London: As parts of the United Kingdom experienced extreme heat this summer, climate scientists say a commonly asked question, "Was this heatwave caused by climate change?", misses the bigger picture.
According to researchers, heatwaves have always occurred as a natural part of weather patterns, typically driven by persistent high-pressure systems. Climate change does not create heatwaves but makes them hotter, more frequent and more damaging by warming the atmosphere.
Scientists say the more relevant question is how much climate change has intensified a particular heatwave because greenhouse gases, primarily from burning fossil fuels, have accumulated in the atmosphere.
This is the basis of attribution science, a field that examines how climate change influences the intensity and likelihood of extreme weather events.
Researchers argue that every heatwave now develops in an atmosphere that is significantly warmer than it was a century ago because of increased greenhouse gas concentrations. As a result, today's heatwaves are hotter than they would have been in a world without human-driven warming.
In one study, researchers recreated the atmospheric conditions of the 1976 UK heatwave using today's climate. They found that peak temperatures would be around 3°C to 4°C higher, even though the underlying weather pattern remained unchanged.
According to the researchers, climate change does not determine whether a heatwave occurs. Instead, natural weather variability influences when a heatwave develops, while greenhouse gas emissions increase the likelihood that it will be more intense, break temperature records and cause greater impacts on health and infrastructure.
They say the same principle applies to other extreme weather events, including heavy rainfall, droughts and coastal flooding.
The researchers explained that the atmosphere responds to the concentration of greenhouse gases, particularly carbon dioxide released from burning coal, oil and natural gas. Every additional tonne of carbon dioxide increases atmospheric concentrations and raises the probability of more severe weather extremes.
They also argue that public discussions often focus on the broad term "human-caused climate change" rather than the underlying driver, fossil fuel emissions.
While individual actions such as reducing personal emissions remain important, the researchers say they are only part of the solution. They argue that burning fossil fuels accounts for around three-quarters of global greenhouse gas emissions and nearly 90 per cent of carbon dioxide emissions, making the transition away from fossil fuels central to limiting future warming.
They note that campaigns promoting personal carbon footprints helped increase public awareness but also shifted attention away from the larger challenge of transforming energy systems that rely on fossil fuels.
The researchers conclude that reducing emissions from electricity generation, transport, industry and heating systems is essential to slowing climate change. At the same time, they say governments and communities must strengthen infrastructure and improve resilience to the impacts of a warming climate that are already being experienced.
According to the researchers, heatwaves are expected to become hotter and more dangerous until greenhouse gas emissions stop accumulating in the atmosphere.