A blistering heatwave that has shattered temperature records across the western United States this week would have been "virtually impossible" without the influence of the climate crisis, according to a rapid analysis released by an international team of scientists. The unseasonably warm and dangerous conditions, with temperatures soaring up to 30F (17C) above average for March, have left millions of Americans from the Pacific coast to the Rockies baking under extreme heat warnings.
Scientific Findings on Climate Impact
The analysis, conducted by World Weather Attribution, a consortium of climate researchers, determined that the climate crisis, primarily driven by the burning of fossil fuels, has made such intense heatwaves four times more likely to occur over the past decade. Researchers examined a five-day period from 18-22 March, using weather data, forecasts, and climate model simulations to compare heat events in today's climate with historical norms.
Ben Clarke, an extreme weather and climate change researcher at Imperial College London and co-author of the study, stated, "These temperatures are completely off the scale for March." The findings indicate that even as recently as 2016, the current heatwave would have been milder, with temperatures about 1.4F (0.8C) cooler. In preindustrial times, the difference would have been even more stark, at approximately 4.7F (2.6C) cooler.
Record-Breaking Temperatures and Widespread Effects
Fueled by a high-pressure system in the atmosphere, the heat dome has broken temperature records in 140 cities stretching from California to Missouri, according to the Weather Channel. California, Nevada, and Arizona were under extreme heat warnings on Thursday, with more heat expected in the coming days. The mercury is forecast to continue rising in the southwest, with the heatwave creeping toward the plains and southern regions later this week.
By the end of the week, up to 100 cities could set all-time temperature records for March, with temperatures climbing as high as 30F (17C) above average. This unprecedented warmth has forced multiple ski resorts in California and the Tahoe area to close or reduce operations due to rapid snowmelt, impacting local economies.
Health Risks and Policy Implications
Heat is the deadliest form of extreme weather in the US, prompting weather officials to raise concerns about an increase in heat-related illnesses, particularly among vulnerable populations. Authorities have advised people to stay hydrated and remain indoors when possible to mitigate risks.
Friederike Otto, a climate science professor at Imperial College London who contributed to the study, emphasized, "These findings leave no room for doubt. Climate change is pushing weather into extremes that would have been unthinkable in a preindustrial world." She added, "In the US west, the seasons that people and nature were used to for centuries are disappearing, putting many, including outdoor workers and those without air conditioning, in danger. The threat isn't distant – it is here, it is worsening and our policy must catch up with reality."
The analysis underscores the urgent need for policy adjustments to address the escalating impacts of climate change, as extreme weather events become more frequent and severe.
