Wildfires and heat waves have been plaguing the states of California and Arizona this year. Since 2010, about 6.4 million acres have been burned on average per year. This is an increase of 3.5 million acres in the 1980s. Recent studies have stated that global warming is the cause of these wildfires and higher temperatures, and that the incidence of these natural disasters is likely to increase.
One reason that wildfires caused by climate change have such dramatic effects on the environment is that they act as part of a positive feedback loop with global warming. As temperatures increase, wildfires become more prevalent, which contribute carbon to the atmosphere. As this cycle progresses, climate change and wildfires both increase in frequency and severity.
Mega-fires, which occur when multiple wildfires combine together to form a larger, deadlier blaze, are also developing at higher frequencies as a result of global warming. The size of mega-fires makes containment more difficult. Firefighters use techniques like back-burning to help prevent further spread of these fires, but these measures are not always effective.
Some factors that promote wildfires, such as drought and insect outbreaks, have been linked to global warming as well. Insects that kill trees and other plants make the remains more susceptible to fires, as the plant matter dries out and can more easily be ignited. The conditions created by climate change are more optimal for insects, such as the mountain pine beetle, which has a faster life-cycle in warm conditions. Higher temperatures that result from climate change cause more water to evaporate from reservoirs and lakes, which can lead to drought.
With global warming causing higher temperatures, the wildfire seasons of affected areas lengthens. This occurs because summer heat begins to build earlier in the year, and the cooling fall season is delayed. For forests in the southwest United States, the conclusion of snowmelt indicates the time when fires are able to start. Climate change has caused the melting of snow to occur earlier than it did 50 years ago by about one to four weeks.
As temperatures increase, so does the incidence of lightning, which is notorious for starting fires in dry climates. It is estimated that an increase in temperature by 1.8 percent will lead to a 6 percent increase in lighting. As the conditions in wildfire prone areas become drier as well, there will be more dry material for fires to start off of.
The global warming trend has hit Southern California extremely hard, and the months of January through April have been hotter this year than they have been for any others in recorded history. This has also caused a drought which has been severe or worse for the entire state. Last year, drought affected only 46 percent of California. Philip Dennison, an author of one of the recent studies, stated that the extreme drought conditions will definitely cause a greater number of wildfire incidents.
With the results from these recent studies, global warming has been linked to an environment that promotes wildfires, by creating higher temperatures and causing drought. California’s wildfire season is just starting, and the damages are likely to escalate as the season continues.
By Joseph Chisarick