'Climate Smart' agriculture
Climate-smart agriculture (CSA) aims to address the interlinked challenges of climate change and food security, which measures food availability and people’s access to it. CSA has three goals: to reduce the GHG emissions from agriculture, to increase agricultural productivity and to enhance resilience in agricultural systems.
Reducing GHG emissions and increasing productivity
Agriculture produces 29% of greenhouse gas emissions, putting it on a par with the transport sector. But here is the good news: reducing greenhouse gases in agriculture is generally cost-effective and, unlike all other economic sectors, will not reduce productivity. In fact, some measures actually increase productivity, by creating more efficient farming systems. Here are the priority actions:
• Reduce meat and dairy production
• Increase efficiency in meat and dairy production
• Improve manure management (eg better storage and methane capture)
• Reduce reliance on synthetic fertilisers and use these efficiently
• Prevent any further land conversion to agriculture
• Increase soil carbon retention through improved land management
Recent studies have shown that ‘post-farm’ transport and processing are only responsible for a tiny fraction of the greenhouse gas emissions associated with food systems. Therefore local food systems, whilst often valuable for social or economic reasons, will not contribute significantly to climate change mitigation.
Some mitigation measures in industrial and transport sectors could also benefit agriculture. Reducing low-level ozone, for example, increases crop yields and benefits livestock health. Low-level ozone is a greenhouse gas generated in the air from a mix of fuel combustion and sunlight, and is toxic to animals and plants. Low-level ozone pollution causes annual crop losses of 4.5 billion USD in Europe and 4 billion USD in the USA.
However, the shift towards biofuels is not good news for agriculture. Biofuel plantations aim to reduce fossil fuel emissions but compete with land for food. The diversion of food for fuel, for example maize to produce ethanol, has been blamed for rising food prices in recent years.
Enhancing resilience in agricultural systems
Production systems need to adapt to climate stresses such as drought, pests, disease and erratic weather patterns. Some crop losses can be prevented by choosing stress-tolerant crop varieties, but in the long-term the focus will be on switching to different crops. In Mexico, for example, there is a move to replace coffee with cocoa because the latter is more tolerant of climate change-related blight and heat stress. Cassava is heralded as the climate change crop for many parts of Africa, and could replace major food staples such as beans and potato.
Increasing biological diversity in agricultural systems enhances resilience. Growing a wider range of crop varieties or crops is like an insurance policy. It helps to guarantee a harvest, whatever the combination of stresses in any particular growing season. The provision of habitats for biodiversity helps to generate ecosystem services, for example by protecting the soil from wind erosion, or providing places for pollinators to live. You will find out more in Week 4 (step 4.8).
Agroforestry, where trees are grown in grazing pastures or croplands, may also contribute to climate resilience. In Niger, for example, farmers have increased maize yields by allowing the natural regrowth of native Faidherbia trees in crop fields. The trees fix nitrogen in the soil, protect fields from wind, soil erosion and water loss and add to soil organic matter through leaf fall.
Water is a critical resource in agriculture and there is huge scope for improving water management, especially in irrigation, where only 65% of the water used globally actually reaches the crop. Improvements include smarter monitoring of crop water requirements, the use of drip irrigation systems (which deliver water directly to the crop roots), rainwater harvesting systems and the re-use of waste water.
Better management of soil, nutrients and soil erosion is also a priority. Practices include reduced tillage of soil and cover crops, and you will find out more in the next few steps. Good soil management increases soil carbon: not only is this good news for soil carbon capture but it also creates healthier soils that can hold more water.
For the next activity we ask you to reflect on how extreme weather has affected food production in the location of your choice. Has there been an extreme weather event near you recently?
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