Long after the flames have gone out, the effects of large, climate-fuelled wildfires endure in Canada’s boreal forest, making the ground warmer than normal more than a decade later, a study shows. The new research, in the journal Nature, looked at the world’s northern latitude forests, using satellite data and on-site observations to measure surface temperatures in the years after fire events. Concluding, the larger the fire, the longer those warmer temperatures lingered. “We found a widespread warming effect one year after the fire events,” said Xianli Wang, co-author and a fire research scientist at the Canadian Forest Service. “14 years of data shows the residual effects even last that long.” After large fires the burned areas are left blackened, reducing how much sunlight and heat is reflected, akin to an urban heat island in the middle of the forest.