Future emissions from Canadian boreal forest fires

Abstract

New estimates of greenhouse gas emissions from Canadian forest fires were calculated based on a revised model for fuel consumption, using both the fire fuel load and the Drought Code of the Canadian Forest Fire Weather Index System. This model was applied to future climate scenarios of 2×CO2 and 3×CO2 environments using the Canadian Global Climate Model. Total forest floor fuel consumption for six boreal ecozones was estimated at 60, 80, and 117 Tg dry biomass for the 1×CO2, 2×CO2, and 3×CO2 scenarios, respectively. These ecozones cover the boreal and taiga regions and account for about 86% of the total fire consumption for Canada. Almost all of the increase in fuel consumption for future climates is caused by an increase in the area burned. The effect of more severe fuel consumption density (kilograms of fuel consumed per square metre) is relatively small, ranging from 0% to 18%, depending on the ecozone. The emissions of greenhouse gases from all Canadian fires are estimated to increase from about 162 Tg·year–1 of CO2 equivalent in the 1×CO2 scenario to 313 Tg·year–1 of CO2 equivalent in the 3×CO2 scenario, including contributions from CO2, CH4, and N2O.