Sandy P. Harrison

　　School of Archaeology, Geography and Environmental Science, University of Reading, Whiteknights, reading, UK.

　　Wildfire is an important component of the Earth System that is tightly coupled with climate, vegetation, and biogeochemical cycling. Wildfires are widespread and frequently collide with human societies by inflicting losses of property or lives. Strategies to mitigate these conflicts and manage wildfire impacts on vegetation, carbon cycle and climate must be underpinned by an understanding of changes in future fire regimes that accounts for all the controlling factors. Fire is often expected to increase in a warming world, but this is largely based on extrapolating measures of “fire danger” that depend only on the weather and not on the state of the vegetation. Process-based models that account for the effects of climate change, increasing atmospheric CO₂, human population and land use on vegetation and fire regimes provide a more nuanced picture. Although projected changes in area burnt and carbon emitted strongly depend on the choice of future climate and land-use scenario, the general outline is becoming clear. The area burnt is projected to decline in most tropical regions, and to increase in most extratropical regions. Changes in pyrogenic emissions are decoupled from changes in area burnt. Area burnt generally declines with increasing population density; accounting for this effect is pivotal. However, as fire regimes change in response to future climate and environmental changes, conflicts between fire and people will increase at the urban-wildland and rural-wildland interfaces and will require careful management.