A. Petrescu et al. says "Methane (CH4) emission from boreal, arctic and subarctic wetlands constitutes a potentially positive feedback to global climate warming. Many process-based models have been developed, but high uncertainties remain in estimating the amount of CH4 released from wetlands at the global scale.... [T]he average annual flux over the period 2001-2006 was estimated to be 78 Tg yr-1," which is double previous estimates.
2011 methane isotope research finds that potentially, Arctic wetlands "may respond quickly and powerfully to meteorological variations and to sustained climate warming.... Wetland CH4 emissions respond rapidly to warming, such that the warming can feed the warming [Nisbet and Ingham, 1995], as evidenced by their importance in glacial terminations [Nisbet and Chappellaz, 2009]. In particular, Arctic and boreal wetlands are likely to respond immediately to sustained heatwaves and increases in precipitation."
Approximately 3.5 million square kilometres of boreal and subarctic peatlands exist in Russia, Canada, the United States (Alaska), and Fennoscandia (Finland and the Scandinavian countries).
Wetlands make up to 60% of all Arctic ecosystems. Much of the boreal forest is wetland:
• peatlands (bogs, mires)
• shallow lakes
• rivers and deltas
• periodically flooded lands
• coastal wetlands
Globally, wetlands contain 771 billion tons of greenhouse gases, 20 percent of all the carbon on Earth and about the same amount of carbon as is now in the atmosphere. Northern wetlands contribute between 5% and 10% of global methane emissions.
In 2012 research in far north east china on a transition region of permafrost and found that a large methane emissions ocurred in the spring thaw, consistent with the feedback increase in far north atmospheric methane. Large methane emission upon spring thaw from natural wetlands in the northern permafrost region, Changchun Song.
A 2009 Arctic carbon review by McGuire found that the Arctic has been a sink for atmospheric CO2 of between 0 and 0.8 Pg C/yr in recent decades, which is between 0% and 25% of the global net land/ocean ﬂux during the 1990s. The Arctic is a substantial source of methane to the atmosphere (between 32 and 112 Tg CH4/yr), primarily because of the large area of wetlands throughout the region.`
Research by David Palmer 2010 using satellite data indicates sub-Arctic methane emissions from warming wetlands are increasing. He found that the relatively small high latitude wetland methane emissions has increased 30% in five years.
The US 2008 Abrupt Climate Change Synthesis reported "the balance of evidence suggests that anticipated changes to northern wetlands ... will very likely drive a sustained increase in CH4 emissions from the northern latitudes during the 21st century. A doubling of CH4 emissions could be realized fairly easily. Much larger increases cannot be discounted."
SubArctic wetlands are rich peat so hold a huge amount of carbon. With respect to methane, emissions are assumed to include thawing permafrost which converts to peat rich wetlands.
Sept 2015 Rising methane emissions from northern wetlands associated with sea ice decline
4 Jan 2015 Large, increasing methane emissions from northern lakes today16.5 Tg CH4 yr−1.up to 50% increase by 2100
Nov 2015 Northern lakes act as carbon dioxide chimneys in a warming world
April 2015 Model estimates ..s on pan-Arctic wetland methane emissons projected 42% increase by 2100.
30 March 2015 Diverse sources of methane in shallow (thermocast) Arctic lakes discovered- biological & thermagenic
Oct 2014 better science more methane emissions
April 2014 Wetlands responsible (including subarctic) for new (post 2007) atmospheric methane increase.
2012 C. Song Large methane emission upon spring thaw from natural wetlands in the northern permafrost region
2011 Xudong Zhu, Estimating wetland methane emissions from the northern high latitudes
More than half of global wetlands are in the Far North.
Atmospheric input of CH4 from northern latitude wetlands accounts for about 25% of the total natural CH4 sources globally (Schlesinger, 1997).
Methane emissions increase with temperature and with moisture.
The NH wetlands emit most methane over the summer months- warming.
There was a large increase in NH wetlland emissions in the high Arctic warming of 2007.
A 2014 study reveals that Arctic methane emissions do consitute a planetary emergency- warming subaractic wetlands and more wetlands created as permafrost thaws release a large amount of methane. Methane emissions from warming wetlands and new wettlands from thawing permnafrost is creating a feedback loop that is "certain to trigger additional warming," according to the lead scientist of a study investigating Arctic methane emissions. (April 2014)
The study (see Research left) examined 71 wetlands across the globe and found that melting permafrost is creating wetlands known as fens, which are 'unexpectedly 'emitting large quantities of methane., that is 84 times more potent. than CO2 over a 20 year period.
The shocking finding is that wetlands known as fens, in the northern latitudes created when permafrost thaws - can have emissions similar to wetlands in the tropics. It has always been assumed thgat hot tropical wetlands woul always emit far more methane than could ever come out of the far north.
“Our study highlights that northern wetlands without permafrost emit more methane than wetlands with permafrost,” “Even if we ceased all human emissions, permafrost would continue to thaw and release carbon into the atmosphere,” lead author Merritt Turetsky said. “Instead of reducing emissions, we currently are on track with the most dire scenario considered by the IPCC. There is no way to capture emissions from thawing permafrost as this carbon is released from soils across large regions of land in very remote spaces.”