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Extreme heat can have large impacts on human health, and climate change is expected to lead to more and hotter heatwaves. Photo by Marcelo Leal on Unsplash.

Extreme heat can have large impacts on human health, and climate change is expected to lead to more and hotter heatwaves. Photo by Marcelo Leal on Unsplash.

A warmer world will cause more health problems

Climate news - News and opinions about climate science

Published 16.10.2018

Global warming can have detrimental effects on public health, as hotter weather increases air pollution and raises the risk of developing heart and lung diseases, scientists say.

Beer prices are likely to rise after this summer’s heatwave scorched harvests across large parts of Europe, leading to markedly higher barley prices, according to a recent report by investment bank Berenberg.

Over the next 80 years, more frequent extreme droughts and heatwaves could in fact lead to a doubling of average, global beer prices, which will result in a 16% decrease in global beer consumption, said a study published by Nature Plants on 15 October.

Climate change could thus potentially lead to people drinking less beer. Other positive health effects of a warmer, global climate are, however, few and far between, scientists say.

“Heat waves can have large impacts on human health, and prolonged, intense heat waves increase the health risks,” says Kristin Aunan, senior researcher at CICERO Center for International Climate Research.

This was experienced by health workers across the world this summer, with hospitals reporting that they had received thousands of patients with heat-related concerns, including dehydration, heatstroke symptoms and heart problems.

Heat waves can have large impacts on human health.

Kristin Aunan, senior researcher at CICERO.

2018 is on track to become one of the hottest years on record, with extreme heat, heatwaves and drought marking the summer in the northern hemisphere, according to the World Meteorological Organization (WMO).

Much of North America, Europe, North Africa, East Asia and the Middle East saw temperatures averaging 1-3°C above normal between May and July, the WMO said.

Elderly people most at risk

Some people are more at risk than others when it comes to developing health problems due to very hot weather.

“Certain groups of people, such as the elderly, young children, and people with certain diseases, are more prone to suffer under extreme heat,” Aunan says.

“With an aging population in many parts of the world, the pool of vulnerable people grows rapidly,” says the CICERO researcher.

Factors such as low socioeconomic status, poor housing and being socially isolated have also been shown to increase the risk of severe outcomes, she adds.

More wildfires and air pollution

The risk of wildfires increases during periods of extreme heat and low levels of precipitation. In addition to scorched harvests and failed crops in large parts of Europe, this summer’s heatwave also led to record numbers of wildfires raging through the Greek, Norwegian, and Swedish forests.

“Wildfires cause intense air pollution and studies have shown that exposure to particulate air pollution (PM2.5) from such fires is already an important contributor to mortality in Europe, says Aunan.

With heatwaves becoming more frequent, forest fires are also expected to become more common and intense, meaning that in the future, many more people worldwide will be exposed to the smoke that these fires produce.

Hot weather alone can also induce respiratory diseases because air pollution – especially surface ozone and particulate matter – tends to rise in populated regions on days with high temperatures and little wind, according to Aunan.

“These are two major air pollutants that increase the risk to human health, particularly when it comes to heart and lung diseases,” Aunan explains.

More deaths from heart problems

Several consecutive days of very hot conditions also increase the risk of dying from heart problems, according to Dan Atar, cardiologist at Norway’s Oslo University Hospital.

“Although the fact remains that there are more people dying during the winter due to cold weather than during the summer from cardiovascular disease – mainly strokes and heart attacks – studies have shown that heatwaves are associated with a higher frequency of deaths caused by heart problems,” Atar says.

The risk of dying from heart problems increases not only the hotter the weather is, but also with the duration of the heatwave, he adds.

“Researchers have found that the relative excess cardiovascular mortality after five consecutive days of 32°C is 16%, and jumps to 28% after six days,” says Atar.

Heatwaves are associated with a higher frequency of deaths caused by heart problems.

Dan Atar, cardiologist at the Oslo University Hospital.

More and hotter heatwaves in the future

“Climate change is expected to lead to more hot summers like the one experienced in many parts of Europe this year,” says Nathalie Schaller, senior researcher at CICERO.

In the project ClimateXL, she and other CICERO researchers have studied the connection between long-lasting heatwaves and persistent high-pressure systems – also known as atmospheric blocking.

Atmospheric blocking is a meteorological phenomenon that causes certain areas to experience similar weather for a prolonged period, and it can lead to long stretches of extreme heat in the summer or bitter cold in the winter.

“Summer heatwaves are often associated with persistent high-pressure systems that “block” the westerly flow of air masses and divert low-pressure systems – which usually bring rain – around it,” Schaller explains.

Climate change is expected to lead to more hot summers like the one experienced in many parts of Europe this year.

nathalie Schaller, senior researcher at CICERO.

“During the 2018 summer, an atmospheric blocking sat over Scandinavia and the British Isles for many weeks, where dry and hot conditions dominated, but at the same time, Iceland experienced one of its coolest and wettest summers ever, since it was in the path of the diverted low-pressure systems,” she says.

Atmospheric blocking will lead to heatwaves also in the future, and global warming will make these even hotter, according to Jana Sillmann, research director at CICERO.

“To avoid the worst heat and serious health impacts, we need to reduce our greenhouse gas emissions and be better prepared for future hot summers, for instance with suitable adaptation measures and early warning systems,” Sillmann says.

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