While Siberia may be one of the last expanses on Earth where human presence is relatively scarce, scientists are finding some surprising connections between humans and fires in these frigid, northern forests. Until now, most researchers assumed that lightning caused most of the fires that burned in Siberia. But a new study by NASA scientists and others used a NASA satellite to map where and when fires lit up over a three year period. The satellite showed that Siberian fires burned mostly near people.
The study looked at an area in Central Siberia covering a little less than 6 million square kilometers (2,317,000 square miles). The number of fires in these areas varied greatly from year to year. For example, in 2001, less than half a percent of the land, or about 27,000 square kilometers (10,420 square miles) caught fire and burned. In 2003, that number tripled to almost 1.4 percent, or roughly 81,000 square kilometers (31,270 square miles) of land. But for each of the three years between 2001 and 2003 where data were available, the study found that most of the fires occurred in areas near where people had changed the land cover with roads, rail lines, towns and cities, industrial areas and other features related to humans. In fact, roads were the man-made feature with the greatest link to fires, with 97 percent of all fires in 2003 occurring within 300 kilometers (186 miles) of a major road.
But, the researchers caution, the striking link does not yet prove that humans are causing these fires. For starters, most of the fires were detected in southern areas, where it is warmer and drier, and where more people live. In the northern part of Siberia, above 65 degrees north, the soil freezes for most of the year, and when it melts the ground is soggy. These conditions make it hard for both people and fires to survive. In the south, where summers are longer, drier and warmer, more fires would occur regardless of human presence. In order to find clearer answers to questions of how and whether or not humans may be contributing to fires, more studies are needed to examine cultural practices in the area and how they relate to fires.
Krishna Ramanujan | EurekAlert!
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