Human-caused climate change is altering snow cover in the Arctic; some regions with more, some with less. Using the longest snow manipulation experiment in Arctic Alaska, new research led by UArctic Research Chair, Jeff Welker of the University of Oulu (UOulu) and Dr. Claudia Czimczik of the University of California, Irvine, report that deeper snow, has led to permafrost thaw and thus the release of ancient C into the modern atmosphere. This amplification of C emissions taking place throughout the year may accelerate the progressive increase atmospheric CO2 levels, global warming and changes in weather and climate of the north and beyond.
This research uses Welker’s long-term International Tundra Experiment (ITEX) research program in Arctic Alaska funded continuously by the National Science Foundation. “This is the first study to directly measure and ages (using 14C isotope techniques) mobilized ancient carbon emissions year-round. And, it shows that deeper snow, a realistic climate scenario, and currently being observed in many stations around the Arctic, has the potential to relatively quickly mobilize carbon deep in the soil, that was previously frozen for thousands of years” said Jeff Welker a Professor in the Ecology and Genetics Research Program at UOulu.
“This study is the culmination of over 20+ years of research at this site by my ITEX program. We first reported in 1998 that these Arctic exhibited measurable amounts of CO2 being emitted from these landscapes through the snowpack, an observation that stunned some scientists of the Arctic community; and that the rates of CO2 emissions were even higher where snow was deepened by our snow fence experiment says Dr. Welker. Now we know why “deeper snow keeps the soils from getting very very cold in winter (ie. warmer than thin snow areas), facilitating permafrost thaw, winter and summer microbial decomposition of the organic matter and that some of the winter and the summer CO2 emissions are ancient C (thousands of years old and previously frozen), These findings depict the importance of long-term studies and the value of using radiocarbon (14C-techniqes) to delineate the sources and ages of CO2 emissions across the changing Arctic”
The team’s findings, Czimczik explained, suggest that even if humanity stopped emitting planet-warming gases like carbon dioxide immediately, ancient C emissions from Arctic sources would still continue. “The implications are that if the climate models are right and the observations continue to show an increase in snow, then in addition to the strong warming, the snow will greatly accelerate emissions from permafrost,” said Czimczik”
Until now, climate change computer models that help groups like the Intergovernmental Panel on Climate Change forecast different climate change scenarios do not take emissions from permafrost into account because those emissions are hard to quantify. But, Drs. Pedron, Jespersen, Welker and Czimczik built sensors (deep soil wells and passive CO2 traps) at the University of Alaska Anchorage and at UC Irvine and installed the new technology allowing them to measure and capture the carbon emissions at their field site in Arctic Alaska. “We can even see the ancient carbon emissions during the summer,” which is when snow depths ought to be at their lowest levels” said Drs. Pedron and Jespersen.
Current climate change is causing snow and ice to retreat across much of the Arctic. But the same warming driving the retreat is also driving increased evaporation and, therefore, precipitation in certain regions. The deeper the snow gets, the more heat the snow traps in the soil each autumn when a blanket of snow covers the landscape. This causes the upper layers of the permafrost to thaw, which allows microorganisms to consume the thawed organic matter and, in the process, release planet-warming gases.
“Permafrost emissions are going to start earlier than we expected in most of our models,” said Czimczik. “We have an opportunity to control the emissions that are under our human control, otherwise these are going to further derail us from our climate mitigation targets.”
Czimczik added that she hopes a growing awareness of the threat of emissions from sources that humans have little control over helps to further encourage nations to curb emissions. “It’s an opportunity for individuals, but also CEOs and governments, to incentivize regulating emissions, and we need to start now and do an even better job, otherwise we’ll miss that target.”
Deeper snow mobilizes ancient permafrost carbon: An ITEX Study
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