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Three reasons to care about the Arctic

  • 19 Apr 2011, 15:00
  • Verity

" Climate change is melting Arctic coastlines by 30 metres each year, scientists claim" reports the Mail. " Arctic coastlines recede by 'several metres' a year" the Independent confirms.

So what's the story behind the headlines?

A new report, The State of the Arctic Coast 2010 has been released and it is based on a major undertaking. More than 30 scientists from 10 countries studied around a quarter of the entire Arctic coastline, 100,000 km in all.  They assessed the physical, ecological and social impacts of environmental change.

The report emphasises the importance of the Arctic coast, calling it

"…a locus of human activity, a rich band of biodiversity, critical habitat, and high productivity, and among the most dynamic components of the circumpolar landscape."

The Arctic coast supports the majority of indigenous communities in the area as well as very large populations of fish, mammals and birds, providing habitat for 500 million seabirds alone.

The amount of Arctic sea ice has been declining at around 13% per decade since satellite records began in 1979. The last decade has seen the warmest temperatures on record over Greenland and Canadian Arctic, whilst the summer sea ice cover has continued to decline - reaching successive record lows in 2002 and 2007. This, and the fact that the remaining sea ice is becoming thinner, means that seasonally ice-free Arctic seas have become a more imminent prospect. This puts the coast at risk.

Key findings in the report include:

Arctic coastlines more vulnerable than those at lower latitudes

Loss of sea ice means that there is a greater expanse of open water in the Arctic Ocean, in which strong waves can form. The resulting larger waves, combined with warmer, stormier seas leads to faster coastal erosion.

The research sites a report showing that on average Arctic coastlines are losing around half a metre to erosion per year - and, as the Daily Mail reported, the coast is retreating at a rate of 10-30 metres a year at the very highest level. The highest mean erosion rates are in the Beaufort, the East Siberian, and the Laptev seas.

Rocky coastlines can withstand the increase in waves and storms reasonably well. However, three quarters of the coastline that meets the Arctic Ocean consists of permafrost (frozen sediments). The high ice content of permafrost makes it especially susceptible to erosion, particularly as temperatures in the Arctic increase.

Gas hydrates could cause release of methane

Gas hydrate deposits are crystals made of ice and methane that form under high pressures and low temperatures, such as when permafrost gets buried. Small increases in temperature or a release in pressure can cause the gas hydrates to become unstable and decompose, releasing methane (a potent greenhouse gas) into the atmosphere. There is a possibility that the rising Arctic temperatures and coastal erosion could destabilise the gas hydrate deposits found there. This would act as a positive feedback, causing more Arctic warming.

Impacts on Arctic coastal communities

The accelerated coastal erosion damages the infrastructure of coastal communities - so much so that some communities are having to consider relocation. Storm surges arising in warm, open waters also have a big impact on low-lying coastal areas, adversely affecting coastal communities and ecosystems. For example, surges can break up ice roads (vital transportation links in winter) and contaminate freshwater systems with salty water. In addition, many of the subsistence communities rely heavily on having healthy coastal ecosystems. As noted by one of the authors:

"Hunting, fishing and gathering is important for large parts of the Arctic population both for food (and thus economic reasons), nutrition, cultural identity and social relationships."

This dependence is increasing threatened by the changing climate.

This is a powerful report, well worth reading in more detail, and full of interesting nuggets of information. It also adds to the ever-increasing wealth of information about why we should care about what is happening to the Arctic.

 


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