How science links extreme weather disasters to climate change: Interview with WWA’s Clair Barnes

The rise of attribution science

Extreme weather events are becoming more frequent and severe across the globe. From deadly heatwaves in India to catastrophic floods in Europe, the question is no longer whether climate change is involved — but how much. Clair Barnes, a researcher with World Weather Attribution (WWA), explains how scientists now link individual disasters to a warming planet.

WWA is a coalition of climate scientists who specialise in real-time attribution studies. Their work aims to answer a simple but powerful question: Did climate change make this event more likely or more intense — and by how much?

Barnes says the process involves comparing climate models that simulate a world without human-caused emissions to the actual conditions we are experiencing. The difference tells researchers how much global warming influenced a particular storm, heatwave, or flood.

How attribution studies work

To determine climate change's role in a specific event, scientists first collect observational data — temperature records, rainfall measurements, wind speeds. They then run two sets of climate models: one representing the current climate, and another simulating a counterfactual world without greenhouse gas emissions.

“We compare the likelihood of the event occurring in both scenarios,” Barnes explains. “If the event becomes significantly more likely in the world with climate change, we can say that global warming played a role.”

The analysis often takes just a few days, allowing researchers to publish findings while the disaster is still fresh in public memory. This speed is crucial for policymakers and disaster response agencies.

Real-world examples of attribution

WWA has studied dozens of events worldwide. In 2023, the group found that the deadly heatwave in northern India and Pakistan was made about 30 times more likely due to climate change. Similarly, the devastating floods in Pakistan in 2022 were found to be 50% more intense because of global warming.

“For heatwaves, the signal from climate change is very strong,” Barnes says. “For floods and storms, it can be more complex, but we are seeing clear patterns.”

The research also highlights how even small increases in global temperature can have outsized impacts. A rise of just 1.2°C above pre-industrial levels has already made many extreme weather events more dangerous and destructive.

Implications for policy and public understanding

Attribution science is not just an academic exercise. It provides evidence that can be used in courtrooms, in climate litigation, and in national adaptation plans. Governments and insurance companies are increasingly relying on such studies to assess risk and allocate resources.

Barnes says the goal is to make climate risks tangible. “When people see that a specific flood or heatwave was made worse by climate change, it connects the abstract science to their lived experience.”

She also notes that attribution studies can help developing nations demand compensation from high-emitting countries — a key issue in global climate negotiations.

However, the science has limits. For rare events or regions with sparse data, the models may not provide clear answers. And attribution cannot predict exactly when or where the next disaster will strike.

What comes next for attribution science

As climate change accelerates, the demand for rapid attribution is only expected to grow. WWA is working to expand its coverage to more regions, including tropical cyclones and wildfires. Barnes says the team is also improving methods to account for compounding events, such as heatwaves followed by heavy rains.

The hope is that this research will push governments to cut emissions faster. “Every fraction of a degree of warming matters,” Barnes says. “Attribution shows us the cost of inaction.”

For now, the science is clear: Climate change is making extreme weather events more dangerous, and the world must prepare for a future where disasters are the new normal. The question remains whether policymakers will act on the evidence.