Climate change and disruptions to global fire activity

Authors

  • Max A. Moritz,

    Corresponding author
    1. Department of Environmental Science, Policy, and Management, University of California, Berkeley, California 94720 USA
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  • Marc-André Parisien,

    1. Department of Environmental Science, Policy, and Management, University of California, Berkeley, California 94720 USA
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    • Present address: Natural Resources Canada, Canadian Forest Service, Edmonton, Alberta T6H 3S5 Canada.

  • Enric Batllori,

    1. Department of Environmental Science, Policy, and Management, University of California, Berkeley, California 94720 USA
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  • Meg A. Krawchuk,

    1. Department of Environmental Science, Policy, and Management, University of California, Berkeley, California 94720 USA
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    • Present address: Department of Geography, Simon Fraser University, Burnaby, British Columbia V5A 1S6 Canada.

  • Jeff Van Dorn,

    1. ATMOS Research and Consulting, Lubbock, Texas 79490 USA
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    • Present address: Department of Bioengineering, University of California, San Diego, California 92093 USA.

  • David J. Ganz,

    1. The Nature Conservancy, Berkeley, California 94720 USA
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    • Present address: Lowering Emissions in Asia's Forests (LEAF), Bangkok, Thailand 10500.

  • Katharine Hayhoe

    1. ATMOS Research and Consulting, Lubbock, Texas 79490 USA
    2. Climate Science Center, Texas Tech University, Lubbock, Texas 79409 USA
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  • Corresponding Editor: J. Elith.

Abstract

Future disruptions to fire activity will threaten ecosystems and human well-being throughout the world, yet there are few fire projections at global scales and almost none from a broad range of global climate models (GCMs). Here we integrate global fire datasets and environmental covariates to build spatial statistical models of fire probability at a 0.5° resolution and examine environmental controls on fire activity. Fire models are driven by climate norms from 16 GCMs (A2 emissions scenario) to assess the magnitude and direction of change over two time periods, 2010–2039 and 2070–2099. From the ensemble results, we identify areas of consensus for increases or decreases in fire activity, as well as areas where GCMs disagree. Although certain biomes are sensitive to constraints on biomass productivity and others to atmospheric conditions promoting combustion, substantial and rapid shifts are projected for future fire activity across vast portions of the globe. In the near term, the most consistent increases in fire activity occur in biomes with already somewhat warm climates; decreases are less pronounced and concentrated primarily in a few tropical and subtropical biomes. However, models do not agree on the direction of near-term changes across more than 50% of terrestrial lands, highlighting major uncertainties in the next few decades. By the end of the century, the magnitude and the agreement in direction of change are projected to increase substantially. Most far-term model agreement on increasing fire probabilities (∼62%) occurs at mid- to high-latitudes, while agreement on decreasing probabilities (∼20%) is mainly in the tropics. Although our global models demonstrate that long-term environmental norms are very successful at capturing chronic fire probability patterns, future work is necessary to assess how much more explanatory power would be added through interannual variation in climate variables. This study provides a first examination of global disruptions to fire activity using an empirically based statistical framework and a multi-model ensemble of GCM projections, an important step toward assessing fire-related vulnerabilities to humans and the ecosystems upon which they depend.

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