Simulation of Effects of Climatic Change on Fire Regimes

Abstract

Increasing concentrations of greenhouse gases in the atmosphere will likely be accompanied by substantial warming of the earth’s surface (1.5–4.5°C), altered precipitation patterns, and an increase in climate variability (Houghton et al. 2001). The impact of such climatic change on vegetation and fire activity is of great economic, social, and ecological interest across the globe. Plant species have evolved under a range of environmental conditions that have occurred in the past, including the timing and severity of fires, and some species may not be able to persist in a new climatic regime if the changes in environmental conditions exceed pre-adapted tolerances. Changes in plant species distributions brought on by global warming could seriously affect biotic diversity and ecosystem function (Peters and Lovejoy 1992). Of particular concern are changes in climate that result in an increase in the size, severity, or frequency of wildfires because the social and economic consequences of such changes are likely to compound existing management challenges (Arno and Brown 1991). For example, in western North America the accumulation of hazardous fuels due to decades of fire exclusion already poses serious threats to human life and property (Hardy et al. 1999; U.S. General Accounting Office 1999), and climate-mediated changes in the fire regime could serve to exacerbate the situation (Riggan et al. 1994). Changes in the size, severity, or frequency of fires could also have important ecological consequences such as changes in vegetation structure, species composition and native plant diversity (Christensen 1988; Brown 2000).