More frequent and severe global heatwaves will disrupt future supply chains around the world, a new study has found.
This is expected to trigger a domino effect of losses in major economies including China, which could see GDP loss of up to 5% in just over 25 years, according to the international team of scientists behind the study.
Even temperate countries rarely affected directly by heat stress will not be spared, the study suggests. These are likely to face the knock-on effects as extreme heat hits production in supplier nations, posing risks to food security, energy and mineral products supply worldwide.
The frequency and intensity of heatwaves is forecast to increase as global temperatures rise under climate change. Exposure to extremely high temperatures can cause heat exhaustion and heatstroke, leading even to permanent disability or death.
"By 2060, expected global economic losses will range from 0.6 to 4.6%," the team of climate scientists and economists said in their findings published in the peer-reviewed journal Nature on Thursday.
Developing countries suffer disproportionately from global warming, according to the researchers from universities in Britain, Canada, China and the United States.
The impact includes higher health loss in South-Central Africa, of between two and four times above the global average, and up to 3.3 times more in terms of labour productivity loss in West Africa and Southeast Asia.
"The supply-chain disruption effects are [likely to be] much more widespread, with manufacturing-heavy countries such as China and the US strongly hit," the article said. It forecast economic losses of around 2.7% and 1.8%, respectively, for the world's top two economies.
The study of the likely socioeconomic impact of heat stress by mid-century took into account climate, epidemiological and global trade models.
"We consider health costs related to heat exposure, the value of heat-induced labour productivity loss and indirect losses due to economic disruptions cascading through supply chains," the article said.
Lead author Guan Dabo, a professor of climate change economics at Tsinghua University, said the ripple effect of heatwaves on workers and crops would spread through global supply chains.
"In China, under the scenario of warming of 4 to 7 degrees Celsius (about 39 to 45° Fahrenheit), heatwaves will cause 3 to 5% GDP loss by 2050," he said.
"The loss will partly be caused by a labour productivity drop in China, but more importantly in smaller economies."
These will include close trade partners of China, such as in Africa, which are ill-equipped to adapt to climate change.
"Sectors like construction, mining and agriculture are vulnerable to heatwaves, with few countermeasures available. When raw material imports for these sectors fall, corresponding industries in China face losses," Guan said.
The same goes for major Western economies closely connected to the world's supply chains. As for China, the world's largest soybean importer could see import prices jump if heatwaves were to damage the crop in the Americas and slash supplies, he added. This would have a knock-on effect on Chinese consumers.
A fast-warming world is setting carbon reduction targets, but governments should place equal emphasis on measures to adapt to climate change, Guan urged.
The world has just experienced the hottest January on record as climate change continues to push up temperatures. US scientists have said 2024 has a one-in-three chance to be hotter than last year, and a 99% chance of being one of the top five warmest years ever.
"Even if we limit global warming to below 1.5 degrees by the end of the century, the world will continue to be hit by increasingly frequent and severe climate extreme events in the coming decades," Guan said.
"Building a resilient international trade network is as important as reducing emissions."