Long-term climate change impacts on fire, vegetation and permafrost in the Arctic are uncertain. Here, we show the high potential of organic compounds from low-temperature biomass burning to serve as proxies for surface fires in lake deposits. During warm periods of the last 430 000 years, surface fires are closely linked to the larch taiga forest with its moss–lichen ground vegetation that isolates the permafrost. They have reduced in warm–wet, spruce–dominated and cool–dry steppe environments.