How science links extreme weather disasters to climate change: WWA interview

When a heatwave scorches a region or a flood submerges a city, a common question emerges: Was this caused by climate change? For Clair Barnes, a researcher with World Weather Attribution (WWA), the answer is rarely a simple yes or no. Instead, her work focuses on quantifying how much climate change altered the odds and intensity of such events.

In an interview with Mongabay, Barnes explained the mechanics of extreme event attribution. WWA, an international collaboration of climate scientists, has developed methods to analyse weather disasters as they unfold, often producing peer-reviewed studies within weeks.

The mechanics of attribution

Attribution science relies on two key tools: historical weather observations and climate models. Scientists compare the frequency and strength of an event in today's climate — which has warmed by roughly 1.2°C since pre-industrial times — with a simulated world without greenhouse gas emissions.

“We look at how rare an event would have been in a world without climate change and how rare it is now,” Barnes said. If a heatwave that would have occurred once in 50 years now happens every 10 years, that shift is attributed to human-caused warming.

This approach does not claim climate change 'caused' a storm or drought. Instead, it calculates the increase in probability. For example, WWA found that the devastating 2023 Libyan floods were made up to 50 times more likely by climate change.

Speed and relevance

Traditional climate studies can take years. WWA's rapid attribution framework compresses that timeline to weeks, enabling real-world use. Disaster response agencies, insurers, and governments now use these findings to assess risk and plan infrastructure.

Barnes noted that attribution results are also entering courtrooms. Citizens and local governments suing fossil fuel companies or demanding stronger climate policies increasingly cite attribution studies to link specific damages to emissions.

“We are not advocates,” she clarified. “We just provide the numbers. But those numbers are powerful in showing how climate change loads the dice for extreme weather.”

Limitations and future work

Attribution works best for heatwaves and heavy rainfall. For complex events like tropical cyclones or wildfires, factors such as wind patterns and land management complicate the analysis. WWA continues to refine its models for these cases.

Another limitation is data availability. Developing countries often lack the long-term weather records needed for robust attribution. Barnes stressed that WWA collaborates with local meteorologists to fill these gaps.

The field is also expanding to include compound events — multiple extremes occurring simultaneously or in quick succession, such as a drought followed by a heatwave.

As attribution science matures, its findings are expected to play a larger role in international climate negotiations and in setting national adaptation priorities. The link between extreme weather and climate change is no longer a theoretical projection. It is a measurable, present-day reality.

For now, WWA continues to monitor disasters globally. The next heatwave or flood could be the subject of their next rapid study — and the results will likely shape how the world understands its changing climate.