How Will Deforestation and Vegetation Degradation Affect Global Fire Activity?

Abstract

Globally, many parts of fire emissions are driven by deforestation. However, few studies have attempted to evaluate deforestation and vegetation degradation fires (DDF) and predict how they will change in the future. In this study, we expanded a fire model used in the Community Land Model to reflect the diverse causes of DDF. This enabled us to differentiate DDFs by cause (climate change, wood harvesting, and cropland, pastureland, and urban land-use changes) and seasonality. We then predicted the state of fire regimes in the 2050s and 2090s under RCP 2.6 and RCP 6.0 scenarios. Our results indicate that the area affected by global total fires will decrease from the current 452 to 211–378 Mha yr⁻¹ in the 2090s under RCP 6.0 and to 184–333 Mha yr⁻¹ under RCP 2.6, mainly due to socioeconomic factors such as population and economic growth. We also predict that DDF will decrease from the current 73 million hectares per year (Mha yr⁻¹) to 54–66 Mha yr⁻¹ in the 2090s under RCP 6.0 and 46–55 Mha yr⁻¹ under RCP 2.6. The main contributor to these decreases in DDF burned area was climate change, especially the increasing of precipitation. The impact of future land use change on future DDF was similar or slightly lower than present-day. South America, Indonesia, and Australia were identified as high-risk regions for future DDF, mainly due to the expansion of wood harvest and pastureland. Appropriate land and fire management policies will be needed to reduce future fire damage in these areas.

Plain Language Summary

Global fire activities are affected by climate, land use, and socioeconomic factors. In order to represent changes in future fire activity, we model worldwide burned area with a particular focus on land-use change and predict future changes. We find that total fires could decrease in the future. The most obvious factor is that socioeconomic change (i.e., population and GDP growth) will decrease future fire activity. Climate change might cause a reduction or increase in total fire. The impact of future land-use changes on fires is similar to that of present-day. The land use changes due to wood harvest in tropics and pasture expansion in temperate regions increased regional deforestation or vegetation degradation fires in future. And we expect that these land-use change will increase fires in South America, Indonesia, and Australia, suggesting the need for adaptation to reduce the impacts of fires in these regions.