Exposure to extreme heat is getting worse as a result of climate change

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UNTIL THIS summer Verkhoyansk, a village in Siberia, was famous for being the coldest inhabited place north of the Arctic circle, with a record low of −67.8°C. In June, however, it claimed another record: the hottest place north of the Arctic circle. The village recorded a high of 38°C, whereas the usual summer peak is around 20°C. The freak temperatures were made 600 times more likely by man-made climate change, according to the World Weather Attribution project, a collaboration among climate researchers. As greenhouse gas emissions in the atmosphere increase, extremes of heat such as that in Verkhoyansk are becoming more frequent. According to a new report in the Lancet, this is putting an increasing number of lives at risk.

A warming world poses many dangers, including flooding, pollution and the spread of disease, but the researchers identified heatwaves as one of the most striking. People already living in the hottest regions are the most exposed, but regardless of location, it is the elderly and those with pre-existing health problems such as heart disease who tend to suffer the most. The study combined population records with hourly temperature data from the European Centre for Medium-Range Weather Forecasts to track vulnerable people’s exposure to heatwaves.

Last year, people aged over 65 endured a combined extra 2.9bn days of extreme heat compared with a 1986-2005 baseline (see chart). This beats the previous record, set in 2016, by 160m days. India and China were among the worst affected, thanks to large populations and already hot regions. Heat-related deaths among the elderly, meanwhile, have risen by almost 54% between 2000 and 2018, according to the researchers’ estimates. In 2018, the most recent year for which figures are available, heatwaves killed around 296,000 people over 65. Again, China and India suffered the most, with 62,000 and 31,000 deaths, respectively. Germany and America were the worst-affected Western countries, suffering around 20,000 deaths each.

A hotter planet has other costs too. Last year 302bn working hours were lost to heatwaves, 103bn more than at the turn of the century, according to the study. India’s productivity suffered the most, in part because of its large agriculture industry. In 2018 India had the second-highest agricultural output of any country, after China, but little farmland is irrigated, and much production depends on the monsoon. In high-income countries, such as America, construction was the industry worst affected.

The paper’s authors note that climate change poses a similar, albeit less acute, challenge to health-care systems as covid-19 does. As extreme-weather events become more frequent, countries need to identify the most vulnerable groups and invest in health care to ensure hospitals are not overwhelmed by climate shocks. But, as with the pandemic, prevention would be preferable to treatment. That will be hard. This week a separate report by the World Meteorological Organisation found that 2020 will be one of the three warmest years on record, with average global temperatures of 1.2°C above pre-industrial levels. By 2024, that is expected to rise to 1.5°C.

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