Arctic - Climate Change

Climate Change

The Arctic is especially vulnerable to the effects of global warming, as has become apparent in the melting sea ice in recent years. Climate models predict much greater warming in the Arctic than the global average, resulting in significant international attention to the region. In particular, there are concerns that Arctic shrinkage, a consequence of melting glaciers and other ice in Greenland, could soon contribute to a substantial rise in sea levels worldwide. The climate models on which the IPCC report Nr.4 is based, give a range of predictions of Arctic sea ice loss, showing near-complete to complete loss in September anywhere from 2040 to some time well beyond 2100. About half of the analyzed models show near-complete to complete sea ice loss in September by the year 2100. More recently, the Catlin Arctic Survey concluded that summer ice loss would occur around 2029. It has been apparent though since 2007, that those models grossly underestimate sea ice loss.

A good source for the measurement of arctic sea ice can be found here:.

As can be seen in the two plot at the right, since about 1995 to 2000, all three size numbers of the arctic sea ice shield (extent, area and volume) are decreasing in an accelerated way (extent can be seen here: ). This downward movement is modulated by statistical variations, which lead to considerable media attention, when a new record has been reached.

Concerning melting records, 2012 was a productive year, thus corroborating the tendency of the past decade. This may have been furthered by a strong summer storm cyclone, a rare event in the arctic, which spread the already very thin ice and caused mixing of the cold surface waters with deeper warmer water layers. According to the University of Bremen, in September 2011 the Arctic ice cap was smaller than ever before recorded since the satellite measurements started in the 1970s. Arctic ice is declining in area and thinning. Arctic temperatures have risen more than twice as fast as the global average over the past half century. The speed of change has shocked scientists. If current trends continue, a largely ice-free Arctic in the summer is likely within 30 years – up to 40 years earlier than was anticipated by the IPCC Fourth Assessment Report.

As the volume of sea ice until recently could not be measured by remote sensing as easy as its extent, numerical models have been made to estimate the ice thickness field between known points, which then is summed up to yield ice volume. The resulting volume over time – plot reveals a much stronger loss of ice than ice extent studies suggest.

The current Arctic shrinkage is leading to fears of Arctic methane release. Release of methane stored in permafrost could cause abrupt and severe global warming, as methane is a potent greenhouse gas. On millennial time-scales, decomposition of methane hydrates in the Arctic seabed could also amplify global warming. Previous methane release events have been linked to the great dying, a mass extinction event at the boundary of the Permian and Triassic, and the Paleocene–Eocene Thermal Maximum, in which temperatures abruptly increased.

Apart from concerns regarding the detrimental effects of warming in the Arctic, some potential opportunities have gained attention as well. The melting of the ice is making the Northwest Passage, the shipping routes through the northernmost latitudes, more navigable, raising the possibility that the Arctic region will become a prime trade route. In addition, it is believed that the Arctic seabed may contain substantial oil fields which may become accessible if the ice covering them melts. These factors have led to recent international debates as to which nations can claim sovereignty or ownership over the waters of the Arctic.

The National Oceanic and Atmospheric Administration's Arctic Report Card presents annually updated, peer-reviewed information on recent observations of environmental conditions in the Arctic relative to historical records.