NEW YORK • Climate change will damage the economies of countries whether they are rich or poor, hot or cold, by the year 2100, economists said in a new report, dispelling the notion that impoverished, warm countries will suffer the most on a warming planet.
Researchers who examined data from 174 countries over 50 years found that persistent temperature changes above or below a country's historical norm adversely affected economic growth, regardless of how warm a country is.
The United States could see a 10 per cent loss in gross domestic product without significant change in policy.
"In the UK, we had the hottest day (ever) recorded a few days ago, and infrastructure came to a halt," Dr Kamiar Mohaddes, a co-author and professor of economics at Cambridge University, told the Thomson Reuters Foundation on Tuesday.
"Trains are not running, people are not coping, and therefore productivity and economic growth falls."
Research has often focused on short-term devastation to poor, warm countries, but the report suggested that wealth and cooler temperatures are no protection from climate change's economic toll if major policy changes are not adopted.
In a "business as usual" scenario where climate-change-causing greenhouse gas emissions are not drastically lowered, the average global temperatures will increase by 4 deg C by 2100.
That would bring more than a 7 per cent loss in world GDP per capita, said the study published on Monday by the US National Bureau of Economic Research, a non-profit economic research organisation.
The 2015 Paris Agreement, a global pact to fight climate change agreed to by nearly 200 countries, aims to keep the earth's temperature rise well below 2 deg C, striving for 1.5 deg C. But even that would require a radical reduction in climate-warming greenhouse gas emissions, a landmark United Nations report found last year.
The economists' research focused on the US due to its varied climates, and found that ignoring the Paris accord's goals would affect industries from manufacturing to agriculture, costing the US more than 10 per cent of its GDP per capita.
"The average American household will be poorer," Dr Mohaddes said, and noted that other indus-trialised countries could be similarly impacted.
Canada, which is warming twice as fast as the rest of the world, could expect a 13 per cent loss in income, while Switzerland could see a 12 per cent cut and India would see a 10 per cent GDP per capita drop. But adhering to the Paris Agreement goals could hold the loss in the US to under 2 per cent, the report said.
US President Donald Trump vowed in June 2017 to pull the US out of the international agreement, dealing a major blow to the effort to affect climate change.
The earliest that could happen is November next year.
The report also suggested that while some countries are likely to adapt to climate change, they are unlikely to act in time to ward off all the negative effects to their economies.
"We need to have much stronger mitigation," said Dr Mohaddes. "If we do commit to Paris, the losses are substantially lower. It is not too late."
Researchers from the universities of Cambridge, Southern California, Johns Hopkins, and the National Tsinghua University in Taiwan, as well as the International Monetary Fund, contributed to the report.