Study: Climate change significantly worsened Asia heat waves
Add Axios as your preferred source to
see more of our stories on Google.
Climate change has made extended heat waves that have enveloped large parts of Asia far more likely and intense, according to a new analysis.
Why it matters: Extreme heat, spanning Lebanon to the Philippines since April, is being blamed for hundreds of deaths. It's added to the suffering of people who lack access to air conditioning, including displaced persons in the Middle East, the study notes.
- The heat also led to crop failures in parts of South Asia, water shortages, and school closures for millions of children.
Zoom in: An international team of scientists affiliated with the World Weather Attribution effort examined peak heat periods in multiple regions, such as West Asia, including Israel, Syria, Lebanon and Jordan.
- They also zoomed in on maximum heat wave timeframes for South and Southeast Asia.
- Each of these areas has seen record-shattering temperatures in excess of 104°F (40°C) for days to weeks on end.
What they did: Using peer-reviewed methods, the researchers took observational data from surface weather stations and calculated how common such events are in today's climate.
- For example, in West Asia, they found that a heat wave of similar magnitude has a 10% chance of occurring in any given year.
- To simulate the effects of human-caused global warming of about 1.2°C (2.16°F) since the preindustrial era, the scientists used climate models to simulate such heat waves' occurrence and severity in today's climate compared to a world without added greenhouse gases.
- They also looked into the influence of a weakening but influential El Niño system in the equatorial tropical Pacific Ocean, which alters weather conditions around the world.
Yes, but: The researchers did not complete a full attribution analysis for parts of South Asia, including India, Bangladesh, Myanmar, Laos, Vietnam, Thailand and Cambodia.
- This is because weather observations from these heat waves showed that new climate model simulations would most likely closely match the conclusions of past climate attribution studies from 2022 and 2023.
- Those studies covered extreme heat events in much of the same area.
What they found: In West Asia, climate change made the heat about five times more likely and 1.7°C (3.06°F) hotter, the study concluded.
- In the Philippines, heat waves such as these are about 1-in-10-year events during El Niño years, but less common when that climate cycle is not present.
- Given its magnitude and longevity, the brutal heat in the Philippines, which set all-time national temperature records, would have been "virtually impossible" without human-caused climate change, the study found, even when accounting for El Niño.
Stunning stat: And in South Asia, 30-day heat waves on par with this have already become about 45 times more likely, and 0.85°C (1.53°F) hotter due to global warming, historical weather data shows.
- This lines up with previous attribution studies, which found that April heat waves in this region have become about 10 to 30 times more likely and about 1°C (1.8°F) hotter than in a preindustrial atmosphere.
Between the lines: This is the latest in a slew of rapid attribution analyses that seek to detect any human fingerprints in recent extreme events.
- The science in this area is rapidly advancing to the point where near-real-time attribution can be made for some weather variables, such as temperature.
- While they use peer-reviewed methods, the analyses themselves are not peer-reviewed yet. The group prioritizes releasing them when an extreme event is still salient in peoples' minds.
- However, much of the group's research — more than 70 studies to date — is then submitted for publication in scientific journals.
Reality check: The data found a significant link between the heat waves and climate change. But multiple investigations by the same organization and others have found that natural climate variability, including El Niño, played a bigger role in causing a highly impactful extreme event.
- This was the case, for example, with a recent attribution study on the Panama Canal drought.
What they're saying: "Climate change is bringing more days with potentially deadly temperatures to Asia every year," said Mariam Zachariah, a co-author of the study and researcher at Imperial College London.
- "Unless the world takes massive, unprecedented steps to reduce emissions and keep warming to 1.5°C, extreme heat will lead to even greater suffering in Asia."
