Polar regions
The polar regions are experiencing the most dramatic increase in average temperatures and the Arctic is already experiencing severe and devastating climatic changes. In 2007, summer sea ice coverage fell to a level less than 50% of that seen when records began. The loss of Arctic sea ice will not only have a dramatic impact on polar bears and local people but as the IPCC stated in 2007:
Quote
“The impacts of climate change in the polar regions over the next 100 years will exceed the impacts forecast for other regions, and will produce feedbacks that will have globally significant consequences.”
Changes in the Arctic affect the rest of the world through:
- increased warming across the globe
- rising sea levels
- alteration of oceanic processes and circulation
- potential release of huge volumes of methane, a very potent greenhouse gas.
Climate change is having a greater and faster impact on the Arctic than previously thought - air temperatures in the region have on average increased by about 5°C over the last 100 years. Change is occurring in all arctic systems, impacting on the atmosphere and oceans, sea ice and ice sheets, snow and permafrost, as well as species and populations, food webs, ecosystems and human societies.
Melting of Arctic sea ice and the Greenland ice sheet has been found to be severely accelerated. Sea ice has a higher albedo (i.e. ice and snow reflect more solar radiation than unfrozen surfaces) than ocean water; so as the ice melts, the Arctic ocean absorbs more of the sun's energy and warms up more, and that in turn warms the atmosphere more - including the atmosphere over the Greenland ice sheet. The Greenland ice sheet is, after Antarctica, the second biggest expanse of ice in the world. Greenland is already losing ice to the oceans, contributing to the gradual rise in sea levels. The ice cap holds enough water to lift sea levels globally by about 7 metres if it all melted.
Ocean circulation
Possibly the most powerful link is via the thermohaline circulation, the global conveyor taking warm water along ocean surfaces and returning colder water at depth.
Acceleration of the carbon cycle
Temperatures at the top of the permafrost layer have increased by up to 3°C since the 1980s in the Arctic. As permafrost melts more rapidly, a lot of methane will be released to the atmosphere; and this greenhouse gas is up to 20 times more potent than CO2. So melting here would create a huge positive feedback, stirring the atmospheric mix to generate further warming.
Methane also sits in the oceans and coasts sediments in enormous quantities; harming coasts and shelf seas. Sea level rise makes these methane stores vulnerable to melting and release to the atmosphere.
The only chance the Arctic has for long-term conservation is to slow then stop climate change.