Although fire is ubiquitous in forest ecosystems, its role in driving forest cover change and climate feedbacks remains unclear at the global scale. Here we present an observation-driven assessment of fire-induced forest cover loss and its biophysical climate feedback. Our results show that fire-induced forest cover accounts for 14.8% of global forest cover loss, mostly in northern high latitudes. Forest fire increases mean annual land surface temperature by 0.153K (0.120-0.186K), with distinct seasonal and latitudinal patterns due primarily to reduced evapotranspiration and to a lesser extent decreased albedo. The positive climate-fire feedback is stronger in colder biomes, and controlled more by fire severity than burned area. Globally, mean forest fire-induced surface warming is equivalent to 62% of warming due to fire-related CO2 emissions. Our results show that positive climate feedbacks associated with forest loss due to fire may be more enhanced than those associated with forest loss due to human activity because of different biophysical controls, and underscore the necessity of separating human vs natural-disturbance to better understanding the biophysical response of forests to changing climate.

this seminar is part of the Missoula Fire Sciences Laboratory 2017-2018 Seminar Series.