What ancient stalagmites can tell us about life on a hotter Earth

Stalagmites that formed in caves hundreds of thousands of years ago preserve a record of how fires behaved the last time Earth’s temperatures were as high as they are today. New Scientist environment reporter James Dinneen joined researchers on a descent into a cave in Oregon Caves National Monument and Preserve, part of their efforts to identify palaeofire signals in the fire-prone forests of the Pacific Northwest and to use cave records of wildfires to extend our view of fire activity hundreds of thousands of years ago, a time when temperatures on Earth were even hotter than now. That, in turn, is providing a fresh look at how we can expect future wildfires to behave as a result of climate change this century.