https://science.feedback.org/human-driven-climate-change-largely-responsible-last-50-years-worsening-fire-weather-western-north-america-new-study-shows/ With the *North American fire season* rapidly approaching, wildfires will soon ignite debates over what caused them to spread. Though there are many factors – one is becoming increasingly clear: *human-driven climate change.* A growing body of evidence supports this, and a new study just stacked on key evidence. On 17 May 2025, new insights were published about what’s driving fire weather – the hot, dry, and windy conditions that help wildfires start and spread – in Western North America. Fire weather in that region has been worsening for 50 years, and new findings suggest that human-driven climate change – distinct from natural changes – is effectively responsible for all of it. While the trend itself was already well-established, this study overcame a long-standing challenge scientists have encountered: how do we determine how much of this trend comes from natural changes vs. human-driven climate change? Researchers achieved this using a well-established technique called ‘optimal fingerprinting’ – used to identify human vs. natural influence – in a novel way by applying it at a regional scale to assess fire weather. But this is just one paper, so what’s its significance? To answer that question in a fair way, Science Feedback interviewed one of the paper’s authors, and three scientists with relevant expertise who were not involved in the study. The common ground between the four scientists? *All agreed that the paper applied well-established methods in a novel way, and the results reinforced scientists’ understanding of the ties between human-driven climate change and worsening fire weather in North America.*