Video wrongly claims past disaster deaths show climate change isn't real | Fact check

Emperor penguins in Antarctica are at risk of "quasi-extinction" due to melting ice.

The claim: Decreasing natural disaster-related death counts show climate change isn't real

A Sept. 16 Facebook video (direct link, archive link) shows a person listing purported casualties of various past natural disasters. Many had death tolls in the thousands to millions, he said.

"Goofballs on the left are screaming, 'See! Climate change! Climate change,'" he says. '"But you know what? Natural disasters are not new. In fact, fewer people die from them now than ever before in world history."

The video is captioned: "By the Numbers: Climate Change Is NOT Real."

The video was shared more than 800 times in 10 weeks.

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Our rating: False

Multiple lines of evidence show Earth's climate is changing due to greenhouse gases released by human activity. Death counts are not an accurate measure of the number or severity of extreme weather events because they are influenced by several factors, including technology and physical infrastructure, according to researchers. And there is no record of disaster deaths that spans all of "world history."

Climate change is real, caused by human greenhouse gas emissions

Global warming, which is caused by human greenhouse gas emissions, has been detected by multiple independent climate agencies. Scientists have also documented the effects of this warming, which include glacial and polar ice melt as well as sea level rise.

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In addition to documenting the warming itself, researchers have long understood the physical process by which greenhouse gases delay the escape of heat into space and warm the planet, Josh Willis, a NASA climate scientist, previously told USA TODAY. These physical principles have been verified through observations and experiments.

Researchers can also tell that the excess CO2 build-up in Earth's atmosphere comes from burning fossil fuels because a type of carbon found in excess in atmospheric CO2 matches the type of carbon found in fossil fuels, Willis said.

Further, "the amount of warming we see matches what we expect based on the increased CO2 we've added," he said. "The timing of the warming matches the timing of the CO2 increase caused by people."

Natural hazards increasing due to climate change

In addition to melting polar ice, climate change is increasing the frequency and severity of certain types of extreme weather and other environmental hazards, according to researchers.

"As we burn greenhouse gases, we trap more heat in the atmosphere and the oceans, which amplifies the energy in (Earth's) systems, making extreme events more powerful and more frequent," Cascade Tuholske, a Montana State University geographer, told USA TODAY in an email. "Climate change is increasing the likelihood of both acute disasters − like heat waves and flash floods − and long-term hazardous conditions − like chronic heat exposure or long-term drought."

The video does not directly challenge this fact, but it implies it must not be true because of a purported decrease in disaster-associated deaths. However, disaster deaths don't necessarily change in line with the severity or number of disasters.

This is because the number of deaths associated with a given natural hazard is ultimately influenced by social factors and physical infrastructure that may have little to do with the event itself, according to researchers. For instance, technology improvements such as early warning systems and robust building engineering save lives during disasters, Sara McBride, a social scientist at Earthquake Science Center, told USA TODAY in an email.

Social, political and economic systems strongly influence disaster mortality, Tuholske said. Thus, mortality trends alone cannot show whether or not climate change is occurring.

"There is a difference between measuring the increase in the frequency, duration and intensity of climate-related disasters ... and the impacts ... these disasters have on humans," he said. "Even if comprehensive global data did exist on climate-related disaster impacts, like fatality rates − which it does not − demonstrating that impacts are decreasing over time does not show that climate-related disasters themselves are decreasing."

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Disaster mortality data inconsistent

While the video claims there are fewer natural disaster deaths now than "ever before in world history," reliable disaster mortality records are not actually available for all of "world history," according to Damien Delforge, a scientist at the Centre for Research on the Epidemiology of Disasters.

Delforge said that he was not familiar with any comprehensive disaster mortality database for events prior to 1900, though individual records of particularly high-impact events are available.

Even in more modern times, "discerning clear, unbiased trends in the health impacts of these disasters globally is ... challenging due to the lack of high-quality, unbiased impact data," he said.

One reason for this is that different areas may have different mortality reporting protocols. Some don't report mortality data at all, Tuholske said.

"Many countries today, especially in sub-Saharan Africa, do not track fatalities from any cause, much less disaster-specific deaths," he said.

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Disaster mortality trends can also be skewed by a small number of very high mortality events.

For instance, one analysis of more than 12,000 disasters that occurred between 1920 and 2020 showed a decrease in the number of disaster deaths over that timeframe, according to a Centre for Research on the Epidemiology of Disasters report.

However, Delforge said, "what drives the trend of the aggregated roughly 12,000 weather-related disasters is a marginal amount of disasters − 10 to 50 − of very high mortality impact, due to famines and the lack of assistance at these times and places."

If those events are excluded from the analysis, the data shows an increase in deaths, according to the report. But, due to other potentially biasing factors, the report's authors also cautioned against interpreting this alone as confirmation that disaster deaths are increasing.

USA TODAY reached out to the Facebook user who shared the post for comment but did not receive a response.

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This article originally appeared on USA TODAY: False claim disaster deaths show climate change not real | Fact check