Global climate projections have drastically underestimated carbon emissions from thawing permafrost in the Arctic, a new study suggests.
The study published in the peer-reviewed journal Nature Communications indicated that permafrost emissions could be more than double what has been projected because of the methane from thermokarst lakes, which form in permafrost, Alaska's Energy Desk reported Monday.
Scientists have previously projected that the Arctic could absorb as much or more carbon than emitted partly because of additional plant growth from warmer temperatures. Taking into account the thermokarst lakes, the projections of permafrost emissions in the later part of this century could increase by 118 percent, according to the study.
"If we take into account these lakes, we realize, 'Oh, we actually have a pretty significant source of permafrost carbon this century,'" said Katey Walter Anthony, the study's lead author and associate professor at University of Alaska Fairbanks.
The permafrost emissions could match emissions from land use change, like forest clearing and burning – the second-largest human source of emissions. If more carbon from permafrost is emitted, it could lead to greater warming.
"The models that we've used to construct these carbon budgets of how much CO2 we can emit and stay below a certain temperature threshold that we say is the edge of where things go from bad to really bad – those carbon budgets are probably made with models that are incomplete and may, in many ways, be very optimistic," said Charlie Koven, a scientist who works on climate models at Lawrence Berkeley National Laboratory in California.
Anthony's study calls for the broader climate models to start incorporating thermokarst lakes for a more comprehensive projection of emissions this century.