We can debate the reasons for it, but there is no question that over the last 40 years the average size of wildfires has increased. The data we collected from the National Interagency Fire Center when grouped by decade shows that the average size of fires between 1970 and 2009 has more than quadrupled.
Climate Central has also noticed this and issued a report about the change in fire activity over the last 42 years. Here are some highlights:
- The National Research Council reports that for every degree Celsius (1.8°F) of temperature increase, the size of the area burned in the Western U.S. could quadruple.
- For the last decade, compared to the 1970s, there were 7 times more fires greater than 10,000 acres and nearly 5 times more fires larger than 25,000 acres each year.
- Since the 1970s the average number of fires over 1,000 acres each year has nearly quadrupled in Arizona and Idaho, and has doubled in California, Colorado, Montana, New Mexico, Nevada, Oregon, Utah and Wyoming.
- The burn season is two and a half months longer than 40 years ago.
- Rising spring and summer temperatures across the West appear to be correlated to the increasing size and numbers of wildfires. Spring and summer temperatures have increased more rapidly across this region than the rest of the country, in recent decades. Since 1970, years with above-average spring and summer temperatures were typically years with the biggest wildfires.
In spite of this clear trend of increasing wildfires, Congress and the Administration have been reducing the budgets of the federal land management agencies, and have cut the number of large air tankers on exclusive use contracts by 80 percent since 2002, from 44 to 9. However, seven more air tankers may be added over the next year, bringing the total to 16. William Scott, a fire aviation expert who also has experience in the National Security Agency, thinks that terrorists could, and perhaps already are waging economic war inside the United State by starting wildfires which can cost the government and residents billions of dollars.
Thanks go out to Kelly