Fire must be accounted for as an integral part of climate change, according to 22 authors of an article published in the April 24 issue of the journal Science. The authors determined that intentional deforestation fires alone contribute up to one-fifth of the human-caused increase in emissions of carbon dioxide, a heat-trapping gas that increases global temperature.
The work is the culmination of a meeting supported by the Kavli Institute for Theoretical Physics (KITP) and the National Center for Ecological Analysis and Synthesis (NCEAS), both based at the University of California, Santa Barbara and funded by the National Science Foundation (NSF).
The authors call on the Intergovernmental Panel on Climate Change (IPCC) to fully integrate fire into their assessments of global climate change, and consider fire-climate feedbacks, which have been largely absent in global models.
The article ties together various threads of knowledge about fire, which have, until now, remained isolated in disparate fields including ecology, global modeling, physics, anthropology and climatology.
Increasing numbers of wildfires are influencing climate as well, the authors report. "The tragic fires in Victoria, Australia, emphasize the ubiquity of recent large wildfires and potentially changing fire regimes that are concomitant with anthropogenic climate change," said David Bowman of the University of Tasmania. "Our review is both timely and of great relevance globally."
Carbon dioxide is the most important and well-studied greenhouse gas that is emitted by burning plants. However, methane, aerosol particulates in smoke, and the changing reflectance of a charred landscape each contribute to changes in the atmosphere caused by fire. Consequences of large fires have huge economic, environmental, and health costs, report the authors.
The authors state, "Earth is intrinsically a flammable planet due to its cover of carbon-rich vegetation, seasonally dry climates, atmospheric oxygen, widespread lightning and volcano ignitions. Yet, despite the human species' long-held appreciation of this flammability, the global scope of fire has been revealed only recently by satellite observations available beginning in the 1980s."