Permafrost in the Arctic will release greenhouse gases at a slower rate than many climatologists previously believed, possibly averting a potential "carbon bomb" that had many scientists worried.
Global warming driven by human activities is thawing the Arctic permafrost, which releases greenhouse gases to the atmosphere. Concern has been expressed by researchers that if this release of gases is accelerated too quickly by human-driven climate change, the process could result in a runaway greenhouse effect.
Between 1,330 billion to 1,580 billion tons of organically derived carbon is trapped within the soil of the Arctic and subarctic, more than twice as much carbon as is present in the atmosphere. These greenhouse gases are derived from the remains of plants and animals over thousands of years, building deposits of methane, carbon dioxide, and other gases which could negatively impact the environment.
Decomposition of the materials and thawing of permafrost can release this carbon into the atmosphere, in a natural process which raises concentrations of greenhouse gases worldwide. Researchers are studying the process in an effort to determine how quickly these substances are being released, in a quest to predict how it could affect climate change.
Analysis of several previous studies suggests that Arctic regions will likely emit these trapped gases slowly, over the course of several decades. Some climatologists expressed concerns that the process could take place over just a few years, in a scenario which became known as a climate bomb.
This new examination brings to light the balance between human-driven and natural processes in the environment.
"Human activities might start something in motion by releasing carbon gases but natural systems, even in remote places like the Arctic, may add to this problem of climate change," Ted Schuur, a biologist with Northern Arizona University, said.
Temperatures in the Arctic have increased twice as fast as the global average over the last three decades, researchers have determined. This rate of warming has worried some researchers concerned with a runaway greenhouse effect.
"The permafrost carbon is not going to explode into the atmosphere catastrophically within just a few years. It's more like it will seep out slowly in small amounts in a very large number of places," Schuur said.
Even if a climate bomb is averted, these smaller emissions could add up to a significant contribution to global climate change, researchers warn.
Future analysis of the process will record how quickly the gases are emanating from the permafrost. Climate models will also be adapted to include newer databases, and differentiate between emissions of methane and other carbon-based gases.
Study of how thawing of the Arctic permafrost may occur, and how it could affect global climate change, was published in the journal Nature.
Photo: USGS | Flickr
