Western U.S. wildfires are likely to increase in the coming decades, according to a new tree-ring study that links episodic fire outbreaks in the past five centuries with periods of warming sea surface temperatures in the North Atlantic.
Warmer waters in the North Atlantic correspond with episodes of drought and subsequent fires in the West as shown by fire scars in annual tree rings studied by the researchers, said Dr. Thomas Kitzberger of the University of Comahue in Argentina, who led the study.
Colleagues included researchers from the University of Colorado at Boulder, the University of Arizona, the U.S. Forest Service and Rocky Mountain Tree-Ring Research Inc., a private lab in Fort Collins, Colorado.
The study linked increased prevalence of western wildfires in recent centuries with 60 year long sea surface temperature shifts of about one degree Fahrenheit in the North Atlantic Ocean.
Known as the Atlantic Multi-Decadal Oscillation, these changes are natural and have been occurring for at least the last 1,000 years.
Previous tree-ring studies have linked fires in different regions of western North America to drought associated with the warm El Ni