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Heatwaves cost poor countries the most, exacerbating inequality

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Washington (AFP) – Heat waves, intensified by climate change, have cost the global economy billions of dollars over the past 30 years, according to a study released Friday, with poor countries paying the heaviest price.

And these lopsided economic effects contribute to widening inequalities around the world, according to the research.

“So far, the cost of extreme heat due to climate change has been borne disproportionately by the countries and regions least responsible for global warming,” Justin Mankin, a professor at Dartmouth College and Dartmouth, told AFP. one of the authors of the study published in the journal Science Advances. “And it’s a senseless tragedy.”

“Climate change plays out in a landscape of economic inequality, and it acts to amplify that inequality,” he said.

Extreme heat events cost the global economy an estimated $16 trillion between 1992 and 2013, the study found.

But while the richest countries lost about 1.5% of their annual GDP per capita to heat waves, the poorest countries lost about 6.7% of their annual GDP per capita.

The reason for this disparity is simple: poor countries are often located closer to the tropics, where temperatures are warmer anyway. During heat waves, they get even hotter.

The study comes days before the start of the COP27 climate summit in Egypt, where the issue of compensation for countries that are disproportionately vulnerable but least responsible for climate change is expected to be one of the key topics.

The costs of heat waves come from several factors: effects on agriculture, pressures on health systems, less productive labor and physical damage to infrastructure, such as melting roads.

“Cost of inaction”

Researchers in the study looked at five days of weather considered extreme for a specific region each year.

“The general idea is to use the variation in extreme heat, which is effectively randomly assigned to all of these economic regions, and see to what extent that explains the variation in economic growth” in a given region, explained Mankin.

“Then the second part is to say, ‘ok, how has human-caused warming influenced the extreme heat?'” he added.

Despite these calculations, the study results almost certainly underestimate the true cost of oppressive heat, according to the article – studying just five days a year does not reflect the increased frequency of such heat episodes, and all the costs potentials were not included.

Previous studies on the subject have focused on heat costs for specific sectors, though scientists say it’s important to look at the price of climate change holistically.

“You want to know what those costs are, so you have a baseline against which to compare the cost of action,” Mankin said, like establishing cooling centers or installing air conditioners, versus the ” cost of inaction”.

“The economic dividends of responding to the five hottest days of the year could be quite significant,” he said.

But according to Mankin, the most important answer is to reduce carbon emissions to slow global warming at the source.

“We need to adapt to the current climate, and we also need to invest deeply in mitigation,” he said.