Extreme heat this summer has already killed 1,300 Muslims on the annual hajj to Mecca, but climate change will threaten the lives of far more people if crops start failing due to rising heat and water stress, recent research has shown.

Scientists used a unique large-dimensional computational global climate and trade model, GTAP-DynW, to directly project the possible intertemporal impacts of water and heat stress on global food supply and food security to 2050, climatologists Tom Kompas, Tuong Nhu Che and R. Quentin Grafton from the Centre of Excellence for Biosecurity Risk Analysis and the Centre for Environmental and Economic Research, at the University of Melbourne, said in a recent paper in Scientific Reports.

The study used three models that came up with unsettling predictions of substantial declines in global food production of some 6%, 10% and 14% to 2050 that will put an additional 556mn, 935mn and 1.36bn into severe food insecurity by 2050 compared to the 2020 model baseline.

“Climate change is a serious threat to food production systems that are highly dependent on water resources and ecosystems, at multiple scales,” the scientists said. “Various regions already suffer from water cycle disruptions due to climate change which include intensification of extreme weather events (e.g., droughts, floods) and groundwater depletion. Critical future risks include heat stress and water stress on global food production and, thus, food security. Climate change risks are magnified by increasing water withdrawals for households and industry to 2050, especially for irrigated agriculture that accounts for about 70% of total water withdrawals and supplies up to 40% of the global human-consumed calories.”

Like most studies on how the Climate Crisis will unfold, this one’s conclusion remains uncertain, as so many factors are at play. To quantitatively assess these risks for global food production and food security requires a Computable General Equilibrium (CGE) model, connected to a climate change model, to capture price, trade and income effects in relation to both food supply and demand.

However, as bne IntelliNews reported, it is already clear that global rainfall patterns will change dramatically, with new droughts and deluges becoming more extreme. And as it is increasingly believed that the climate models are wrong, the Climate Crisis is already accelerating as all-time record temperatures highs have been registering on a weekly basis over the last year and a half.

All the scenarios are bad

Despite all the variables, all of the models developed by the Melbourne team predict substantial falls in food supplies out to 2050 that could affect as much as a tenth of the world’s population by 2050.

The worst-case scenario (SSP2-RCP8.5) sees food production drop by 9.7% from 9.75mn giga-calories (Gcal) to 9.2mn, which will threaten the food security of almost a billion (935mn) additional people.

Decreasing trend of food production as a percentage reduction in 2050 from 2020 for worst-case SSP2-RCP8.5 climate change scenario

The distribution of the impact of the Climate Crisis on food varies by region. For the mildest scenario (SSP2-RCP4.5) that sees global food production shrinking by 5.8%, putting an additional 556mn into food insecurity, food production from both water and heat stress is projected to decline by 5.1-6.6% in Africa, 5.8% in Australia, and 6.4% for some parts of South America.

The US gets off relatively lightly by 2050, with food production projected to drop by a relatively modest 4.8%; however, the two most populous countries in the world will see some of the biggest falls in food production: 9.0% for China and 6.5% for India.

In the worst-case scenario (SSP3-RCP8.5), food production is projected to decline by 8.2-11.8% in Africa, 14.7% for Australia and 19.4% for some parts of Central America. In this scenario the US suffers much more, with food production predicted to fall by a whopping 12.6%, while China and India see catastrophic falls in food production of 22.4% and 16.1% respectively.

Food insecurity needs to be trade adjusted, as some countries like Russia produce a surplus of grain and exports, whereas other countries remain dependent on imports to meet their nutritional needs. A fall in their domestically produced food production does not necessarily increase their domestic food insecurity (e.g., Australia, France, Russia and the USA).

“Overall, Africa is the most threatened in terms of severe food insecurity because of reductions in the continent’s food production due to water and heat stress and because of the projected increase in Africa’s population by 2050. Other regions with substantial increases in severe food insecurity include the Middle East, South Asia and Central America,” the scientists said.

Countries with severe food insecurity by region in 2050 relative to 2020 (% population range)

In the worst-case scenario domestic food production in many African countries will provide less than half of their domestic food demand. Some regions, such as China and ASEAN countries, switch from being net food exporters to food importers by 2050, with a need to import from food-producing regions that have been affected by climate change.

And the cost of food will grow. The world has already had a foretaste of climate-driven food price inflation during the recent global pandemic when global food supply chains were disrupted, although overall production of food remains stable. Things will get much worse when agricultural yields begin to fall as a result of deteriorating weather conditions.

“In all cases, model results show that there are substantial increases in food prices overall, and especially for the most extreme scenario and for those regions with high water stress,” the scientists predict. “Our results show an increased flow of trade in agricultural commodities from low to high water stress countries and regions, given (in part) by the relative regional food price changes. Food exports to China, from lower water stress countries, increase across all three scenarios.”

Food crisis is already here

There is little doubt that the rapidly accelerating Climate Crisis will have a sizable impact on agriculture as the milder changes to date have already had an impact on global food production.

“Climate change has already had a substantial and negative impact on global agricultural productivity, reducing a global measure of agricultural productivity by about 20% since 1970, with larger negative impacts in the Near East and North Africa,” t4he scientists say. “To what extent technological change can offset yield declines from climate change is uncertain. Future water availability for increased food production is also uncertain as the irrigated area in water-stressed regions is increasing, including in major food-producing regions such as China, India, Pakistan and the United States. In part, this is because the area in irrigation drives irrigated water withdrawals in these countries and because climate change will likely increase crop demand by further expanding irrigation.”

Water supplies are also already declining. As bne IntelliNews reported, last summer most of Central Asia introduced water rationing as it faced a double whammy of a rapidly growing population and falling water supplies causing droughts. The global changes in rainfall patterns are only likely to exacerbate these problems.

This year India has been particularly hard hit by a series of heat waves across a band in the north of the country that has seen birds and monkeys drop dead out of the trees in New Delhi and has led to water riots in regional cities as the water infrastructure breaks down. The bread baskets of India have faced temperatures over 44°C for nearly 40 days straight. Agriculture cannot survive in these extreme temperatures and droughts for long.

“There are 900mn people living and growing food in this area alone,” Lee Simons, a climatologist, said in a post on social media. “Warming rapidly accelerates and monsoon rains change as air pollution decreases and greenhouse gas emissions continue. How bad does it need to get before this receives the attention it deserves?”

Global studies of the decline in terrestrial water storage show statistically significant declines in global storages over the period 1992-2020 in about half of all 1,058 natural lakes and 922 global reservoirs, the scientists report.

“Over half of the decline in the storages is attributable to water withdrawals, increasing temperatures and potential evapotranspiration,” the scientists say.

The OECD highlights that water stress, in the absence of effective policy actions in terms of water management, will significantly and negatively affect agricultural production in Northeast China, Northwest India and Southwest United States.

“These locations are in the world’s three largest food producing countries, all of which are currently net food exporters and have the biggest cumulative food footprints,” the scientists say. “Other modelling in the existing literature highlights that the frequency of crop yield failures with climate change could be many times greater for key cereal crops (rice, soybean, maize and wheat) that account for about two-thirds of food calorie consumption for China, India and the USA over the period 2041-2060,” the paper warns.

Again, the world has had a foretaste of these problems last year, when a rice crisis struck India after yields plummeted, forcing the government to ban all exports of non-basmati white rice to ensure sufficient supplies at home and moderate prices that the poorest segments of society could afford. India is the world’s biggest producer and exporter of rice and the export ban caused chaos throughout Southeast Asia, sending prices soaring in neighbouring countries that only exacerbated food insecurity as the cost of food exceeds the ability of the poorest to pay for it.