Climate change has alarmingly affected the agricultural sector with far-reaching social, economic and environmental impacts.

There are numerous effects of climate change on agriculture, many of which are making it harder for farmers to provide food security. Rising temperatures and changing weather patterns often result in lower crop yields due to water scarcity caused by drought, heatwaves and flooding.

These effects can also increase the risk of several regions suffering simultaneous crop failures. If these simultaneous crop failures happen, they will have significant consequences for the global food supply.

Many pests and plant diseases are expected to either become more prevalent or spread to new regions. Livestock could be affected by many of the same issues, including greater heat stress, animal feed shortages, and the spread of parasites and vector-borne diseases.

The increased atmospheric carbon dioxide (CO2) level from human activities (mainly burning fossil fuels) causes a CO2 fertilisation effect, which offsets a small portion of the detrimental effects of climate change on agriculture.

However, it comes at the expense of lower levels of essential micronutrients in the crops. Other effects include erosion, changes in soil fertility, and the length of growing seasons.  

Also, bacteria like Salmonella and fungi that produce mycotoxins grow faster as the climate warms. Their growth has significant effects on food safety, food loss and prices.

The leading journal Science recently published what’s believed to be the most comprehensive scientific review ever undertaken into how climate change is likely to exacerbate the significant environmental impacts that agriculture already makes on our planet.

Environmental impacts  

Led by scientists from China’s Chongqing University alongside numerous international institutions, including The Nature Conservancy, the study catalogues the extent to which the long-term health of people and nature depends on the resilience and sustainability of food production systems in light of ongoing climate change.

“This paper highlights where agriculture’s negative environmental impacts could be further magnified as the climate crisis deepens, exacerbating greenhouse gas emissions, nutrient pollution, and habitat and soil loss,” said lead author Yi Yang of Chongqing University.

The study predicts that climate change is likely to compound agriculture’s existing impacts by shrinking harvests, reducing the effectiveness of synthetic inputs like fertilisers, and accelerating the damage caused by crop pests and soil erosion.

Declining yields and fertility loss could lead in turn to increased clearing of land for food production, causing the loss of wildlife habitat and biodiversity, while also necessitating increased application of fertiliser and pesticides to maintain productivity, with knock-on effects for surrounding ecosystems.

Perhaps most worrying are the feedback loops highlighted by this study that threaten to exacerbate agriculture’s environmental impacts, even as the sector pivots to respond to climate-driven demands – from rice paddies emitting increased levels of the powerful greenhouse gas methane (CH4) and degraded soil releasing higher levels of nitrous oxide (N2O), to land clearance and soil tillage accelerating land-based carbon emissions.

Although climate change is making it harder to achieve sustainable agriculture, there is hope.  

“Fortunately, many of the practices that make agriculture more sustainable and resilient can also help slow climate change,” said David Tilman, Regents professor and McKnight presidential chair in Ecology at the University of Minnesota.

Approaches that promote soil health, such as cover crops, no-till, and crop diversification, can also increase the ability of agricultural soils to store carbon. One approach that has proved effective in tackling climate change is agroforestry, generating multiple livelihood and environmental benefits.

Agroforestry supports ecosystem services, such as regulation of water and sediment flows, and carbon and nutrient cycling in soils – leading to increased soil fertility, reduced soil erosion and flood and pest control.

Smallholder farmers can also benefit from agroforestry through increased farm productivity, diversified produce and reduction of external inputs such as conventional fertilisers and chemicals for pest management, leading to increased income.

Agroforestry can diversify farmer revenue, provide shade for livestock, and serve as windbreaks while also sequestering further carbon. More efficient fertiliser use reduces water pollution as well as emissions of nitrous oxide (N2O) – a greenhouse gas 300 times as powerful as CO2.

Most importantly, agroforestry can help to mitigate climate change and help farmers to adapt to extreme and variable weather. How does agroforestry reduce farmers’ vulnerability to climate change? New research shows at least five ways.

Kristi Foster, quoting a new study by Tannis Thorlakson from Harvard’s Sustainability Science Program and Henry Neufeldt, head of climate research at the World Agroforestry Centre (ICRAF), explored just how agroforestry can help reduce farmers’ vulnerability, using a farmer-managed agroforestry project developed by ICRAF and located in Nyando, Kisumu County.

Improving lives

According to climate models, warmer temperatures, greater rainfall variability, and increasingly severe and frequent extreme weather events are in store.

These changes are expected to decrease agricultural productivity in the developing world, carrying a host of negative repercussions for farmers.

Among those most vulnerable are people farming at the subsistence level, partly because they lack the money to invest in innovative practices.  

The Nyando study, whose results are published in the journal Agriculture & Food Security, compared two types of farmers – those who had been involved in agroforestry development for 2 to 4 years, and neighbouring farmers without agroforestry training.

The agroforestry project was still in its infancy, yet the research showed that farmers’ general standard of living benefited from agroforestry practices in a number of ways.

First, 43 per cent of farmers who planted trees on their land noted improved farm productivity through decreased soil erosion and increased soil fertility.

Second, 70 per cent of farmers who took up agroforestry practices benefited from environmental sustainability, primarily soil erosion control.

Third, households involved in an agroforestry project for four years averaged Ksh24,000 more in household wealth than their neighbours.

Fourth 87.5 per cent of farmers who had planted trees four years earlier experienced an increase in earnings through income diversification, and fifth, trees provided farmers with several specific coping strategies in the face of drought and floods.  

The research was conducted at a time when the area had recently suffered from a drought, a flood and variability in precipitation, resulting in widespread food shortages.

Farmers are currently unable to cope with these climate-related stresses in a sustainable way, with several coping strategies leading farmers deeper into the poverty trap.

To cope with more variable and intense climate stresses in future, farmers feel that improving their general standard of living is the most effective way to adapt.

Food security is their main concern, and they expressed interest in increasing farm productivity, diversifying income and improving environmental sustainability.

To maximise the effectiveness of future agroforestry projects, agriculture and agroforestry training should be linked to combine the short-term benefits of agricultural knowledge and the long-term benefits of agroforestry practices.

With future climate unpredictability, the capacity of agroforestry to improve farmers’ well-being across a range of climate scenarios holds particular promise.  

Viewed as a valuable component of a broader development strategy, agroforestry has considerable potential to help farmers adapt to the myriad climate shocks and stresses that lie in store.