A study just published by The Lancet Planetary Health journal found that nearly 5.1 million extra deaths a year can be attributed to the global effects of climate change.
The international study, led by scientists from Monash University, is the first to examine global data and definitively link abnormal hot and cold temperatures caused by climate change to annual increases in mortality.
When examining global data from 2000 t0 2019, researchers say they found that 9.43% of global deaths could be attributed to abnormal cold and hot temperatures. The recent figure is significantly higher than the second-largest international climate mortality study published in 2015, which found that across 13 countries/regions, abnormal temperatures accounted for an estimated 7.7% of deaths.
Researchers say the problem with previous climate mortality research is that studies only examined a single country or region.
“This is the first study to get a global overview of mortality due to non-optimal temperature conditions between 2000 and 2019, the hottest period since the Pre-Industrial era,” said Monash University Professor and lead author of the study, Dr. Yuming Guo, in a press release.
“Importantly, we used 43 countries’ baseline data across five continents with different climates, socioeconomic and demographic conditions and differing levels of infrastructure and public health services, so the study had a large and varied sample size, unlike previous studies.”
Examining the temperature data over the last two decades, researchers found that global temperatures rose by 0.26 Celsius or .32 degrees Fahrenheit. While this change may seem minuscule, researchers say during this same period, heat-related deaths increased .21%, while cold-related deaths decreased .51%.
Because of the reduction in cold-related deaths, overall statistics show a net decrease in global temperature-related deaths. Researchers, however, caution this reduction of weather-related fatalities is deceptive.
“[Global warming may] slightly reduce the number of temperature-related deaths, largely because of the lessening in cold-related mortality, however in the long-term, climate change is expected to increase the mortality burden because hot-related mortality would be continuing to increase,” said Dr. Guo.
The study found that heat-related deaths increased across all global regions, leading researchers to sound the alarm that global warming due to climate change will cause temperature-related mortality rates to worsen.
Analysis of the data found that Eastern Europe and Sub-Saharan Africa currently have the highest temperature-related excess mortality rates. The most significant decline in net morality was found in Southeast Asia, while researchers say there was a “temporal increase in South Asia and Europe.”
More than half the global deaths related to non-optimal temperatures occurred in Asia, particularly in East and South Asia.
Europe had the highest death rates per 100,000 due to heat exposure.
Sub-Saharan Africa had the highest death rates per 100,000 due to exposure to cold.
“[The study shows] the importance of taking data from all points of the globe, in order to get a more accurate understanding of the real impact of non-optimal temperatures under climate change,” said Dr. Guo.
“Understanding the geographic patterns of temperature-related mortality is important for international collaboration in developing policies and strategies in climate change mitigation and adaptation and health protection.”