Summary of climate resilient crops

• As climate change worsens, food manufacturers must find crops which are resilient to heat and drought pressures
• Some crops are more resilient than others
• Crops such as millet, amaranth and sweet potato are drought and heat resistant and can grow in harsher conditions
• They are also nutrient-dense, meaning they can provide a replacement for less resilient crops
• However, coffee, cocoa and rice are all seeing yields reduced by heat, drought and other climate pressures

Agriculture is at a crossroads. All over the world, weather patterns are affecting yields of key crops, pushing up prices and impacting food security. We are, in other words, in the middle of a commodity crisis.

The meaning of this is yet to become fully clear, and the resilience of agriculture as a whole hangs in the balance.

While no crop is entirely safe from the pressures of climate change, some are more resilient than others.

Resilient: Millet

Millet is a group of small-seeded grasses, mainly grown in the dry areas of Africa and Asia. Many millets are rich in vitamins and minerals like calcium and iron, and also have a high protein and fibre content. Millets are versatile in cooking and are even gluten-free.

Many forms of millet, including sorghum and fonio, are resilient to climate change, so much so that the crop has been recommended by the UN as a climate resilient crop.

Unlike crops such as wheat, rice and corn, millets can grow in drought conditions, and with low levels of rainfall or irrigation. Millet, particularly pearl millet, also has a high tolerance to heat stress and can survive in temperatures of up to 42°C.

Also read → Global commodity supplies at risk as extreme weather escalates

Some types of millet, such as sorghum, are resistant to high salt content in water, which can be useful as freshwater availability declines.

The crop’s high carbon content can also increase carbon levels in the soil, which is according to the UN highly important for sustainable cropping systems.

Less resilient: Coffee

Coffee is one of the world’s most popular beverages. But the crop is highly vulnerable to climate change.

There are two main varieties of coffee: robusta and arabica. Arabica, often considered the higher quality coffee, is the type used for upmarket roasters and “posh” coffee. However, arabica must grow at high altitudes, and rising temperatures are driving it further and further into the mountains.

According to one study, yields of the strain are expected to decline by 23-25% in Latin America and 16–21 % in Africa. Declines will be greater where air temperature is higher.

Robusta, on the other hand, as the name suggests, is more robust. Often used for ‘lower quality’ coffee such as instant, robusta is more resilient to different conditions. Nevertheless, it is not immune to the impacts of climate.

The coffee’s optimum production range was found a few years ago to be lower than previously thought, meaning that it could be more vulnerable to climate pressures.

Resilient: Amaranth

Amaranth is a gluten-free pseudo-grain, rich in protein. It has a malty and nutty taste, comes in seed, flour and flake form, and can be found in processed products such as cereal and pasta. It has been used for centuries and was revered by the Aztecs and Incas.

It is also a climate-resilient crop, withstanding drought and heat pressures where other crops do not fare as well. The grain is highly water use efficient, and can respond to low carbon availability.

One study exposed amaranth to heat shock, finding that it was remarkably tolerant. However, even this plant has limits and when exposed to severe heat stress for a long period of time (50°C or above for four or more hours a day) yields were affected.

Another study found that even when irrigation was altered, the effect on amaranth was minimal, with yields mostly unaffected, suggesting it has high drought tolerance.

The main growing regions for the crop are Africa, South America, and central and southeast Asia.

Less resilient: Rice

Rice is one of the most important crops in the world, contributing around 21% of the world’s caloric intake. Unfortunately, it is also vulnerable to climate pressures, with heatwaves reducing yields in many countries.

Climate stressors have forced rice to move northward in growing regions such as China, changing its suitable cultivation areas. As well as yields dropping, the growth period is expected to shorten.

Alongside high temperatures, rice growth can be impacted by both drought and excessive rainfall.

Even a short span of drought stress during the reproductive phase can negatively impact the size of the crop and reduce yields. Drought can also reduce the ability of photosynthesis and even lead to 100% yield loss in extreme circumstances.

Excessive rainfall can also limit the growth of rice plants, affect grain quality, and make rice more susceptible to crop pests.

Resilient: Sweet potato

Sweet potatoes may not be as versatile as the other crops listed here, but they do provide certain nutritional benefits. They’re rich in fibre, and lower in starch than ordinary potatoes.

The crop has a strong resistance to drought after being rooted, although it is vulnerable to drought during its establishment period. Because of its resilience, it has a higher yield potential than many other crops.

Sweet potatoes are tolerant to high-temperature soils with low fertility, and are also not severely impacted by crop pests.

It can also be cultivated more sustainably, as less chemical fertiliser is required to make it grow.

Less resilient: Cocoa

Cocoa yields have been hit hard by climate change over the past two years, with irregular weather patterns, heat and drought pushing down yields and pushing up prices.

Higher temperatures can reduce cocoa yields by affecting transpiration and photosynthesis. Drought also has an impact on cocoa yields, reducing soil moisture and stressing cocoa trees.

Furthermore, cocoa is vulnerable to crop diseases such as swollen shoot virus in west Africa and witches’ broom in South America.

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