Permafrost carbon could up global warming

BERKELEY, Calif., Aug. 24 (UPI) -- Global warming may accelerate as billions of tons of carbon trapped in permafrost moves into the atmosphere by the end of this century, U.S. researchers say.

Warming with climate change could cause soil in high-latitude regions to change from being a carbon sink, storing carbon dioxide, to a source of atmospheric CO2 by the end of the 21st century, computer modeling conducted by the U.S. Department of Energy's Lawrence Berkeley National Laboratory indicates.

The finding contradicts earlier studies that suggested climate change would spark a growth in high-latitude vegetation that would pull in more carbon from the atmosphere than thawing permafrost would release, a Department of Energy release said Monday.

The new model incorporates data on processes of how carbon accumulates in high-latitude soil over millennia and how it's released as permafrost thaws, and found the increase in carbon uptake by more vegetation would be overshadowed by a much larger amount of carbon released into the atmosphere.

"Including permafrost processes turns out to be very important," Berkeley Lab researcher Charles Koven said. "Previous models tended to dramatically underestimate the amount of soil carbon at high latitudes because they lacked the processes of how carbon builds up in soil."