December 4, 2023

More than a third of heat-related deaths in many parts of the world can be attributed to the additional warming associated with climate change. This emerges from a new study that is taking decisive action to reduce greenhouse gas emissions in order to protect the public’s health.

The comprehensive new research, published Monday in the journal Nature Climate Change, was carried out by 70 researchers using data from large-scale projects in epidemiology and climate modeling in 43 countries. It found that warm season heat-related deaths were compounded by climate change by an average of 37 percent in a range of 20 percent to 76 percent.

Some previous studies have done similar analyzes for individual cities during specific heat waves, but the new paper applies these ideas to hundreds of locations and over decades to come to broader conclusions.

“It’s a thoughtful, insightful, and wise approach to understanding how climate change is changing heat-related mortality,” said Kristie L. Ebi, professor at the University of Washington’s Center for Health and Global Environment involved in the study.

The planet has already warmed by one degree Celsius in pre-industrial times, and much more severe warming is predicted with catastrophic consequences if global emissions of greenhouse gases such as carbon dioxide and methane cannot be brought under control.

“Taken together, our results show that a significant proportion of total and heat-related deaths during our study period are due to man-made climate change,” the authors wrote.

In many of the locations examined, the scientists found that “the attributable mortality rate from heat due to climate change is already on the order of tens to hundreds of deaths per year”. Climate change has increased all-cause mortality by up to 5 percent in some parts of the world for all reasons, the authors found. They found increased mortality from climate-induced heat on every inhabited continent.

While the differences in mortality between the locations studied are complex and arise from a variety of factors including access to health care as well as architecture, urban density, and lifestyle, the study indirectly suggests a separation between rich and poor regions. The researchers found that North America and East Asia tended to have lower rates of climate-related deaths. In some Central and South American countries, the proportion of heat deaths caused by warming was more than 70 percent.

While people around the world increasingly rely on air conditioning, which could lower the death rate while adding to the emissions that heat the planet, climate change is also disrupting power grids. In the US, failures have risen 60 percent since 2015 alone. This means that the air conditioning crutch could become less reliable over time.

Ana Maria Vicedo-Cabrera, lead author of the new paper and researcher at the Institute for Social and Preventive Medicine at the University of Bern in Switzerland, said the study showed that climate change is not just a problem for the future. “We see these climate change issues as something the next generation will face,” she said. “It’s something we’re already facing. We throw stones at ourselves. “

The future looks even bleak, she added. “That burden will increase,” she said. “Really, we have to do something.”

Dr. Ebi agreed. “Climate change is already affecting our health,” she said, noting that “essentially all heat-related deaths are preventable.” Much depends on choices, she said; Communities must adapt to heat through measures such as cooling centers and heat action plans to help those most at risk. She added, “In the long term, there are many opportunities that will affect our future vulnerability, including reducing our greenhouse gas emissions.”

Since scientists were unable to collect reliable data in some parts of the world, including parts of Africa and South Asia, Dr. Vicedo-Cabrera does not say that the mortality average established by the researchers could be applied globally. “This estimate that we received cannot be applied to areas that we have not assessed.”

These loopholes need to be closed, argued a comment published alongside the paper. “The countries where we do not have the health data we need are often among the poorest and most vulnerable to climate change and are also worrying as the main projected priorities for future population growth,” the comment said. “Obtaining this data will be vital to science in order to provide the information needed to adapt these countries.”

The author of the comment, Dann Mitchell, a climate researcher at the University of Bristol, said in an interview that the increasing burden of climate change aggravated heat waves in societies like India, where many people already live in overcrowded conditions and in poverty, where many people are already living in overcrowded conditions and poverty the health services are already strained, “something could emerge that is not sustainable”.

“It’ll crack at some point,” he said.