Effect on Methane Emissions
Apart from carbon dioxide, methane (CH4) emissions also seem to be affected by the decline in sea ice. The Arctic region is an important source of this gas, with a slow but constant release of CH4 into the atmosphere. The warmer temperatures caused by the reduced extent of sea ice, however, may enhance this release.
This phenomenon may cause long-term problems, because CH4 is also a greenhouse gas, with a global warming potential (GWP) about 25 times higher than CO2. This could lead to a vicious circle, increasing the air temperature even more, and causing even higher CH4 release.
According to Dr. Parmentier:
“We have less data available for methane emissions; it is, therefore, more difficult to establish a connection between sea-ice extent and CH4 release. However, it is reasonable to think that, with a smaller sea-ice extent, an increase in CH4 emissions is likely; indeed some modelling studies predict this.”
Decrease in Sea Ice and Greenhouse Gas Fluctuation: Widespread Consequences?
The decrease in the extent of sea ice and subsequent effect on greenhouse gas fluctuations can have an impact on several aspects of the Arctic region, beyond the marine environment. The terrestrial tundra, for example, can also be affected; researchers think that the decline in sea ice has already altered the gas exchange occurring in wetland tundra, and may also influence the occurrence of tundra fires.
“Other changes may be already happening, but we know very little or nothing about them,” Dr. Parmentier said.
“The shrinkage of sea-ice extent gets more enhanced every year. Therefore, it is always more important to understand what the possible consequences of this decline will be. More detailed investigations should be performed to try to correlate the sea-ice level to the alteration of greenhouse fluxes, and, consequently, on the climate, temperature and vegetation, in the long term.”
Stroeve, J. et al. Arctic sea ice decline: Faster than forecast. (2007). Geophysical Research Letters, DOI: 10.1029/2007GL029703 Accessed February 20, 2013
National Snow and Ice Data Center. Arctic sea ice extent settles at record seasonal minimum. (2012). Accessed February 20, 2013.
Environmental Protection Agency. Methane emissions. (2012). Accessed February 20, 2013.
Parmentier, F.J.W. et al. The impact of lower sea-ice extent on Arctic greenhouse-gas exchange. (2013). Nature Climate Change, DOI: 10.1038/nclimate/1784 Accessed February 20, 2013.
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