Humans behind most wildfires in U.S. - study

PanARMENIAN.Net - People sparked most U.S. wildfires in recent decades, causing longer fire seasons and increasing the amount of scorched earth, AFP reports citing a new study published Monday, February 27.

Researchers found that humans caused 84 percent -- or four out of five -- of the total 1.5 million wildfires studied between 1992 and 2012.

Lightning accounted for the rest.

In addition, human actions tripled the length of the fire season during those two decades and were responsible for 44 percent of the total acreage burned, researchers reported in Proceedings of the National Academy of Sciences.

"Humans are expanding fires into more locations and environmental conditions than lightning is able to reach," said Bethany Bradley at the University of Massachusetts Amherst, a co-leader of the study.

The spike in wildfires was aggravated by rising urbanization, they said.

And the potential threat was expected to get worse. Places where houses are intermingled with natural areas are expected to double by 2030 from the current nine percent of all U.S. land area.

"Our results highlight the importance of considering where the ignitions that start wildfires come from, instead of focusing only on the fuel that carries fire or the weather that helps it spread," said co-lead author Jennifer Balch at the University of Colorado-Boulder.

"Thanks to people, the wildfire season is almost year-round."

The United States has suffered historically large wildfires in the past decade, especially in the western half of the country.

There is national concern about the duration and intensity of future wildfire seasons because of their potentially severe impact on agriculture, ecosystems, recreation and other economic sectors.

An additional worry is the high cost of putting out the blazes, which has topped $2 billion in recent years.