The Arctic is warming faster than the rest of the globe and is experiencing some of the most severe climate impacts on Earth. One of the most notable is the rapid decline in the thickness and extent of sea ice.
Some models suggest the Arctic Ocean could be ice-free in summer by 2030 whilst others suggest it could be as early as 2012. Permafrost is thawing, glaciers are melting, and the massive Greenland Ice Sheet is losing ice at record rates.
Sea ice underpins the entire Arctic marine ecosystem, and as it shrinks and thins, there are major repercussions for the Arctic peoples and wildlife.
The increasingly rapid rate of climate change poses new challenges to the resilience of Arctic life.
In addition to the impacts of climate change, many other stresses brought about by human activities are simultaneously affecting life in the Arctic, including air and water contamination, over-fishing, increasing levels of ultraviolet radiation due to ozone depletion, habitat alteration and pollution due to resource extraction.
The sum of these factors threatens to overwhelm the adaptive capacity of some Arctic populations and ecosystems.
"I have seen firsthand the impacts of global warming in the Arctic, when the sea ice retreated so far offshore that a lone polar bear was stranded in open water, swimming for what little ice it could find in search of its ringed seal prey that were hundreds of miles away at the ice edge. That bear was not long for this world, and the image haunts me every time I read another grim report about the plight of polar bears in our warming world." -Melanie Duchin, Greenpeace Climate Campaigner
Effect on Arctic peoples' lives and wildlife
Many indigenous peoples are and will be negatively impacted as reduced sea ice causes the animals on which they depend for food to become less accessible and to decline in numbers. Some species are already facing extinction. Coastal erosion caused by rising sea level and a reduction in sea ice are allowing higher waves and storm surges to reach the shore, so that some coastal communities are already being forced to relocate.
Polar bears are completely dependent on sea ice for their entire lifecycle - from hunting seals, their main prey, to raising their cubs. Researchers are reporting an increasing number of polar bears drowning because they have to swim longer distances between ice floes. Others are spending more time on land fasting as they wait for the sea ice to freeze up at the end of summer. Research has also found that for the first time, polar bears are cannibalizing each other due to food related stress, a direct impact of the loss of sea ice caused by climate change.
Many other species such as seals, whales and walrus also depend on the sea ice. Ice-dependent seals, including the ringed seal, ribbon seal, spotted seal and bearded seal, are particularly vulnerable to the observed and projected reductions in Arctic sea ice because they give birth to and nurse their pups on the ice and use it as a resting platform. They also forage near the ice edge and under the ice. It is very unlikely these species could adapt to life on land in the absence of summer sea ice.
Sea Ice Yearly Minimum 1979 - 2007
Effects on the global climate
The Arctic has been called "the world's refrigerator," and one reason is the role of sea ice in regulating global climate. Sea ice reflects light, whereas the dark Arctic Ocean absorbs light. As sea ice melts, more of the Arctic Ocean is exposed, meaning more sunlight is absorbed. This causes more warming, which in turn causes more sea ice to melt and continues the process. This is an example of a feedback loop, a situation where warming causes yet more warming to occur.
Another feedback loop in the Arctic is melting permafrost. Permafrost is ground that is literally frozen solid, and it can be found throughout the Arctic land environment as well as the seabed below shallow parts of the Arctic Ocean. As temperatures rise, permafrost melts, releasing trapped methane into the atmosphere. Methane is a powerful greenhouse gas, so as the permafrost melts and releases methane into the atmosphere, warming is exacerbated which in turn causes more permafrost to melt.
As sea ice loss and melting permafrost create further global warming, the Arctic meltdown has grave consequences for the entire planet.