One type of ecosystem projected for significant decreases by century's end are subtropical savannas in Africa, Australia, and elsewhere. These are projected to see fewer fires than they currently experience, the research suggests. This would lead to major ecological changes there, since frequent fires keep savannas savanna-like.
Previous studies largely have produced projections of changing fire risks for individual regions of the globe, such as the western US. This new study is a rare attempt at trying to gauge future changes to wildfire patterns globally as the climate warms, the research team says. The warming has been triggered and sustained by rising carbon dioxide concentrations in the atmosphere, increases researchers have traced to burning fossil fuels as well as by land-use changes.
The study applies to fires once the province of ecologists trying to gauge the effect of climate change on the future distribution of plants and animals, Dr. Moritz explains. It treats fire as an entity that has its own form of ecological requirements: fuel, fire-favorable climate patterns, and ready sources of ignition.
The researchers first gathered global wildfire data gathered by two satellites and spanning 11 years – from 1997 to 2007. They used the information to estimate wildfire probabilities for each of 14 different broad vegetations types, or biomes, around the world under climate conditions that existed at the time.
They then turned to 16 climate models to develop projections of the climate's likely trajectory. They applied the results from each climate model to their fire model separately to see how much convergence they might or might not show in the final results.
They also used an existing model for plant production as a way to see how the abundance of fuel for these biomes could change in a warming climate.
As for ignition sources, the third piece of a fire's "ecosystem," humans supply the latter with enough regularity to suggest ignition sources won't be a limiting factor for fires.
From these steps they estimated changes to fire risks for each of the biomes for two periods: a 30-year span starting in 2010, and another starting in 2070.