Wildfires across the western United States have been getting bigger and more frequent over the last 30 years – a trend that could continue as climate change causes temperatures to rise and drought to become more severe in the coming decades, according to new research.
The number of wildfires over 1,000 acres in size in the region stretching from Nebraska to California increased by a rate of seven fires a year from 1984 to 2011, according to a new study accepted for publication in Geophysical Research Letters, a journal published by the American Geophysical Union.
A satellite image of the 2011 Las Conchas Fire in New Mexico shows the 150,874 acres burned in magenta and the unburned areas in green. This image was created with data from the Monitoring Trends in Burn Severity (MTBS) Project that the authors of a new study used to measure large wildfires in the western United States.
Credit: Philip Dennison/MTBS
The total area these fires burned increased at a rate of nearly 90,000 acres a year – an area the size of Las Vegas, according to the study. Individually, the largest wildfires grew at a rate of 350 acres a year, the new research says.
“We looked at the probability that increases of this magnitude could be random, and in each case it was less than one percent,” said Philip Dennison, an associate professor of geography at the University of Utah in Salt Lake City and lead author of the paper.
The study’s authors used satellite data to measure areas burned by large fires since 1984, and then looked at climate variables, like seasonal temperature and rainfall, during the same time.
The researchers found that most areas that saw increases in fire activity also experienced increases in drought severity during the same time period. They also saw an increase in both fire activity and drought over a range of different ecosystems across the region.
“Twenty eight years is a pretty short period of record, and yet we are seeing statistically significant trends in different wildfire variables—it is striking,” said Max Moritz, a co-author of the study and a fire specialist at the University of California-Berkeley Cooperative Extension.
These trends suggest that large-scale climate changes, rather than local factors, could be driving increases in fire activity, the scientists report. The study stops short of linking the rise in number and size of fires directly to human-caused climate change. However, it says the observed changes in fire activity are in line with long-term, global fire patterns that climate models have projected will occur as temperatures increase and droughts become more severe in the coming decades due to global warming.
“Most of these trends show strong correlations with drought-related conditions which, to a large degree, agree with what we expect from climate change projections,” said Moritz.
A research ecologist not connected to the study, Jeremy Littell of the U.S. Geological Survey (USGS) at the Alaska Climate Science Center in Anchorage, AK, said the trends in fire activity reported in the paper resemble what would be expected from rising temperatures caused by climate change. Other factors, including invasion of non-native species and past fire management practices, are also likely contributing to the observed changes in fire activity, according to the study. Littell and Moritz said increases in fire activity in forested areas could be at least a partial response to decades of fire suppression.
“It could be that our past fire suppression has caught up with us, and an increased area burned is a response of more continuous fuel sources,” Littell said. “It could also be a response to changes in climate, or both.”
To study wildfires across the western U.S., the researchers used data from the Monitoring Trends in Burn Severity Project (MTBS). The project, supported by the U.S. Forest Service and USGS, uses satellite data to measure fires that burned more than 1,000 acres.
While other studies have looked at wildfire records over longer time periods, this is the first study to use high-resolution satellite data to examine wildfire trends over a broad range of landscapes, explained Littell. The researchers divided the region into nine distinct “ecoregions,” areas that had similar climate and vegetation. The ecoregions ranged from forested mountains to warm deserts and grasslands.
Looking at the ecoregions more closely, the authors found that the rise in fire activity was the strongest in certain regions of the United States: across the Rocky Mountains, Sierra Nevada and Arizona- New Mexico mountains; the southwest desert in California, Nevada, Arizona, New Mexico and parts of Texas; and the southern plains across western Texas, Oklahoma, Kansas and eastern Colorado. These are the same regions that would be expected to be most severely affected by changes in climate, said Dennison.
Notes for Journalists
Journalists and public information officers (PIOs) of educational and scientific institutions who have registered with AGU can download a PDF copy of this article by clicking on this link: http://onlinelibrary.wiley.com/doi/10.1002/2014GL059576/abstract
Or, you may order a copy of the final paper by emailing your request to Alexandra Branscombe at firstname.lastname@example.org. Please provide your name, the name of your publication, and your phone number.
Neither the paper nor this press release is under embargo.
“Large wildfire trends in the western United States, 1984-2011”
Philip E. Dennison: Department of Geography, University of Utah, Salt Lake City, Utah, USA;
Simon C. Brewer: Department of Geography, University of Utah, Salt Lake City, Utah, USA;
James D. Arnold: Department of Geography, University of Utah, Salt Lake City, Utah, USA;
Max A. Moritz: Department of Environmental Science, Policy, and Management, University of California, Berkeley, USA.
Contact information for the authors:
Philip E. Dennison: +1 (801) 742-1539, email@example.com
Max A. Moritz, firstname.lastname@example.org
+1 (202) 777-7516
University of Utah Contact
+1 (801) 581-8993
Peter Weiss | American Geophysical Union
Physics of bubbles could explain language patterns
25.07.2017 | University of Portsmouth
Obstructing the ‘inner eye’
07.07.2017 | Friedrich-Schiller-Universität Jena
Physicists working with researcher Oriol Romero-Isart devised a new simple scheme to theoretically generate arbitrarily short and focused electromagnetic fields. This new tool could be used for precise sensing and in microscopy.
Microwaves, heat radiation, light and X-radiation are examples for electromagnetic waves. Many applications require to focus the electromagnetic fields to...
Strong light-matter coupling in these semiconducting tubes may hold the key to electrically pumped lasers
Light-matter quasi-particles can be generated electrically in semiconducting carbon nanotubes. Material scientists and physicists from Heidelberg University...
Fraunhofer IPA has developed a proximity sensor made from silicone and carbon nanotubes (CNT) which detects objects and determines their position. The materials and printing process used mean that the sensor is extremely flexible, economical and can be used for large surfaces. Industry and research partners can use and further develop this innovation straight away.
At first glance, the proximity sensor appears to be nothing special: a thin, elastic layer of silicone onto which black square surfaces are printed, but these...
3-D shape acquisition using water displacement as the shape sensor for the reconstruction of complex objects
A global team of computer scientists and engineers have developed an innovative technique that more completely reconstructs challenging 3D objects. An ancient...
Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.
For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...
26.07.2017 | Event News
21.07.2017 | Event News
19.07.2017 | Event News
27.07.2017 | Materials Sciences
27.07.2017 | Life Sciences
27.07.2017 | Power and Electrical Engineering