ARCTIC AMPLIFYING FEEDBACKS
How much carbon as potential methane is there in the Arctic?
The Arctic holds several times atmospheric carbon.
o The subarctic Boreal forest is the largest forest store of carbon, even more than the Amazon.
Boreal forest fires emit mainly CO2 but some CH4 is also emitted. In forested regions over permafrost the fire thaws surface permafrost and more methane is released.
Arctic methane sources
A 2010 review of the Arctic carbon budget by D. McGuire et al finds that the Arctic contains several times the amount of carbon in the atmosphere. Most is potentially methane. The review finds many Arctic changes that will result from global warming will increase the emission of Arctic methane.
Arctic methane amplifying feedback (in particular) from multiple
large methane sources has for many years been called the Arctic
methane bomb. It is the main source of feedbacks in the runaway climate change
scenario of planetary catastrophe.
There are many very large sources of Arctic amplifying feedback.
Still the best explanation to start with is WWF's 2009
publication Arctic Climate Feedbacks:Global Implications
IPCC AR5 Feedbacks. AR5 was rather cursory on Arctic feedbacks.
Arctic Climate Feedbacks: Global Implications WWF 2009
Executive summary: èAmplification of global warming in the Arctic will have fundamental
impacts on Northern Hemisphere weather and climate.è
(Chapter 1, Atmospheric Circulation Feedbacks)
èReduced sea ice amplifies warming. Reduced sea ice cover is already amplifying warming in the Arctic earlier than projected. This amplification will become more pronounced as more ice cover is lost over the coming decades.
Amplified warming spreads over land. Amplified atmospheric warming in the Arctic will likely spread over high-latitude land areas, hastening degradation of permafrost, leading to increased release of greenhouse gases presently locked in frozen soils, leading to further arctic and global warming.
Weather patterns are altered. The additional warming in the Arctic will affect weather patterns in the Arctic and beyond by altering the temperature gradient in the atmosphere and atmospheric circulation patterns. It may also affect temperature and precipitation patterns in Europe and North America. These changes will affect agriculture, forestry and water supplies.è
A most signifant study is the 2013 paper The impact of
There are two kinds of Arctic feedback loops
ALBEDO Melting snow and ice albedo cooling loss
leads to regional warming
GHGs The warming Arctic emits the three main GHGs-
CO2 methane and nitrous oxide
There are many Arctic amplifying feedbacks
o Far North snow albedo
o Arctic summer sea ice albedo
o Boreal forest (carbon)
o Sub-arctic wetlands (carbon)
o Permafrost (carbon, N2O
o Subsea floor methane hydrate (CH4 gas)
Here is an expert description of the Arctic feedbacks The feedback loop can be described in simple terms as follows: rising CH4 emissions from wetlands, thawing permafrost, and destabilizing marine hydrates increase atmospheric CH4 concentrations; this increase in CH4 concentration, amplified by the effect of CH4 on its own chemical lifetime, results in a greater radiative forcing on climate and terrestrial ecosystems.
The ecosystems, given our current understanding, respond to the warmer, more humid conditions by an increase in BVOCs, which further augments the chemical lifetime of CH4. Finally, the resulting additional radiative forcing could lead to more or faster thawing of permafrost, further destabilization of marine hydrates, and potentially even larger wetland CH4 emissions. POSSIBLE ROLE OF WETLANDS, PERMAFROST, AND METHANE HYDRATES IN THE METHANE CYCLE UNDER FUTURE CLIMATE CHANGE: A REVIEW F. O’Connor
In addition to the warming effect of current forcing and emissions, methane plays a role in climatic feedback mechanisms that can exacerbate warming and even lead to abrupt, catastrophic climate change in the future. This risk is primarily associated with the rapid release of carbon stores in the Arctic.
A major release of Arctic methane would have a devastating impact on the global climate, and evidence indicates it has played a role in past warming events in the paleoclimate record. J. Stolaroff et al Environ. Sci. Technol. July 2012.