USA — Human behaviorfrom cigarettes tossed on the highway to electrical poles dotting the Santa Ana landscapeis as big a factor in driving the frequency of wildfires as climate change, according to a study lead by Assistant Professor of Geography Michael Mann. In an examination of Californias devastating blazes, Mann revealed that people are at least as dangerous as nature, and that tracking human activity can be a key factor in predicting fires frequency and locations as well as preventing their outbreaks.
Individuals dont have much control over how climate change will affect wildfires in the future, Mann said. However, we do have the ability to influence the other half of the equation, those variables that control our impact on the landscape.
The study, which was published in the online journal PLOS ONE, systematically looked at human behavior and climate change together, a type of review that rarely is attempted on an area of land the size of California. The findings suggest that previous models of wildfire predictions do not accurately account for human factors and could be misleading when identifying the main causesor driversof wildfires.
Each year, raging wildfires destroy thousands of acres of land, homes and lives. The staggering toll of destruction underscores the importance of predicting when and how wildfires occur.
Climate change affects the severity of the fire season and the amount and type of vegetation on the land, which are major variables in predicting wildfires. But humans contribute another set of influencing factors, including where structures are built and the frequency and location of ignitions from a variety of sourceseverything from carelessly throwing cigarette butts out car windows to stringing power lines over wooded areas to leaving campfires unattended. At the same time, the housing boom and enhanced government subsidies prompted a rush to build on the fire-prone edges of urban and natural systems. The result has been an incendiary combination: More people living in fire-hazard regions.
Many scientific models have either omitted the impact of human variables on California wildfires altogether or overstated the influence of climate change. But tracking human activity at the same rate as climate factors can predict the occurrence of costly wildfires while also offering a long-term forecast for preventing the blazes in the first pace, Mann said. Understanding where and how we build communities, for example, is essential to limiting future losses. As a result of the near-saturation of the landscape with human development, Mann estimated that people are responsible for igniting more than 90 percent of the wildfires in California.
We can reduce our risks by disincentivizing housing development in fire-prone areas, better managing public land and rethinking the effectiveness of our current firefighting approach, he said.
Between 1999 and 2011, California reported an average of $160 million in damages annually related to wildfires. That devastation by California wildfires could triple by 2050, reaching $500 million annually, Mann said. The fires destroyed nearly 13,000 homes and other structures in so-called state responsibility areasfire jurisdictions maintained by California. During this same period, California and the U.S. Forest Service spent more than $5 billion on wildfire suppression.
By proportionately accounting for both climate change and human behavioral threats, Manns model allows experts to more accurately predict how much land is at risk of burning in California through 2050about 7 million acres over the next 25 years, he estimated. According to Mann, this information is critical to policymakers, planners and fire managers to determine wildfire risks.