Scientists have warned that the recent increase in the incidence of wildfires in Alaska is contributing to the amount of stored carbon in forests, which could end up exacerbating the impact of global warming on the environment.
According to the U.S. Geological Survey (USGS), the widespread conflagration in Alaskan territories has destroyed large parts of tundra, permafrost and carbon-rich boreal forests that serve as nature's buffers against the effects of climate change.
A. David McGuire, a researcher from the agency, explained that high amounts of soil and biomass carbon have been stored in Alaska over the years as a result of cold temperatures.
They are concerned about how certain factors, such as the thawing of permafrost, the changing of the steam flow, the warming of temperatures and the increasing incidence of wildfires, would impact the stored carbon in the forests as well as the exchange of greenhouses gases in the region.
Current estimates show that 53 percent of all the carbon in the United States is absorbed by vegetation and soils in Alaska. The state is also responsible for absorbing as much as 3.7 metric tons of carbon from Earth's atmosphere every year.
A study by the USGS indicated that Alaskan wildfires typically burn areas twice as large as those lost in similar fires in the other lower 48 U.S. states. They also produce higher levels of greenhouse gas emissions than all other wildfires in these other states combined.
Scientists believe massive wildfires, such as those seen in Canada and northern U.S. states, would occur at a much higher rate in the next few decades as the world becomes increasingly warmer because of climate change.
Wildfires in northern areas are now considered to be a significant contributor to the worsening of global warming and no longer a by-product of it.
"This is one of the surprises that we haven't talked about much," Virginia Burkett, a climate expert from the USGS, said. "It has tremendous implications for the carbon that is locked up in Alaska soils and vegetation."
Burkett said USGS scientists discovered that the balance between the amount of stored carbon and the ones that are released was strongly connected to occurrence of wildfires in Alaska. They also found that during years of high wildfire incidence, the balance of stored carbon was reduced significantly. It would start to build up again only when the wildfires have subsided.
Wildfires cause the stored carbon in soils and forests to be released into the atmosphere and the carbon-rich layer of permafrost to be exposed.
Scientists believe carbon deposits in high latitude ecosystems, such as those in Alaskan forests, are more vulnerable compared with those in more temperate ecosystems.
As Burkett explains, this is because average temperatures in arctic and boreal regions are expected to increase at a much faster rate over the course of the next few years. This new projection reveals that the soil carbon releases in Alaska are magnified by wildfires in the state, which have become increasingly larger and more frequent as the climate in the Arctic continues to warm.
Photo: U.S. Fish and Wildlife Service Southeast Region | Flickr
