How we feed the 9 million people on our warming planet

What we grow where is changing dramatically as global warming causes more and more disruption to food production

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Report by Mark Rowe

The era of global boiling has arrived,’ declared the UN secretary general, António Guterres, as scientists confirmed that last July was the hottest month on record. Charon, the anticyclone that sat over southern Europe, along with temperature spikes in the USA and Canada, and, last year, in the UK, have brought into sharp focus what is arguably the gravest implication of climate change for humans: food production. 

Heat accounts for 28 per cent of the impacts of climate change on agriculture, says the UN Food and Agriculture Organisation (FAO), while Hunger in a Heating World, a 2022 report by Oxfam, described ‘the correlation between weather-related crises and rising hunger … [as] stark and undeniable.’ According to the report, without technological advancements or measures to stop warming in its tracks, by the end of this century, South Asia will see a 30 per cent reduction in its wheat and maize (corn) crop yields. Long before then, by 2030, 38 million additional people in Asia and the Pacific ‘are likely to be pushed into hunger’.

Here and now

Heat impacts on food production now regularly manifest themselves. The latest IPCC report, published in March 2023, concluded that climate change is now affecting food security through increasing temperatures. 

This spring, the Spanish farming association reported that drought had ‘asphyxiated’ 60 per cent of the countryside in Spain and created ‘irreversible losses’ of more than 3.5 million hectares of rain-fed cereals. Some farmers chose not to plant crops for fear of losses. Cereal production across southern Europe was expected to fall by 60 per cent compared to last year, according to Copa Cogeca, the European farming organisation, while cucumbers, lettuces and peppers were also affected.

We are, according to Jonas Jägermeyr, a crop modeller and climate scientist at NASA’s Goddard Institute for Space Studies and the Climate School at Columbia University, in ‘the time of emergence’ – the point at which local realities change beyond the norms.

‘We have been worried about this for years, saying the issue was going to get worse – now it is,’ says Zitouni Ould-Dada, deputy director of the FAO Office of Climate Change, Biodiversity and Environment. ‘Crops need a norm; any changes or disruption to cycles will lead to negative impacts. Some crops simply won’t grow in certain areas any more. Drought affects the quality of the soil, the minerals, the productivity of the plant.’ 

One of the first indicators of what was to come was the European heatwave of 2003, according to Pedram Rowhani, reader in geography at the School of Global Studies at the University of Sussex. ‘Crop production in France, Italy, central Europe massively declined because they simply could not grow.’

According to Jägermeyr, in heatwaves of between 32°C and 35°C, the issue for crops is water stress.   Temperatures above that start to damage a plant’s tissue. During the European heatwave this summer, olive trees simply dropped their flowers in the heat and conserved their water instead, leading to lower olive oil production and higher costs. 

Winners and losers

The impacts are complex. Research by both NASA and the IPCC shows that yields of some crops, such as maize and wheat in many lower-latitude regions, have already been affected by climate change. At the same time, yields of maize, wheat and sugar beet have been affected positively in higher latitudes in recent decades. A 2021 NASA study, published in Nature Food, concluded that maize crop yields were projected to decline 24 per cent, while wheat could potentially see growth of 17 per cent, with regions to benefit including the northern USA and Canada, the North China plains, Central Asia, southern Australia and East Africa. Soybean projections showed a decline in some regions, but the modelling here was less conclusive.

Boiling Point, a report by the International Monetary Fund, found that by 2100, rice yields in Indonesia, the Philippines, Thailand and Vietnam could drop by as much as 50 per cent from 1990 levels. ‘A 20 per cent decrease from current production levels could have severe implications worldwide,’ says Jägermeyr. As ever, wealthy, developed nations are better placed to access, silience to impacts, and mitigate – to some extent – the harm done by heat extremes. 

Although some crops may thrive in higher latitudes, this can’t be an excuse for inaction on climate change, warns Ould-Dada. ‘Some crops are more tolerant of heat but, over time, if these temperatures become the norm, and are followed by occasional higher extremes, all crops eventually get affected.’

In addition, several factors determine where crops will grow. ‘North America, Siberia, northern Europe, northern China look to potentially benefit,’ says Jägermeyr, ‘but crops grow where they currently do for a reason. It’s not just heat but soil quality and whether they are close to market.’

Baking bread

The world’s key breadbaskets, found in a dozen nations, including the US Midwest, Ukraine, Pakistan, Australia, Argentina and Brazil, face more disruption from increased heat than they do from increased rainfall, according to Rowhani. ‘Crops have a threshold of heat,’ he says. ‘When things go beyond that threshold, they start to suffer substantially.’ 

The main danger occurs when extreme heat coincides with growing processes such as flowering. Then, says Rowhani, ‘photosynthesis cannot happen; the plant can’t produce its fruit – the bit we eat.’ 

Rowhani also cautions against seeking comfort from medium-term gains in the Global North. ‘In 20–30 years, we will see wheat growing apparently quite well in higher latitudes, but most of the damage happening now and in the next 10–20 years will happen in the tropics, where it is already getting tougher and tougher to grow crops.’

Decades of progress at risk?

The past 60 years of global development have been underpinned by a transformation in global food systems, known as the Green Revolution. Since 1961, says the IPCC, the supply of global per capita food calories has increased by 33 per cent, with the consumption of vegetable oils and meat more than doubling. Croplands now cover 12–14 per cent of the global ice-free surface. The current food system (comprising production, transport, processing, packaging, storage, retail and consumption) feeds the great majority of the world’s population and supports the livelihoods of one billion people (this is, of course, far from perfect – the FAO estimates some 151 million children under five are stunted and 821 million people are currently undernourished, while two billion adults are overweight or obese). ‘By 2050, we will have ten billion people to feed and nourish in a world where many crops will no longer be grown in the way they are now, where they are now,’ says Ould-Dada.

Rising costs 

Smaller yields and changing growing zones could lead to greater use of fertilisers and water, and the further loss of biodiversity. All this could jeopardise our capacity to achieve many of the UN Sustainable Development Goals. The 2023 IPCC report described impacts on agricultural and crop production, and fisheries yields and aquaculture production as ‘adverse, widespread, observed and substantial’.

The IPCC projects a profoundly uncertain future as competition for available land intensifies. Cereal prices could rise by just one per cent by 2050; or they could soar by 29 per cent. At such a point, the knock-on effects of the interconnected nature of the global food system could become profound, the IPCC warns. 

Rice is a staple for some 3.5 billion people across the planet, providing 20 per cent of calories consumed worldwide by humans, mainly across Asia, some African regions and Latin America. Rice won’t disappear as the world heats, but its optimum climate may well shift north, with huge social and financial repercussions where it’s integral to the economics and social fabric, particularly the ten main rice producers, all of which, apart from Brazil, are in Asia.

‘The whole situation is worrying; it’s keeping people up at night,’ says Ould-Dada. ‘It’s confusing for farmers – planting times are getting muddled, there’s either not enough water or too much.’ At greatest risk are smallholder farmers, who produce the majority of food, particularly in small island states and in Africa. They’re having to adapt their schedules, to transition to more heat-tolerant plants or manage water stress.’  

Another issue is practical: heat stress on farmers. Under a 4°C warming scenario, there’s a 30 per cent chance of a whole month of days in parts of Asia in any given year when it’s too hot to work outside, meaning less time to harvest or plant crops. ‘When it’s 50°C, you can’t go out, but also, your crops will just burn up,’ says Rowhani.

Livestock feel the heat

Livestock are just as vulnerable to heat stress, with knock-on impacts for cattle reared for meat and dairy animals. ‘When it gets really hot, the livestock’s metabolism is impacted,’ says Rowhani. ‘If the grass is no longer there, what happens? Herds will be devastated.’

Pastoral systems of food production, found in three-quarters of the world’s nations and practised by up to 500 million people, are especially vulnerable, according to the IPCC. ‘For pastoralists, livestock is their livelihood,’ says Rowhani, who is working on a project with pastoralists in eastern Africa that provides an early-warning system to provide alerts of extreme heat. ‘This can allow them to de-stock, try to buy fodder or disperse, if possible, to cooler areas.’

Rowhani suggests the need for a rethink, to re-direct maize and soy – currently used to feed animals – to human consumption. ‘If we want to retain meat as a source of protein, then current moves to provide insects for human consumption could be scaled up to feed livestock too,’ he says.

Many pastoralists have begun switching from herding to growing vegetables, but as the IPCC points out, they’re now encountering another problem. Heat speeds up the development of annual vegetables, resulting in yield loss and impaired product quality. According to the IPCC’s Special Report on Climate Change and Land, increased CO2 is projected to be beneficial for crop productivity at lower temperature increases but this is highly likely to come with lower nutritional quality. ‘If you rush through your growth stages, by the end of the season, you just haven’t collected as much energy,’ says Jägermeyr. 

In theory, he adds, this might be offset by longer growing seasons that enable more plantings to be cultivated and could lead to higher annual yields – although many fruit and vegetables require a cold spell to produce viable harvests, something that may become less common with milder winters.

Warming waters

Meanwhile, fisheries and aquaculture face issues around warmer waters and acidification. ‘Fishing communities rely on norms but fish and prawns are very sensitive to temperature variations, so when you hit 50°C, that will have a huge impact of fish farms,’ says Ould-Dada. ‘The impacts can be even greater [than on land]. Fish will simply move to higher latitudes and in many cases, the fishers will not be able to follow them. It’s hard if you depend on that species for your income.’

West African fishers will turn to previously overlooked species or those that move into the newly opened up ecological niche. ‘They won’t be fussy – but the same applies to counties such as the UK, where our obsession with cod is going to have to shift if we want to continue to eat fish,’ says Ould-Dada. 

Diversify, be creative or wither

A heating world, says Ould-Dada, ‘is obliging us to re-think how we produce food, process it and store it’; the challenge, as Jägermeyr points out, is that ‘we can’t stop eating overnight’. The key message, argues the former, is for farmers to exchange best practice and diversify: should one crop fall to heat, another may grow. Farmers could be creative, for example, by installing solar panels in fields; plants benefit from shade and the panels generate electricity and gather rainwater. Food production’s contribution to climate change – 21–37 per cent of greenhouse gas emissions are attributed to our food system – also needs to be factored in. ‘We have to do this in a way that benefits nature, the livelihoods of farmers and local communities,’ adds Ould-Dada. ‘We have to move away from subsidising the growing of food to subsidising the protection of the soil.’ 

Incorporating trees and shrubbery into crop and livestock farming systems, suggested a 2023 report by the Energy & Climate Intelligence Unit, can provide shade, improve soils, sequester carbon and foster biodiversity. Other measures for managing longer-term soil health include organic fertilisers, diversity in crop rotations and reducing soil disturbance. Technology transfers, such as precision farming, should assist poorer nations, says Rowhani, so that in extreme heat, water is targeted at individual areas of fields that need it most.

Any adaptations also require a reset in how we grow food.  ‘At the global level, food security is threatened; the Green Revolution is probably going to stall,’ says Rowhani. ‘But the Green Revolution came at a huge environmental cost. We can’t continue to destroy the environment to grow our food.’

Food supply is dominated by four or five commodities, so the potential for diversification – to turn to crops that use less water and are more heat tolerant – is huge. In India, a political drive is encouraging farmers to switch from rice to millet. In Egypt, a similar emphasis is placed on growing chickpeas rather than wheat. In West Africa, schemes are exploring the greater growing of fonio, a species of millet with small grains (Guinea accounts for 75 per cent of all world production);  fast-growing, fonio is known as ‘hungry rice’ as it’s harvested before other grains.

Waste not, want not

Some good news. At least one answer is entirely in our own hands: we can simply eat less and discard less food. Ould-Dada points out we have 800 million people who go to bed hungry every night while simultaneously two billion humans are clinically obese or overweight. ‘We throw away a third of all food produced,’ he says. ‘If we reduce that, it makes the challenges easier. It’s as big an issue as wasting electricity. Everyone understands about turning off your lights – why don’t we think the same about food waste?’

We have the answers, do we have the will?

‘Maybe it’s human nature,’ says Ould-Dada, ‘we leave things to the last minute but we do have the answers, the technology – but we just need the disposition. We have to be optimistic; it’s our lives that are being affected. The problem is that we still don’t take it seriously; people aren’t scared enough. 

‘We have one hot summer, a bad harvest and everyone assumes the next year will be back to normal, but it won’t. We’ve got a new climate reality, a new agricultural reality and it’s happened sooner than anyone predicted. We can’t continue as before and expect business as usual.’

Having worked on food security for 15 years, Rowhani is uncertain how things will work out. ‘It’s not an easy task as this will require political will and system change. This is not something any country can do on its own, we need global answers.’

Although it won’t be easy, ‘we can pull it off’, says Jägermeyr. ‘Humanity is not going to die out. The problem is whether we are going to change fast enough to avoid large, harmful costs. The longer we wait, the more complacent we are, the more humanity will pay for it, especially in the Global South.’