Widespread changes in rainfall and temperature patterns threaten agricultural production and increase the vulnerability of people dependent on agriculture for their livelihoods, which includes most of the world’s poor.
Climate change disrupts food markets, posing population-wide risks to food supply.
Threats can be reduced by increasing the adaptive capacity of farmers as well as increasing resilience and resource use efficiency in agricultural production systems.
CSA promotes coordinated actions by farmers, researchers, private sector, civil society and policymakers towards climate-resilient pathways through four main action areas; building evidence;increasing local institutional effectiveness; fostering coherence between climate and agricultural policies; and linking climate and agricultural financing.
CSA differs from ‘business-as-usual’ approaches by emphasizing the capacity to implement flexible, context-specific solutions, supported by innovative policy and financing actions.
By 2050, an additional 2.4 billion people are expected to be living in developing countries, concentrated in South Asia and sub-Saharan Africa.
In these regions, agriculture is a key eco¬nomic sector and major employment source, but currently more than 20% of the population is on average food-insecure.
About 75% of the world’s poor live in rural areas, and agriculture is their most important income source.
Raising agricultural productivity and incomes in the smallholder production sector is crucial for reducing poverty and achieving food security, as a key element and driver of economic transformation and growth, and within the broader context of urbanization and development of the non-farm sector.
Projections indicate that globally, agricultural production will need to expand by 60% by 2050 to meet increased demand, and most of this will need to come from increased productivity.
Climate change is already hampering agricultural growth. According to the Intergovernmental Panel on Climate Change (IPCC), climate change affects crop production in several regions of the world, with negative effects more common than positive, and developing countries highly vulnerable to further negative impacts.
Increases in the frequency and intensity of extreme events such as drought, heavy rainfall, flooding and high maximum temperatures are already occurring and expected to accelerate in many regions.
Average and seasonal maximum temperatures are projected to continue rising, with higher average rainfall overall.
These effects will not, however, be evenly distributed. Water scar¬city and drought in already dry regions are also likely to increase by the end of the century.
Climate change is estimated to have already reduced global yields of maize and wheat by 3.8% and 5.5% respectively, and sev¬eral researchers warn of steep decreases in crop productivity when temperatures exceed critical physiological thresholds.
Increased climate variability exacerbates production risks and challenges farmers’ coping ability.
Climate change poses a threat to food access for both rural and urban populations by reducing agricultural pro¬duction and incomes, increasing risks and disrupting markets.
Poor producers, the landless and marginalized ethnic groups are particu¬larly vulnerable. The impact of extreme climate events can be long-lasting, as risk exposure and increased uncertainty affect investment incentives and reduce the likelihood of effective farm innovations, while increasing that of low-risk, low-return activities.
Agriculture is also a principal contributor to planetary warming. Total non-carbon-dioxide (CO2) greenhouse gas (GHG) emissions from agriculture in 2010 are estimated at 5.2–5.8 gigatonnes of CO2 equivalent per year (ref. 13), making up about 10–12% of global anthropogenic emissions.
The highest-emitting agricultural categories are enteric fermentation, manure deposited on pasture, synthetic fertilizer, paddy rice cultivation and biomass burning.
The growth of emissions from land-use change is declining, although these still make up about 12% of the total. Given the need for agricultural growth for food secu¬rity, agricultural emissions are projected to increase.
The main sources of projected emission growth, based on assumptions of conventional agricultural growth paths, can also have severe con-sequences for biodiversity and ecosystem services such as water quality and soil protection.
Essential elements of the CSA approach
Unless we change our approach to planning and investment for agricultural growth and development, we risk misallocating human and financial resources, generating agricultural systems incapable of supporting food security and contributing to increasing climate change.
Climate-smart agriculture (CSA) can avoid this ‘lose–lose’ outcome by integrating climate change into the planning and imple¬mentation of sustainable agricultural strategies.
CSA identifies synergies and trade-offs among food security, adaptation and miti¬gation as a basis for informing and reorienting policy in response to climate change. In the absence of such efforts, IPCC projections indicate that agriculture and food systems will be less resilient and food security will be at higher risk.
CSA calls for a set of actions by decision-makers from farm to global level, to enhance the resil¬ience of agricultural systems and livelihoods and reduce the risk of food insecurity in the present as well as the future.
The concept can be illustrated using an IPCC diagram of climate-resilient trans¬formation pathways, adapted to the specific case of agriculture15 (Fig. 1).
Agriculture faces a set of biophysical and socioeconomic stressors, including climate change. Actions taken at various deci¬sion points in the opportunity space determine which pathway is followed: CSA pathways result in higher resilience and lower risks to food security, whereas business as usual leads to higher risks of food security and lower resilience of food and agricultural systems.