Overview of forest fires in En-ROADS. Forest fires caused by global warming are shown on the En-ROADS graphs for "CO₂ Gross Emissions from Forests" and "Deforestation and Mature Forest Degradation–Area." 

Big messages:

• Climate change increases the amount of forest that burns each year. This is a reinforcing feedback loop—more warming leads to more emissions from forest fires which leads to more warming. However, this feedback loop is a relatively small part of overall emissions, compared to burning fossil fuels. Compare the smaller green area of CO₂ from land use (including climate-driven forest fires) in the “Greenhouse Gas Net Emissions by Gas” graph to the much larger gray area of CO₂ emitted by fossil fuels. 
• Forest fires have two main climate effects: they emit CO₂ and methane into the atmosphere from trees and soil, and they reduce the forest’s ability to absorb CO₂ for an extended period. The rust-colored wedge in the “CO₂ Gross Emissions from Forests” graph shows the CO₂ released from forest degradation caused by warming-driven forest fires. The yellow wedge of CO₂ emissions from deforestation in the graph includes deforestation caused by warming-driven forest fires. This graph does not include the net effect of the diminished carbon removal of the forest. 
• Strong climate policies that lower emissions can reduce the risk of more forest fires due to warming.
• There is significant uncertainty about how future warming will influence forest fires. The strength of the feedback between warming and increased fire activity is an area of active research. Use the “Increase in forest fires from warming” slider in the Assumptions to explore a range of plausible scenarios.

Key Dynamics:

• Forest fires are a type of wildfire. Most wildfires, however, are assumed to emit zero net CO₂ because they occur on grasslands, pastures, and farmland that grow back quickly after a wildfire. In contrast, forest fires lead to net CO₂ emissions because they reduce the forest’s ability to absorb carbon for an extended period because trees grow back much slower. 
• Afforestation and protecting forests from deforestation and degradation reduces temperature increase (by preventing carbon release and allowing forests to continue absorbing carbon), but also creates a larger area of forests that could be vulnerable to fires. Younger forests can be especially vulnerable to fires in a warming climate. 
• Some forest fires are so intense that they prevent the land from regenerating as forest, resulting in deforestation. Use the “Percentage of severe forest fires resulting in deforestation” slider in the Assumptions menu to adjust this estimate. 

Facilitator Tips:

• En-ROADS only shows forest fires driven by warming. Forest fires that are part of normal cycles are included in the model as part of the carbon cycle but not displayed in graphs. 
• Deforestation results in permanent loss of forested land. Degradation, on the other hand, describes the temporary damage to forests that results in regrowth. Carbon is emitted from the loss of biomass in plants and soils but is slowly removed as the forest regrows. Degradation controls in En-ROADS only affect mature forests (those older than 100 years). The red wedge in the “Deforestation and Mature Forest Degradation” graph shows the area of mature forest degraded by climate-driven forest fires. Degradation of younger forests is not shown in this graph. 
• Deforestation in En-ROADS includes deforestation from climate-driven forest fires as well as human activities. As a result, reducing the “Deforestation and mature forest degradation” or “Reduction in deforestation” sliders does not eliminate all deforestation, because some climate-driven forest fires still result in deforestation. 
•  Use the “Wildfire Danger Days from Warming” map to examine how the increase in global temperature leads to more days with a higher risk of wildfires in many regions. Wildfire risk is affected by local weather conditions, including humidity, precipitation, temperature, and wind. For example, compare the changes in wildfires danger days in the boreal forests of Canada and Russia to the Amazon.