IPCC, 2007: The Arctic is expected to experience the greatest rates of warming compared with other world regions. In part, this is because ice has greater reflectivity (also known as albedo) than the ocean or land. Melting of highly reflective snow and ice reveals darker land and ocean surfaces, increasing absorption of the sun's heat and further warming the planet, especially in those regions. There is evidence that climate change is already having observable impacts in the Arctic."
Arctic warming determines the fate of the whole planet from global warming.
The reason is the enormous potential positive Arctic climate feedbacks caused by Arctic (through global) warming. Arctic carbon feedbacks are methane emissions and methane is 72 times more powerful than CO2 for 20 years after emission.
For years we have watched the Arctic warming faster than the rest of the planet. This is the science of Arctic amplfication that climate change models have predicted for years. Scientists have recently been able to say this is definitely happening and that the Arctic amplification is coming on stronger than models have projected. A 2010 research paper by Screen and Simmonds convincingly explains and confirms Arctic amplification by summer sea ice extent loss, which indicates that both the rate of Arctic warming and sea ice loss will continue to increase.
The rate of global warming for 1979 - 2010 is 0.14 ± 0.1°C/decade. The rate of warming at the North Pole is 0.42 ± 0.03°C/decade since 1979. The Arctic is warming four times faster than the global average over the past 30 years (John Christy, University of Alabama in Huntsville, 2011). By now, the Arctic must be warming at least six times faster than the rest of the planet.
NASA temperature maps (to the right; click to enlarge) show the August trend and the change in Arctic temperatures over the past 30 years. James Hansen for NASA reports Jan 2012 that since the 70s, global warming seems to have been steady and in the range of about 0.15 to 0.175 degrees per decade - maximum of 0.2 degrees per decade. Warming anomaly in the Arctic was up to 4.7 degrees for average over 2011 see Figure 1, with up to 6.6 degrees in summer, see Figure 4.
Loss of Arctic albedo
Scientists say that the main factor in the accelerating rate of Arctic warming is the loss of albedo and the heat gain resulting from the accelerating Arctic sea ice loss. This section of the WWF Arctic Feedbacks report explains how loss of sea ice albedo amplifies Arctic warming. In fact, where the summer sea ice is open, the Arctic temperature increase is greatest.
Black carbon (soot) deposited on Arctic snow from Northern hemispere air pollution is a significant cause of albedo loss.
A winter thermal inversion adds to the amplification.
Water flowing into the Arctic Ocean from the Atlantic Ocean is about 2°C warmer today than it has been for at least 2,000 years, from Arctic warming amplification (so another feedback), according to a Science paper, Enhanced Modern Heat Transfer to the Arctic by Warm Atlantic Water, by R. Spielhagen et al., January 2011.
Another factor in Arctic amplification is a 2011 finding by C. Kinnard that "early 21st-century temperatures of Atlantic water entering the Arctic Ocean are unprecedented over the past 1450 years and are presumably linked to the Arctic amplification of global warming."
Some global warming emissions (methane, tropospheric ozone, black carbon) concentrate over the Arctic and may be adding to Arctic amplification (Short-lived pollutants in the Arctic: Their climate impact, P. K. Quinn et al, 2008). Atmospheric methane is concentrated over the poles, especially the Arctic (hydroxyl is not efficient at removing methane over the cold regions). The Svalbard atmospheric monitoring site has been recording a recent increase in Arctic methane concentration.
Sea surface temperature increases for the Arctic are highest over the continental shelves and that is where the vulnerable methane hydrate is located.
How will Arctic amplification affect the rate of Arctic warming, northern hemisphere warming, and global warming?
We do have one published indication of how the loss of Arctic summer sea ice will increase the rate of Arctic warming, from David Lawrence in 2008.
He found that "during episodes of rapid sea-ice loss in the past, the rate of Arctic land warming is 3.5 times greater than the average 21st century warming rates predicted in global climate models. While this warming is largest over the ocean, the simulations suggest that it can penetrate as far as 900 miles inland. The simulations also indicate that the warming acceleration during such events is especially pronounced in autumn. The decade during which a rapid sea-ice loss event occurs could see autumn temperatures warm by as much as 5 degrees C (9ºF) along the Arctic coasts of Russia, Alaska, and Canada."
This is highly significant to the increase in methane emissions from thawing permafrost and destabilizing methane hydrates.
At the 2011 AGU meeting –Dr. Jennifer presenting Francis of Rutgers University, in her talk “Does Arctic Amplification Fuel Extreme Weather in Mid-Latitudes?” said “The question is not whether sea ice loss is affecting the large-scale atmospheric circulation…it’s how can it not?"
Though there is no question that Arctic amplification will be felt by the rest of the planet, models so far are unable to forecast what Arctic amplification will do directly to northern hemisphere and global climate change. However, the increase in Arctic methane emissions is inevitable and will definitely increase the rate of warming, especially the warming that will continue to be greater in the northern hemisphere.