Extreme hot and cold temperatures brought on by climate change are causing five million deaths per year, amounting to 9.4% of all human lives lost around the world between 2000 and 2019, according to a new paper in the journal Lancet Planetary Health.

While extreme cold is still a much more common cause of death than heat waves, that balance is already beginning to shift as the atmosphere warms, Bloomberg Green reports, citing the report by a research team from Monash University in Australia and Shandong University in China.

“In the long term, climate change is expected to increase the mortality burden” as heat waves kill more people, said Monash professor and report co-author Yuming Guo.

Asia accounted for more than half of the impact over the last two decades, the study found, with an average of 2.6 million heat- and cold-related deaths per year, followed by Africa with 1.2 million, China with one million, and Europe with 835,000. Over the 20-year span, cold-related deaths fell 0.5%, while heat-related mortality rose 0.2%.

“The last two decades were the hottest since the pre-industrial era with the 10 warmest years on record occurring during the period,” Bloomberg writes. Over that period, Europe had the highest per capita death toll due to heat exposure, while Sub-Saharan Africa saw the highest death rate from cold.