab markets with meat quality and safety (34). Although there is a serious lack of information, but some concern, about the impact of HIV/AIDS on these pastoral populations (35), the impacts of armed conflicts, from international wars to quasitraditional raiding, on pastoralists throughout the region are now well known (36). All these, and other stressors, are seen as contributing to an increased vulnerability to drought, which in turn feeds back in to environmental degradation, conflict and underdevelopment of markets (37, 38).

However, all of the populations grouped as smallholder and subsistence farmers, including pastoralists and artisanal fisherfolk, also possess certain important resilience factors: efficiencies associated with the use of family labor (14), livelihood diversity allowing spreading of risks (12), and indigenous knowledge (39) allowing exploitation of risky environmental niches and coping with crises. The combinations of stressors and resilience factors give rise to complex positive and negative livelihood trends, envisaged differently by different authors, and depending largely on policy environments. Rural–urban migration will continue to be important; urban population growth in many large developing country cities is >4% per annum, and rural migrants account for between 35% and 60% of recorded urban population growth (40). Within rural areas, there will be continued diversification away from agriculture (41): nonfarm activities already account for 30–50% of rural income in developing countries (42). Although Vorley (43), Hazell (44), Lipton (14), and Toulmin and Gueye (45) see the possibility, given appropriate policies, of pro-poor growth based on the efficiency and employment generation associated with family farms, it is overall likely that smallholder and subsistence households will decline in numbers, as they are pulled or pushed into other livelihoods, with those that remain suffering increased vulnerability and increased poverty. The decline in numbers and qualitative changes in livelihoods mean that global and regional projections made for the category of smallholder and subsistence farmers will be progressively less meaningful over the medium - and long-term time scales associated with research and modeling on climate change.

Coping and Adaptation.

Smallholder, subsistence, and pastoral systems, especially those located in marginal environments, areas of high variability of rainfall or high risks of natural hazards, are often characterized by livelihood strategies that that have been evolved ( i ) to reduce overall vulnerability to climate shocks (“adaptive strategies”), and ( ii ) to manage their impacts ex-post (“coping strategies”). The distinction between these two categories is however frequently blurred (46): what start as coping strategies in exceptional years can become adaptations for households or whole communities.

Many defining features of dryland livelihoods in Africa and elsewhere can be regarded as adaptive strategies to climate variability. For example, Mortimore and Adams (47) for Northern Nigeria mention five major elements of adaptation:

Allocating farm labor across the season in ways that follow unpredictable intra-season rainfall variations: “negotiating the rain.”

Making use of biodiversity in cultivated crops and wild plants.

Increasing integration of livestock into farming systems (at a cost of increased labor demands).

Working land harder, in terms of labor input per hectare, without increasing external non-labor inputs.

Other authors have mentioned on-farm storage of food and feed, strategic use of fallow, and late planting of legume crops when cereals fail as drought responses—examples from rain-fed areas of Morocco (48).

African pastoralism has evolved in adaptation to harsh environments with very high spatial and temporal variability of rainfall (49). Several recent studies on Northern Kenya and Southern Ethiopia (50–53) reviewed by Morton (54) have focused on the coping strategies used by pastoralists during recent droughts and the longer-term adaptations that underlie them.

Mobility remains the most important pastoralist adaptation to spatial and temporal variations in rainfall, and in drought years many communities make use of fall-back grazing areas unused in “normal” dry seasons because of distance, land tenure constraints, animal disease problems, or conflict. However, encroachment on and individuation of communal grazing lands and the desire to settle to access human services and food aid have severely limited pastoral mobility.

Pastoralists engage in herd accumulation , and most evidence now suggests that this is a rational form of insurance against drought. There is considerable debate on the extent to which pastoralists cope by systematically selling livestock during drought or drought-onset, and why they might not do this, but some evidence that they would sell more stock if markets were more efficient.

Pastoralists classically keep multispecies herds to take advantage of different ecological niches and the labor of men, women, and children. Shifts in the balance of species can occur as responses to climate variability and changes in the environment, market conditions, and availability of labor.

A small proportion of pastoralists now hold some wealth in bank accounts, and others use informal savings and credit mechanisms through shopkeepers.

Pastoralists also use supplementary feed for livestock, purchased or lopped from trees, as a coping strategy, they intensify animal disease management through indigenous and scientific techniques, and they increasingly pay for water from powered boreholes.

Livelihood diversification away from pastoralism in this region predominantly takes the form of shifts into low-income or environmentally unsustainable occupations such as charcoal production, rather than an adaptive strategy to reduce ex-ante vulnerability.

There are a number of intracommunity mechanisms , to distribute both livestock products and the use of live animals to the destitute, but these appear to be breaking down due to high levels of covariate risk within communities.

Shifting to irrigated farming is sometimes seen as a coping strategy in the face of climate variability across the developing world. Eakin (55) describes this for Mexico, but notes that the interaction of market uncertainty with climatic risk may in fact increase the vulnerability of households making this shift. In South Asia, agricultural strategies such as increasing livestock production relative to crops, and selection of crop varieties, are responses to both drought and floods, but several case studies show the importance of livelihood diversification, in the villages and in towns, and both responsively to disaster and proactively (56). These and other studies also show the importance of information and networks or social capital in coping with climate change and variability (57).

The Impacts of Climate Change on Smallholder and Subsistence Agriculture.

Although there has been much recent public discussion of the effects of climate change on rural areas of developing countries, there has been little discussion that both engages with the science of climate change impact on agriculture, and with the specificities of smallholder and subsistence systems. Various tendencies are visible in the literature: firstly quantitative projections of future impacts from modeling studies, at a variety of geographical scales, focusing on key smallholder crops (58, 59) or ecosystems used by smallholder farmers (60), or reviewing data from such studies at a regional level (61). An important example is the work of Jones and Thornton (62), who find that aggregate yields of maize in smallholder rain-fed systems in Africa and Latin America are likely to show a decrease of ≈10% by 2055, but that these results hide enormous variability and give cause for concern, especially in some areas of subsistence agriculture. A development of this approach is that of ILRI (63), producing maps of vulnerability to climate change for sub-Saharan Africa, based on existing geographical data sets of current farming systems and of indicators of socioeconomic vulnerability, and projections of length of growing period, further differentiated by SRES scenario. This analysis highlights “hotspots” for vulnerability: semiarid mixed rain-fed crop-livestock systems in the Sahel, arid and semiarid grazing systems in East Africa and mixed crop-livestock and highland perennial crop systems in the Great Lakes Region.

A second tendency has focused on adaptation, often using qualitative data, and taking the characterization of impacts as a subsidiary and largely straightforward task (64, 65). Such work has often taken recent or current climate variability as a base on which to discuss adaptation, treating it largely as a proxy for future climate change, and some has emphasized the impacts of extreme events, such as tropical storms, which effect agriculture at a gross or landscape-level scale, as well as affecting livelihoods through destruction of housing and physical capital (61, 66).

A conceptual framework is now needed that can understand impacts of climate change on smallholder and subsistence agriculture (and related livelihoods like pastoralism and artisanal fishing) by harnessing the growing understanding of the biological processes involved in climate change impacts on crop and livestock production (67), to the specific features of these livelihoods.

Such a framework should.

recognize the complexity and high location-specificity of these production systems,

incorporate nonclimate stressors on rural livelihoods and their contribution to vulnerability, and.

study three different categories of climate change impact upon smallholder livelihoods:

Biological processes affecting crops and animals at the levels of individual organisms or fields;

Environmental and physical processes affecting production at a landscape, watershed or community level;

Impacts of climate change on human health and on nonagricultural livelihoods.

Complexity and Location Specificity.

Impacts on these systems should be considered in terms of hard to predict compound impacts highly specific to location and livelihood systems in different ecosystems and regions of the world. These livelihood systems are typically complex; they involve a number of crop and livestock species, between which there are interactions—for example, intercropping practices (39) or the use of draught animal power for cultivation (68), and potential substitutions such as alternative crops. Many smallholder livelihoods will also include use of wild resources (11), and nonagricultural strategies, such as use of remittances (12). Coping strategies for extreme climatic events such as drought (46–48, 54, 69) typically involve changes in the relative importance of crops, livestock species and nonagricultural activities, and in interactions between them. Positive and negative impacts on different crops may occur in the same farming system. Agrawala et al. (70) suggest that impacts on maize, the main food crop, will be strongly negative for the Tanzanian smallholder, whereas impacts on coffee and cotton, significant cash crops, may be positive.

Nonclimate Stressors and Vulnerability.

The intrinsic vulnerability of smallholder and subsistence farmers has been discussed above, as have the diverse powerful nonclimate stressors to which they are currently and increasingly subject. All these contribute to a very specific context of high vulnerability and limited adaptive capacity (65). Management of nonclimate stressors, such as poor market access, by governments and development donors, would itself constitute a powerful strategy for assisting adaptation, but some stressors, particularly various forms of environmental degradation, will themselves be influenced by climate change.

Approaches to mapping the combined vulnerability of rural populations to climate change and nonclimate stressors, have been explored for globalization by O'Brien and Leichenko (71) and for HIV/AIDS by Gommes et al. (72)

Biological Processes at Organism and Field Level.

Easterling et al. (67) and relevant articles in this volume show the growing understanding of the direct impacts of changes in temperature, CO 2 , and precipitation on yields of specific food and cash crops and productivity and health of livestock. In particular:

New syntheses of the growing number of regional and global simulation studies of changes in crop yields against temperature suggest that in the tropics, even moderate temperature increases (1–2°C) are likely to have negative impacts on yields of rice, maize, and wheat (the three major cereals worldwide and among smallholder and subsistence farmers). Higher levels of warming will have serious negative impacts on yields of maize and wheat, and less so on rice. Where simulations have included the effects of agronomic adaptation strategies, trends still represent declining yields at all levels of warming.

Increases in temperature may increase irrigation water requirements of major crops, increasing water stress, particularly in Southeast Asia.

The conclusion of the Third Assessment Report of the IPCC (73) of likely significant negative impacts on semiarid rangelands is confirmed, although there are still very few impact studies for tropical grasslands or rangelands. There is also new knowledge on the direct negative effects of thermal stress on productivity, conception rates and health of livestock, that may be relevant to exotic ( Bos taurus ) cattle kept for small-scale dairy production in the tropics (74).

There is evidence of increased risk of crop pests and diseases of crops under climate change, although knowledge of likely impacts in the tropics and on smallholder systems is much less developed. Modeling responses of both pathogens and (where relevant) insect vectors to rising temperatures and changing precipitation is complex, but there is cause for concern over possible spread of major diseases that attack smallholder crops in Africa: e. g., Maize Streak Virus and Cassava Mosaic Virus in areas where rainfall increases, and sorghum head smut (a fungal disease) in areas where rainfall decreases (which would be compounded by farmers switching adaptively to sorghum in areas where maize becomes marginal) (75). For diseases of livestock, modeling studies suggest overall slight declines in habitat suitable for tsetse-transmitted trypanosomiasis and East Coast Fever, although effects will be localized. Increased frequency of floods may increase outbreaks of epizootic diseases such as Rift Valley Fever and African Horse Sickness (76).

A general principle that crosscuts these projections of impacts on crops and livestock species is the increased understanding of the importance of extreme events (67). Increases in frequency of extreme events may go beyond the impacts of mean climate change in lowering long-term yields by damaging crops at particular developmental stages, making the timing of agricultural operations more difficult, and reducing incentives to cultivate (77). Increased frequency of heat waves and heavy precipitation events is regarded as very likely by IPCC Working Group 1 (78) and increased drought regarded as likely. Burke et al. (79) demonstrate the risk of widespread drought in many regions including Africa. Focus on extreme events in much of the literature on developing countries implicitly recognizes that their impacts are likely to be felt more strongly than the impacts of changing means in the medium-term (to 2025), a point made explicitly by Corbera et al. (80).

Environmental and Physical Processes.

Another class of impacts is felt at the level of communities, landscapes, and watersheds, and has been less considered in literature on climate change and agriculture, although there is some overlap with consideration given to extreme events. One such impact is the effects of decreasing snowcap on major irrigation systems involving hundreds of millions of smallholders, particularly in the Indo-Gangetic plain. As a result of warming, less precipitation falling as snow, and earlier spring melting, there will be a shift in peak water supply to winter and early spring and away from the summer months when irrigation is most needed, with likely severe effects in areas where storage capacity cannot be expanded (81). Combined with increased water demand, and preexisting vulnerability of many poorer irrigated farmers, such an impact could be catastrophic.

Also to be included here are effects of climate change on soil fertility and water-holding properties. Global warming and accompanying hydrological changes are likely to affect all soil processes in complex ways, including by accelerated decomposition of organic matter and depression of nitrogen-fixing activity (82). Kundzewicz et al. (83) note the projected increased erosivity of rainfall, and several factors likely to increase the erodibility of soils worldwide.

Other examples of such environmental or larger-scale impacts are the effects of sea level-rise on coastal areas, increased intensity of landfall tropical storms (78), and other forms of environmental impact still being identified, such as increased forest fire risk (70) for the Mount Kilimanjaro ecosystem and remobilization of dunes for semiarid Southern Africa (84).

Nonagricultural Climate Change Impacts.

The above impacts on agriculture will be combined with impacts on human health and ability to provide labor for agriculture, such as increased malaria risk (85), and on important secondary nonfarm livelihood strategies for many rural people in developing countries. One such strategy involves activities connected to tourism, and some negative impacts of climate change on tourism in developing countries have already been projected (86).

The above framework shows how complex and location-specific the projection of climate change impacts on smallholder and subsistence agriculture will be. A further complexity is given by the problem of distinguishing impact and adaptation. These systems are already characterized by constant adaptation to climate variability, which is forming the basis of adaptation to climate change: there will be profound methodological problems in observing or predicting impacts that do not also involve adaptation.

In general, however, the location of a large body of smallholder and subsistence farming households in the dryland tropics gives rise to especial concern over temperature-induced decline in crop yields, and increasing frequency and severity of drought. These lead to the following generalizations:

increased likelihood of crop failure;

increased diseases and mortality of livestock and/or forced sales of livestock at disadvantageous prices (37);

livelihood impacts including sale of other assets, indebtedness, out-migration and dependency on food relief.;

possible feedbacks through unsustainable adaptation strategies into environmental degradation including loss of biodiversity (87); e.

eventual impacts on human development indicators such as health and education.

Implications for Future Research Needs.

Understanding the interactions between the different forms of climate change impact will require further research on a variety of topics, and with a variety of approaches. One need is for modeling work based on a thorough understanding of the complexities of specific real-world smallholder systems. The multiagent modeling of Bharwani et al. is one possible approach here (88). Also important will be increased empirical research on the circumstances under which current strategies to cope with extreme events foster or constrain longer-term adaptation (46). Knowledge of crop responses to climate change also needs to be extended to more crops, livestock, and wild species of interest to smallholders and subsistence farmers, such as tropical rootcrops, sorghum and millet, beverage crops, backyard poultry and pigs, and acacia-based browse systems. A further need is for research on the impacts of climate change on the storage and marketing of smallholder crops: including losses to insect pests and pathogens of crops stored on-farm or by small traders, damage in transport (for example caused by deteriorated rural roads), and indirect costs of being less able to store on farm and more vulnerable to seasonal price swings.

Beyond these needs for research into impacts are needs for research into adaptation. Many of the potential agronomic adaptations identified (67), including improved soil and water conservation, are highly relevant to smallholder and subsistence systems, but require careful interdisciplinary and participatory research. The use of seasonal climate forecasting by smallholders needs to be carefully researched, with due emphases on farmers' ability to access, trust, and respond to forecasts (69, 89).

A further need is to broaden debate by more inclusion of literature from languages other than English, which has been markedly absent so far: the Africa chapter of the Report of the IPCC Working Group II (90), for example, contains only one non-Anglophone reference other than the official communications of Francophone governments to the United Nations Framework Convention on Climate Change (UNFCCC). This is only one aspect of a broader need to open up debates on impacts and adaptation to a wider range of stakeholders, including smallholder and subsistence farmers themselves.

Conclusão.

Smallholder and subsistence farmers will suffer impacts of climate change that will be locally specific and hard to predict. The variety of crop and livestock species produced by any one household and their interactions, and the importance of nonmarket relations in production and marketing, will increase the complexity both of the impacts and of subsequent adaptations, relative to commercial farms with more restricted ranges of crops. Small farm sizes, low technology, low capitalization, and diverse nonclimate stressors will tend to increase vulnerability, but the resilience factors—family labor, existing patterns of diversification away from agriculture, and possession of a store of indigenous knowledge—should not be underestimated.

Social-scientific study of the future impacts of climate change on poor rural people in developing countries has tended to be concerned with the increased frequency of extreme events with generalized impacts. This is understandable given the short to medium term importance of extreme events, and the difficulties of predicting any trends, climate-related or otherwise, in the longer term. However, there now must also be a genuinely interdisciplinary attempt to apply the rapidly growing scientific knowledge of the effects of climate change on crops and livestock to the “complex, diverse and risk-prone” farming systems of developing countries. This will not only improve knowledge of impacts, but just as important, aid in building adaptive capacity at all levels including that of farmers themselves.

*E-mail: j. f.morton gre. ac. uk.

Author contributions: J. F.M. designed research, performed research, analyzed data, and wrote the paper.

The author declares no conflict of interest.

This article is a PNAS Direct Submission. W. E. is a guest editor invited by the Editorial Board.

↵ † One suspects that it was in this sense that the Intergovernmental Panel on Climate Change mandated specific inclusion of “subsistence agriculture” in the Fourth Assessment Report.

↵ ‡ There appears to be some inconsistency between tables in the 1992 IFAD figures, but they do not significantly affect the argument here.

Climate Change Adaptation Strategies: Water Resources Management Options for Smallholder Farming Systems in Sub-Saharan Africa.

Climate change, population growth, increasing water demand, overexploitation of natural resources and environmental degradation have significantly degraded the world’s freshwater resources. In sub-Saharan Africa (SSA), the number of countries where water demand outstrips available resources is increasing. Many African countries experience either water stress (less than 1,700 m3 per capita per annum) or water scarcity (less than 1,000 m3 per capita per annum) or both. Moreover, food insecurity remains endemic throughout much of Africa, with climatic factors such as rainfall variability a major cause. For example, in 2006, 25 African countries required food aid, largely due to recurring drought. Poverty and food insecurity are linked to low agricultural productivity aggravated by climate change and variability. As 1970 Nobel Peace Prize Laureate Norman Borlaug stated, ‘Humankind in the 21st century will need to bring about a Blue Revolution to complement the Asian Green Revolution of the 20th century… New science and technology must lead the way.’…

Foresight For Development - Funding for this uniquely African foresight site was generously provided by Rockefeller Foundation. Email Us | Creative Commons Deed | Terms of Conditions.

Climate change adaptation strategies for smallholder farmers in the Brazilian Sertão.

Jennifer Burney Email author Daniele Cesano Jarrod Russell Emilio Lèvre La Rovere Thais Corral Nereide Segala Coelho Laise Santos.

Climate models agree that semi-arid regions around the world are likely to experience increased rainfall variability and longer droughts in the coming decades. In regions dependent on agriculture, such changes threaten to aggravate existing food insecurity and economic underdevelopment, and to push migration to urban areas. In the Brazilian semi-arid region, the Sertão, farmers’ vulnerability to climate—past, present, and future—stems from several factors, including low yielding production practices and reliance on scarce and seasonally variable water resources. Using interpolated local climate data, we show that, since 1962, in the Bacia do Jacuípe—one of the poorest regions in the Sertão of Bahía state—average temperatures have increased.

2 °C and rainfall has decreased.

350 mm. Over the same time period, average milk productivity—the main rural economic activity in the county—has fallen while in Brazil and in Bahía as a whole milk productivity has increased dramatically. This paper teases apart the drivers of climate vulnerability of the Bacia do Jacuípe in relation to the rest of Bahía. We then present the results of a suite of pilot projects by Adapta Sertão, a coalition of organizations working to improve the adaptive capacity of farmers living in the semi-arid region. By testing a number of different technologies and arrangements at the farm level, Adapta Sertão has shown that interventions focused on balanced animal diets and efficient irrigation systems can help reduce (but not eliminate) the dependence of production systems from climate. They are thus viable adaptation strategies that should be tested at a larger scale, with implications for semi-arid regions worldwide.

Electronic supplementary material.

The online version of this article (doi: 10.1007/s10584-014-1186-0 ) contains supplementary material, which is available to authorized users.

1 Importance of climate change for smallholder farmers.

Family farmers in Brazil are responsible for.

70 % of the food consumed by the Brazilian population (MDA 2012 ). At the same time, smallholder farmers 1 living in semi-arid Brazil are also considered the most vulnerable sector of Brazilian society to climate change impacts (Simões et al. 2010 ). These anticipated impacts range from reduced productivity to outmigration of labor due to increased economic strain (Lobell et al. 2008 ; Lobell et al. 2011 ; Assad et al. 2013 ).

Why are smallholder farmers vulnerable to climate change? No accepted consensus at present exists on the precise definitions of climate vulnerability, resilience, or adaptive capacity. The original ecological conception of resilience (Holling 1973 ) nevertheless applies here: a climate-resilient smallholder farming ecosystem is one in which farmers thrive even as baseline agroecologic conditions change. Conversely, a vulnerable system is one in which state changes in climate variables threaten the viability of smallholder farms. While farmers may have some degree of coping capacity (for example, assets that may be depleted in a given year to overcome a climate shock), their adaptive capacity—their ability to adjust to and thrive in changing conditions—is what drives resilience in the longer run (e. g., Berman et al. 2012 ).

Existing literature characterizes the vulnerability of Brazil’s smallholder farmers in the semi-arid northeast as a function of (a) the climate sensitivity of their production systems, (b) overall poverty levels (i. e., a lack of coping capacity), and (c) institutional weaknesses leading to a lack of overall adaptive capacity (e. g., Simões et al. 2010 ). On the physical side, climate models show enormous potential impact of future climate changes on the hydrology of the semi-arid region of Brazil, affecting river flow, water storage and irrigated production (Krol and Bronstert 2007 ; Silva et al. 2010 ). Models combined with hydrological observations from catchments in the area indicate the possibility of substantial reduction in surface water availability (Montenegro and Ragab 2012 ) and an ongoing process of environmental dryness (Rodrigues da Silva 2004 ). Indeed, integrated modeling studies show that water management is a key question for the development and sustainability of the semi-arid region of Brazil (e. g., Krol et al. 2006 ).

At the same time, farmers in the northeast region of Brazil are poor. This region received over 50 % of the national anti-poverty cash transfer program, “Bolsa Familia”, in 2011, despite representing only 25 % of the population (D’Andrade 2012 ). Overall service provision in the northeast is also low (IGBE 2006 ). As such, farmers in the area lack coping capacity. Perhaps most perversely, adaptation to climate change (including resiliency for smallholder farmers) is still most frequently discussed as though it is a far-off future need. As such, little has been done to build the adaptive capacity of farmers in the semi-arid region though targeted research and development and longer-run policies, or to create an integrated development and adaptation strategy for impoverished smallholder farmers (Simões et al. 2010 ).

In this paper, we ask four questions: (1) How has climate change in recent decades impacted land use and agricultural production in the semi-arid northeast? (2) What do these land use and productivity changes tell us about the vulnerability of farmers to climate change? (3) Among the technologies and interventions currently promoted by the government (at various levels), how can we quantify which effectively build adaptive capacity among smallholders? (4) Finally, how might results from tests of these technologies inform a more forward-looking, integrated development and adaptation policy environment in the northeast and in Brazil as a whole?

To answer these questions, the paper proceeds as follows: Section 2 describes the study context and methodology; Section 3 presents results from interpolated climate data at the municipality level, and teases apart the dynamics of climate vulnerability in the study region. Section 4 examines the results of several pilot tests of technologies meant to enhance climate resilience of smallholders and evaluates them in the context of regional vulnerability. Section 5 discusses these results in the climate vulnerability framework, and Section 6 offers policy lessons and conclusions to be drawn from the study.

2 Study design and methodology.

2.1 Study region.

900,000 km 2 and more than 20 million people. Public policy makers have long focused on the Sertão due to the poverty in the region. Regional economic and social indicators in the Brazilian semi-arid are well below the national average, with a yearly Gross Domestic Product (GDP) per capita of.

R$2,000 to R$3,000 ($1,000 to $1,500 USD), which is up to eight times lower than areas like the city of São Paulo, the industrial capital of Brazil (IBGE 2006 ). The Sertão is further characterized by a large imbalance in land ownership, and most of the impoverished are smallholder farmers. However, beyond structural economic disparities between small and large-scale farmers, the Sertão is subject to difficult environmental conditions. Average rainfall in the region is around 600 mm per year but varies tremendously over both time and space, with the variability making planning difficult for smallholders. The period from 2010 to 2013 featured the worst drought in 60 years, with devastating consequences on the local economy. Given that climate models agree on a number of likely future changes in the region—increased rainfall variability and drought, intensification of the hydrological deficit—understanding and addressing the adaptation possibilities for the region’s most vulnerable populations is critical.

Study Region. The Sertão ecoregion of Brazil, the state of Bahía, with the Bacia do Jacuípe (BDJ) in red . INMET weather stations closest to BDJ are indicated with blue dots . (See SI for a list of BDJ municipalities and INMET stations used in this analysis)

Our study focuses on the Bacia do Jacuípe county (hereafter BDJ), a territory within the Sertão in Bahía State that encompasses 14 contiguous municipalities over 10,612 km 2 (Fig. 1 ). BDJ is a predominantly agricultural area; Bahía is also an important agricultural state. Over the past several decades, however, the agricultural patterns of BDJ have changed and it has not shared in Bahía’s overall trend of increasing farm productivity. As such, it is an ideal location for understanding and characterizing smallholder climate vulnerability and for testing technologies and policies with potential to build resilience.

This work was conducted in conjunction with a local umbrella organization, Adapta Sertão. Adapta Sertão ( adaptasertao ) is a coalition of organizations created in 2006 to identify and test possible adaptation strategies for smallholder farmers, who otherwise lack funding and technical support, and to then implement and disseminate them across the region. The objective of Adapta Sertão is to create a community of NGOs, farmers’ cooperatives, and research and public policy institutions that foster long-term resilience for smallholder farmers. (Early work by the coalition has been described in Obermaier et al. 2009 and Simões et al. 2010 ; the organization is described in further detail in the Supporting Information. )

2.2 Methodology for climate trends detection.

As a first step to understanding regional climate vulnerability, we examined climate trends in BDJ over the past half-century. Climate data was sourced from weather stations owned and operated by Brazil’s National Meteorological Institute ( INMET ). Due to the absence of weather stations within BDJ (see Fig. 1 ), daily insolation, precipitation, and temperature data were interpolated from the 12 nearest-neighboring stations. Data were interpolated for each day between January 1, 1962 and December 31, 2012 and then aggregated over time and space for municipality and county level seasonal and annual statistics. In addition to average temperature and insolation metrics, and total precipitation indicators, we also examined rainfall intensity, using common rainfall rate (RR) indices to divide BDJ’s precipitation into five categories: dry days (RR = 0 mm), damp days (0 < RR ≤ 1 mm), wet days (RR > 1 mm), very wet days (RR ≥ 10 mm), and extremely wet days (RR ≥ 25 mm). In addition, we also calculated the maximum number of consecutive dry days each year (a measure of seasonal drought). Finally, beyond annual trends, we also examined trends for three rainy seasons in BDJ (identified empirically and corroborated in focus group interviews).

For the analysis from 1962 and 2012, years missing more than 10 % of daily data were intentionally excluded. Several of these years coincide with severe droughts during the first half of the 1980s and again in the early 1990s. The droughts reportedly caused INMET weather stations around BDJ to shut down, meaning this analysis omits some severe weather events due to insufficient data. However, a sensitivity analysis was performed to determine the effect of this data gap on the trends analysis; the missing years were shown to have an insignificant impact on the overall trends analysis of BDJ’s climate.

2.3 Methodology for adaptation technology testing.

Research in semi arid regions around the world has investigated several different technologies and strategies for coping with persistent droughts and hydrological stress. Water harvesting systems for supplemental irrigation, strategies to maximizing plant water availability and plant water uptake capacity, conservation tillage systems, storing excess crop harvests during good years, conservation agriculture, low-impact grazing strategies, use of drought resistant plants Leucaena leucocephala and Opuntia ficus-indica for fodder production and recession agriculture on the margins of reservoirs have all been shown to have at least some degree of success (Lima 1986 ; Rockström 2003 ; Archer 2004 ; Antonino et al. 2005 ; Dubeux et al. 2006 ; Jat et al. 2012 ; Mogotsi et al. 2013 ; Gutiérrez et al. 2014 ). The key challenge, however, remains in the identification of the most successful combination of possible strategies and technologies in a particular context and in its dissemination mechanism over a very large scale to reach the largest number of farmers. We conducted baseline surveys to identify candidate technologies to test.

In a survey of 350 smallholder farmers across BDJ, two clear patterns emerged that guided the choice of resiliency technologies. The first was underutilization of existing water resources. The survey revealed that local crop production in BDJ is almost entirely rain-fed (in the case of staples, mainly maize and cassava) or hand irrigated (vegetables): only 4 farmers out of the 350 surveyed were using irrigation equipment. Nevertheless, almost all farmers surveyed had access to at least one source of water, though these were most frequently ephemeral in nature (lasting up to 12 months maximum, but often dry for several months at a time). This underutilization of smallholder water management technologies persists in spite of the fact that, over the past half-century, the Brazilian government has constructed hundreds of small earth dams and wells to help with annual “smoothing” of seasonal water resources.

Second, the survey showed that average milk productivity in the region is 7 l/cow/day during the lactation period of the animal. Potential milk productivity is much higher; and this “yield gap” appears at least in part to be due to mismanaged feeding. Farmers report buying protein-enriched feed, like cotton or soy meal, with the hope of increasing milk productivity but they provide the animals with miscalculated quantities, mostly due to lack of information / technical assistance. The result is that farmers can give up to 300 % more protein than the animal needs, and often in an unbalanced way, which results in substantially lower milk productivity and reduced farm revenue. (A similar pattern was noted for meat production (goats), with farmers feeding animals a non-balanced diet and animals not growing as much as expected.)

Based on these patterns of farm activity throughout BDJ, Adapta Sertão conducted pilot tests of small-scale irrigation systems to improve food production, and of education on balanced animal feed practices to increase milk and meat productivity.

Irrigation.

Sixteen farmers using drip irrigation systems (out of 40 total) were selected and monitored regularly for a period of 2–5 years to understand the income, labor, and maintenance and operations costs—as well as the risks—associated with adoption of irrigation. Only eight of those farmers were able to use the system for more than 12 months continuously during that time due to water constraints (2010–2012 was a period of tremendous drought). Five of the farmers who stopped using an irrigation system during the pilot test did not have enough water to use it more than a few weeks per year; the remaining three farmers had access to water but decided it was not worthwhile to pursue irrigation on their own farms. Data from the continuous users, as well as preliminary diagnostics for predictors of successful use are presented in the results section below.

Milk production.

To conduct a pilot assessment of balanced animal feeding practices, Adapta Sertão performed a 2-month experiment with five different farmers. Three farmers separated some of their animals from their herd (6 cows the first farmer and one cow each for the second and third farmers) and fed them in confined settings (to monitor intake). In the first stage, farmers used their traditional feed for their animals. Technicians recorded milk production per animal, value of milk per liter, and cost of feed per kilogram over the course of 1 month. In the second stage, farmers fed them a diet optimized for voluminous roughage, energy, and protein for 1 month. Milk productivity on the new diet was compared to baseline.

Farmers in BDJ have two main breeds of dairy cattle—Sindi and Girolandia. Sindi are smaller animals, with peak production of.

10 l per animal per day under optimized diet; Girolandia are larger and can peak over.

20 l per animal per day with optimized diets. Baseline milk production in extensive systems (100 % pasture, no protein/energy complements) is around 2–5 l per cow per day. With some protein complements, the baseline rises to 5–7 l per animal per day. A typical baseline in BDJ, therefore, is assumed to be around 7 l per day; i. e., animals are being given some protein in addition to forage, but the ratio has not been optimized.

Meat production.

To test the impact of balanced feeding practices on meat production, a similar experiment was conducted with two farmers and 29 goats (10 and 19 goats from the two farms), comparing weight gain with a balanced diet to baseline feeding practices. Farmers fed the goats for 1 month as they had been before; in the second stage, each farmer was responsible for mixing the specified feed balance as dictated by the availability of the forage varieties grown on his or her property (e. g. prickly pear cactus, sorghum, etc.). The idea was to use all forage the farmer had available in his/her property and balance it with the right amount of protein and energy content. The use of protein - and energy-rich feeds purchased in local retailers (cotton and soy meal; corn) was necessary to balance the energy-protein-volume ratio. By using a comparison of before - and after-intervention data for each animal, potential benefits from the experiment were measured, including profitability and an understanding of carrying capacity of the farmers’ roughage production.

3 Historical climate changes and the dynamics of vulnerability in BDJ.

3.1 Climate trends.

Climate Trends in the Bacia do Jacuípe a 50-year average trends in temperature and precipitation in the Bacia do Jacuípe (BDJ), aggregated from interpolated INMET climate data. b Change in distribution of precipitation between 1962 and 2012. The number of wet days (>1 mm precipitation) has decreased, while the number of damp days (0–1 mm precipitation) has increased. This lack of nourishing rainfall translates into lower water availability on the ground. c 50-year temperature trends in BDJ, by municipality, °C/year fitted trend. d 50-year precipitation trends in BDJ, by municipality, mm/year. The entire BDJ region has experienced a strong and significant warming and drying trend over the past half-century. Data from INMET.

Comparisons of relative changes in precipitation and temperature across BDJ demonstrate commonalities and divergences between its 14 municipalities. All BDJ municipalities are getting drier and warmer, with a range of -5 to -10 mm in annual precipitation loss and 0.038 to 0.042 °C increase for average daily annual maximum temperature (Fig. 2c and d ).

3.2 Agricultural trends and dynamics of vulnerability.

Diagnosing climate vulnerability. Milk production and productivity in ( top ) Bahía and ( middle ) the Bacia do Jacuípe (BDJ) region over the past 4 decades. In 1974, Milk productivity (yield) in BDJ was higher than for Bahia as a whole. Over time, yield has fallen in BDJ but risen steadily in Bahia. In BDJ, production fails to recover after a large climate shock (1993). Milk production in Bahía as a whole suffers after that same climate shock, but more quickly recovers. ( bottom ) Year-to-year yield changes in BDJ are plotted with annual temperature and precipitation deviations from trend (e. g., Fig. 2a ). The dashed lines indicate +/− 1 standard deviation for precipitation (174 mm) and temperature (1.1 °C). Regression results showing the relationship between climate and milk productivity are presented in Table S1 . Data from IBGE and INMET.

As shown in Fig. 3 , such small-scale dairy farms can be very vulnerable to extreme climate events: in the severe drought of 1993, for example, all of Bahía suffered, with cattle dying and milk production dropping. Recovery took a number of years across the state. In BDJ, however, milk production was decimated: half of the cattle died, and milk production overall dropped by 75 %. Both the lack of productivity growth over time, and the disproportionate impact of the drought on BDJ indicate a lack of climate resiliency in BDJ vis-a-vis the rest of the state. Indeed, temperature and precipitation are statistically significant predictors of variations in overall yields and in year-to-year changes in yield (productivity per cow) between the municipalities of BDJ, but not for Bahia, over this time period (Fig. 3 , bottom, and SI Table 1 ).

This climate vulnerability has its roots in the dietary requirements of dairy cattle. Milk production depends on three variables in the cattle feed: overall volume (roughage), energetic (caloric) content, and protein content. Attempting to meet these constraints (particularly the volume requirement) on a small land footprint means that farmers are dependent on rainfall to promote forage growth, and reduced rainfall can easily lead to overgrazing and subsequent land compactification and degradation. Although Brazil legally requires all farmers to maintain 20 % of native habitat on their land undisturbed, enforcement is weak or nonexistent (Sparovek et al. 2010 ). And although agroforestry techniques that preserve trees and native habitat may lead to more productive grazing land in the long run, the incentive to overgraze exists in the short run, particularly in a bad (drought) year. In extreme years, farmers face a terrible choice between letting their cattle eat whatever they can and letting them die.

An examination of agricultural data ( IGBE ) over the past several decades in BDJ reveals several noteworthy trends. Area planted to corn and cassava (the main food and forage crops) has declined significantly in BDJ since 1990 (Figure S1 ). Although productivity (yield) has increased slightly over that time (overall production has remained essentially constant), these trends diverge from Bahía as a whole. Across the state, cassava area has remained fairly constant, with productivity rising slightly (similar to BDJ), but corn productivity in the state has increased dramatically (Figure S1b ). (Unfortunately, comprehensive crop production at the municipality level data do not exist prior to 1990.)

Land use and vulnerability. Land-use change in Brazil and BDJ. In the Sertão, much native Caatinga landscape has been converted to pastureland, driven by increased reliance on milk production for livelihoods. This deforestation exacerbates regional climate and low productivity problems. Data from Meiyappan and Jain ( 2012 )

It is difficult to pinpoint the exact cause of the wedge between productivity levels in Bahia as a whole (both crop and animal) and productivity levels in BDJ. However, we assume (in line with much of the literature on this type of divergence) that a relative lack of access (both in terms of physical proximity and economic means) to extension services, technical education, and productivity-enhancing technologies plays a leading role.

4 Testing technologies for climate adaptation in the Sertão.

Results from the irrigation pilot experiment, as well as the improved animal feed experiments for milk and meat production, are presented in Tables S2 , S3 , and S4 , respectively. (It should be noted that all tables contain monetary values in Brazilian Real (R$), with 1USD.

4.1 Smallholder irrigation.

Adapta Sertão’s irrigation pilot study financed small irrigation systems for 8 farmers and followed their progress for several years, from 2007 into the drought of 2010–2013. These are some of the longest detailed economic studies of irrigation systems with smallholder farmers available. Furthermore, farmers financed purchase of these systems through Adapta Sertão and were making loan repayments during the period of study. This differs dramatically from many existing studies that have examined impacts of efficient irrigation in the context of development projects where the equipment has been given to beneficiaries (e. g., Moyo et al. 2006 , Burney and Naylor 2012 ).

Table S2 presents the results of harmonized investment analysis on these systems. Physical details about the individual irrigation systems are given at the top of the table, followed by fixed and operating costs. Revenues include both the sale of products from the irrigated gardens and the value of produce consumed by the household. Profit is calculated in several ways: (1) total revenue minus total costs since installation; (2) average monthly profit, where the total profit is divided across the entire time period since installation; and (3) average monthly profit across operational months, where the total profit is divided only among months where the system was being used. Net Present Value (NPV) and Internal Rate of Return (IRR) are calculated over a 5 year time period. Finally, we include labor analysis where we document the total labor, and the portion of that labor by the system owner. We then calculate the returns to that labor (R$/h).

As shown in Table S2 , the systems studied varied in size and technology, although all were 1 ha or smaller. Size and system geometry were determined in consultation with each farmer, taking into account land layout, water source, and desired crops. In this study, the farmers produced a variety of vegetables and other crops using these systems, and chose when and how to operate them. Data for investment analysis were gathered during technician visits to the farms. Most of the systems were profitable, and significantly so, even when not including the value of work for the farmer. The median internal rate of return was 53 %. During the period farmers were using the systems, their income was comparable with the average local salary in the region outside farming (i. e. school teacher, social servant, etc.), when including the opportunity cost of mechanical water pumping.

Farmers with irrigation were able to produce, consume, and sell much more food than the period without irrigation (see revenues in Table S1 ). It is worth noting that farmers were selling a large percentage of their cultivated products, keeping an average of 16 % (by value) for home consumption. These numbers agree with previous detailed studies of irrigated vegetables production in developing semi-arid communities (e. g., Burney et al. 2010 ). Farmers also reported substantial livelihood improvement as they ceased to spend up to 4 h per day in fetching water. The majority of the farmers were engaged in irrigated vegetable production as a part-time activity (behind milk/meat production), but of those who did take on vegetable production as their main activity (farmers 4, 6, 7, and 8), several outperformed the other farmers.

An important caveat to these data is that, on average, the irrigation systems were used for only 58 % of the time they were installed. The remaining 42 % of the time they were idle due to lack of water access. (Correspondingly, profit over operational months is roughly a factor of two higher than profit over all months since installation.) A majority of BDJ farmers use small, earthen dams called açudes for irrigation. For varying amounts of time, these dams run dry during the annual dry season (from September to January). As such, BDJ farmers participating in this experiment could not irrigate year-round and therefore only reached a fraction of their production capacity. More severe droughts further limited productivity. During the heavy drought of 2012, none of the farmers were able to irrigate because all water sources dried out; farmers could not produce enough revenue from their systems to make loan repayments. These data suggest that irrigation is fundamentally limited as an adaptation strategy by overall water access. This is discussed in greater detail below, and in the SI.

4.2 Balanced animal feed.

Prior to the interventions, none of the dairy or goat farmers had received training on feed calculations for their livestock; consequently, none were feeding their animals an appropriate balance of roughage, carbohydrates (energy), and protein. With consultation for the particular breed of animal, feeding plans were devised. Animal milk production and weight gain were monitored before and after introduction of balanced feed; results are presented in Tables S3 and S4 for milk and meat, respectively.

Table S3 presents the results for the dairy cow experiment. Baseline values of productivity and feed costs (the non-optimized baseline feeding practices) are presented, as well as values at the end of the pilot period. At the end of 1 month, milk productivity increased, on average, by 52 % (Table S3 ). Net income from milk production also rose dramatically (49 % average). Although productivity rose for all cows, one cow saw net income decrease; it was later determined that this cow was nearing the end of her lactation period when the experiment began. (Excluding this cow from the analysis results in an average productivity increase of 57 % and a profit increase of 65 %).

The data for the meat experiment (Table S4 ) are similarly impressive. For reference, pastured goats typically gain 1 kg/month, so the 30- and 45- day weight gains represent changes 4 or 5 times the baseline expectation. At the end of 45 days, one farmer’s goats had gained an average of 2.8 kg of muscle mass (meat), or an increase of 19.5 %; the other farmer’s goats had gained 4.3 kg (26 %) more meat after 30 days. The two farmers earned a net profit per animal of $129 and $148, respectively. These profits are directly proportional to the additional muscle mass gained by the animals (as payment is based on weight of meat when butchered).

These data for the returns to a fairly straightforward diet optimization are encouraging; limitations to this study and policy implications are discussed in detail below.

5 Discussion.

This study aims (i) to outline the impact of climate change on key local food chains of the Bacia do Jacuipe county, Bahia; and (ii) test and evaluate the contribution that efficient irrigation and a balanced animal feed could have in increasing farmers’ resilience in the study area. This is necessary step to start building a database of strategies and technologies shown to work locally and that could incorporated, in a bottom-up fashion, into specific development and climate change adaptation programs.

The drip irrigation study here represents some of the longest data on the use of irrigation in developing communities and is thus immensely valuable. These data suggest that irrigation is only a moderately effective adaptation strategy, since in the worst years, lack of reliable water access precluded use. This study has further underscored that irrigation with ephemeral water sources is inherently risky and may not be economically viable during drier periods. (This corroborates earlier work, e. g. Burney and Naylor 2012 .) To be a successful adaptation strategy, irrigation thus requires additional work to secure water access year-round, through storage, access to groundwater, or construction of larger catchments. The Brazilian government has undertaken several projects to construct water cisterns for smallholders in the Sertão and elsewhere; an obvious departure point for future research would be to test the effectiveness of irrigation in conjunction with cisterns. It would be important to understand whether such cisterns outperform the acude s.

However, if access to a stable water supply is secured such that farmers are able to use systems year-round, the data from this pilot project are very promising. Including the value of garden products consumed at home (as an offset cost), the median net profit to date for all eight farmers is R$1,361. Assuming variable costs remain similar, after payback of the initial capital investment median annual profit is over $3,300. The Net Present Value (NPV) of all of the systems (10 %, 5 years) is positive (median = $8,403), and all systems have an Internal Rate of Return (IRR) over 10 %, a common metric for development projects reflecting the likely cost of capital through private channels. If used year-round, payback time for the systems ranges from just under 1 year to just over 3 years (for the PV system).

The milk and meat trials were very successful. Overall, these results heavily support extension and education on balanced feeding practices, since this simple education pilot to help farmers optimize their cattle feed had profound impacts on productivity and profit. The milk trial was too short and small to include any impacts on landcover, but these data suggest that dairy farmers in the Sertão should be able to intensify production profitably, and at the same time lessen impact on the environment. However, programs built around improved feeding practices will have to come with an understanding to the limits farmers’ land impose on voluminous roughage. That is, technical advisers to dairy farmers should help farmers maximize their own forage production and then size their herd accordingly. Many pastoralists in the area have started producing new forage crops, like palma forageira (prickly pear cactus), which improves the volume of roughage available without contributing to the rampant problem of overgrazing and subsequent habitat loss, deforestation, drying, and soil compactification. Future research should study, in a controlled manner, the impact use of palma has on productivity and landcover. This would be an important contribution to the literature exploring the possibilities of simultaneous economic and environmental sustainability in smallholder production systems.

6 Policy relevance and conclusions.

Northeastern Brazil has long featured a top-down policy-led approach, where the Federal and State governments collaborate to address specific needs. Gutiérrez et al. ( 2014 ) made one of the most detailed and comprehensive description of policies and programs that are currently used to alleviate droughts impacts in semi-arid Brazil. These range from water truck programs to insurance, well drilling, cash transfer (“Bolsa estiagem”) and credit, among others. Although all of these programs have been justified as emergency measures, these actions come without clear discussion about what kinds of technologies should be bought with government funds to decrease the impact of drought. Moreover, the categorization of these interventions as “emergency” actions means they are put in place when conditions are already straining smallholders, and none of these policies are put into a longer climate change perspective. Resilience is not about response to any one particular climate event, but is instead built through time—especially during good rainy years, when the farmer has time and resources to organize his/her farm to face longer droughts.

Climate records show that over the last 50 years, average annual precipitation in BDJ has decreased by more than 300 mm (−30 %) and average daily temperature has increased by approximately 2 °C (twice the global average for the latter). These changes have altered smallholder life, pushing farmers into pastoralism as staple crop production has become less and less profitable. Nevertheless, this shift has not protected smallholders from climate vulnerability. Recent records show extreme sensitivity of livestock to climate in BDJ: rising temperatures, decreasing rainfall and increasing deforestation rates expose livestock to ever-increasing environmental stress, thereby reducing their productivity. Milk production has already decreased significantly in BDJ. Such conditions make it difficult for farmers to grow their own feedstock. Worst of all, forecast climate trends threaten to further undermine the region’s agriculture and livestock industry—the primary source of economic productivity. The severe drought of 2010–2012 highlights the socio-economic vulnerability of the region.

The Adapta Sertão coalition has tried to understand, through applied research at a farm level, how balanced animal feeding practices and the use of water-efficient irrigation systems can break this vicious cycle of low agricultural productivity and environmental degradation. Our pilot results on efficient irrigation and improved animal feeding practices show tremendous promise, and highlight important considerations for policymakers. First, irrigation and feeding practices are both profitable, but fundamentally limited by water availability (total stored capacity for irrigation, and production of forage for livestock). Programs to augment smallholder water access, through catchments or groundwater access, are therefore key for maximizing returns to irrigation investments. It is important that where such programs are introduced, groundwater extraction be regulated based on the recharge rate of the aquifer so as not to deplete groundwater resources, as has happened elsewhere in Bahia. Likewise, extension programs to promote balanced feeding practices must be accompanied by programs that help smallholders grow more forage on less water and a smaller land footprint, and help them rehabilitate degraded lands for better forage productivity. Such programs must be accompanied by institutions and policies that will enable farmers to more easily access supplemental protein and calorie feeds. (For example, farmers in BDJ were able to access these feeds through farmer cooperatives, which may need to be strengthened in other regions.) Both irrigation and balanced feed initiatives could be integrated with comprehensive soil management programs.

The magnitude (and strong statistical significance) of climate trends in BDJ in recent decades underscores the need for policy support in mainstreaming specific strategies and technologies (like the ones outlined in this study). The process outlined here—understanding localized climate impacts and the region-specific dynamics of smallholder vulnerability—should be undertaken across the Sertão, where climate trends and conditions may differ. Policies and programs rooted in these findings can then help simultaneously make farmers more resilient to climate change impacts and sustain the local bioma—the caatinga—at the basis of regional agricultural production.

The federal definition “smallholder” is based on socioeconomic status and rural classification, and varies according to region. In this study area, smallholders are defined as owning less than 70 ha of land. All of the farmers fit this criteria, and live on their farms (they are small family operations). As such, we use the terms smallholder and family farmer interchangeably here.