Fires of the North: Carbon emissions and climate implications of arctic and sub-arctic wildfires

Application summary

In recent years, unforeseen wildfires have spread northwards into arctic and sub-arctic regions as a consequence of progressive climate change. Northern fires release alarming amounts of carbon to the global carbon cycle, uniquely from deep, potentially ancient organic layers. Once seen as crucial carbon sinks, arctic and sub-arctic environments could shift to major carbon sources due to the ongoing changes in the northern fire regime. However, quantitative measurements of carbon emissions from alarmingly increasing arctic and sub-arctic fires are currently lacking and are thus urgently called for to determine the climate impact of these fires. My research aims to gather pioneering data on carbon emissions and their characteristics from increasing fires of the North. The main objectives are to estimate carbon losses, and to determine the age of carbon released in recent arctic and sub-arctic fires. We have conducted three field campaigns in Greenland and Canada, focusing on six recent wildfires. We assessed fire severity and conducted above- and below-ground measurements to calculate carbon losses. At these and additional two sites from Alaska and Estonia we also collected soil profiles to date the carbon released from these fires. This combination of carbon loss measurements and dating of released carbon is uniquely comprehensive and pioneering at arctic and sub-arctic fire sites. The results invaluably shed light on the changing role of northern environments in the global carbon cycle as a consequence of increasing fires. We produce critical input data on carbon emissions for global climate models, which are crucial to estimate the climate impacts of emerging arctic and sub-arctic fires. The results may inspire new fire abatement strategies to first target fires with highest climate warming potency. Furthermore, the results provide essential information for policymakers to prioritize climate change mitigation efforts at regional and global scales.