Half a Million People Killed in Deadliest Weather Disasters Since 2004

More than half a million people were killed in 10 disasters that climate change worsened, according to a new report.

Two weeks before world leaders meet to debate the climate crisis, a report released on Thursday shows the 10 deadliest extreme weather events in the past two decades were made worse by burning fossil fuels.

More than half a million people around the world were killed in those disasters since 2004.

“Many people now understand that climate change is already making life more dangerous,” said Friederike Otto, a senior lecturer at Imperial College London and co-founder of World Weather Attribution, the group that published the report. “What did not work yet is turning knowledge into action on a large-enough scale.”

Even with the abundance of evidence on how a warming world is endangering human life, the world keeps burning fossil fuels: 2023, the hottest year on record, also set a record for greenhouse gas emissions.

The stakes are high for how the world will respond in November, with a pivotal U.S. election and an annual climate summit of world leaders, known as COP29, hosted in Azerbaijan. Developing countries, hit hard by climate disasters, are pressing for rich countries to make good on their pledges to curb emissions and fund climate adaptation projects.

“The U.S. and really the world face a very sharp fork in the road,” said Michael Gerrard, a professor of environmental law at Columbia Law School.

Next week, the United States, the highest per-capita emitter of greenhouse gas emissions in the world, will vote on its climate future. A Kamala Harris presidency could continue the work of the Biden administration in transitioning to renewable energy, largely through tax credits and increased American manufacturing on clean energy technologies.

If returned to office, Donald J. Trump could roll back environmental regulations, including those that limit greenhouse gases, and continue development of fossil fuels. He could also pull out of international agreements to fight climate change, as he did in his first term as president.

“It will be extremely difficult for the world to take on the climate crisis if Trump is president of the United States,” said Lena Moffitt, executive director for Evergreen Action, a climate nonprofit.

A week after the Election Day, the world’s leaders will meet at COP29. In Azerbaijan, a tiny petrostate on the borders of Russia and Iran they will seek to agree on how to lower global emissions fast enough that temperatures remain below 1.5 degrees Celsius, or 2.7 degrees Fahrenheit, above preindustrial levels.

But the planet has already warmed 1.3 degrees Celsius, or 2.3 degrees Fahrenheit, since rich countries began burning fossil fuels like coal, oil and gas on an enormous scale. The world may now be on track to reach 3 degrees Celsius of warming by the end of the century, according to Dr. Otto and other climate scientists.

Last year, summit attendees pledged to transition away from fossil fuels, but the pact came with heavy caveats. Dr. Otto said she hoped this year’s conference would create a stricter timeline for that transition that could hold countries accountable.

The group of nations also set up a damages fund to help poorer countries with historically low emissions adapt to climate change. The fund, which currently has about $700 million pledged, is dwarfed by the hundreds of billions of dollars in climate-related damages developing countries may incur by 2030.

“It’s a ridiculously and insultingly low sum of money to help the most vulnerable countries with dealing with the losses and damages,” Dr. Otto said. “That needs to be orders of magnitude bigger.”

The new study showed that death tolls from extreme weather events are often higher in poor countries. Researchers culled the list of weather episodes from the International Disaster Database, and included three tropical cyclones, four heat waves, two floods and a drought. They noted that the high death toll was “a major underestimate,” with potentially millions of unreported heat-related deaths not included.

Europe faced well-documented heat waves in 2015, 2022 and 2023 that led to almost 94,000 deaths. Another report released this week shows that during a 2022 heat wave in Europe that caused 68,000 deaths, more than half of those deaths could be traced back to human-induced climate change.

But poor countries suffered more in extreme weather. In Somalia, a 2011 drought made worse by rising temperatures that sucked water vapor from plants led to 258,000 deaths; in Myanmar, Cyclone Nargis formed in 2008 over warmer seas and most likely had higher wind speeds and more intense precipitation as a result of climate change. It killed more than 138,000 people.

Climate attribution studies are now 20 years old, and more than 500 have been published by researchers. The first was published in 2004, according to World Weather Attribution; it showed that the likelihood of Europe’s 2003 summer, the hottest the continent had seen since 1500, was doubled by climate change.

To make such assessments, scientists pair weather observations with climate models and work with local experts and meteorological agencies.

Attribution studies can help raise awareness of climate change, but researchers have a hard time finding funding, said Michael Wehner, a senior scientist in applied mathematics at the Lawrence Berkeley National Laboratory.

“We have the technology and we have the methodology and the machines, the data and the experts,” Dr. Wehner said. “But they’ve got to be paid to do this, and they’re not.”

In its report, World Weather Attribution highlighted the need for protecting vulnerable people, improving early warning systems, and strengthening infrastructure like homes from flooding events, before the world reaches its limit for resilience.

But some events are now so extreme, experts warned, that governments could reach the limits of adaptation, underscoring the need to try to curb global warming as quickly as possible.

“Climate change has already made life incredibly hard and really dangerous, and we’re only at 1.3 degrees of warming,” said Joyce Kimutai, a researcher at Imperial College London. “We’re likely to see an escalation of impacts and the continual suffering of vulnerable people.”

Our Coverage of Climate and the Environment

• Climate F.A.Q.: Do you have questions about climate change? We’ve got answers.
• How Are the World’s Trees Doing?: More than a third of the world’s tree species are threatened with extinction, according to the first comprehensive assessment of trees by the world’s leading scientific authority on the status of species.
• Britain Tries to Green Its Grid: A utility sends phone alerts when wind power is cheap. A builder sells “zero bill” houses. They’re among several experiments to redefine how people value electricity.
• Heat Waves of the Future: Growing research suggests that humans may be more vulnerable to rising temperatures than scientists had previously believed.
• Ask NYT Climate: How bad are gas stoves for your health? They emit harmful pollutants, which makes good ventilation crucial.