Every summer, some of the ice in the arctic regions melts and flows into the world’s oceans. This is a natural phenomenon. However, since 2002 CE, this melting has increased at an alarming pace, with almost 502,000 square miles of sea ice lost since this period. Scientists at the National Snow and Ice Data Center (NSIDC) and the National Center for Atmospheric Research (NCAR) find through satellite and other observations that the Arctic ice cover is retreating more rapidly than estimated by any of the eighteen computer models used by the Intergovernmental Panel on Climate Change (IPCC) in preparing its 2007 assessments.
The major cause for this increased ice loss in the Arctic regions is global warming.
The sun’s enormous energy warms the Earth’s surface and the atmosphere. Since the atmosphere is transparent, it does not absorb heat and most of it transmits back to outer space. However, certain gasses in the atmosphere like carbon dioxide and methane, referred to as greenhouse gasses, trap some of this heat on its way out, creating an insulating layer and warming the earth. Without such gasses, the average surface temperature of the earth would be 0F (-18C); unsustainable for human life. However, thanks to increased presence of these gasses in the atmosphere in recent years, the temperature is rising well above the normal 15C, and this causes serious ecological and other damages, the arctic ice loss being one of such disasters.
The increased presence of carbon dioxide and other greenhouse gasses in the atmosphere and higher temperatures is partially due to natural atmospheric oscillations, but human activity also plays a significant part.
The burning of fossil fuels in power plants, internal combustion engines of automobiles, and aircrafts all release carbon dioxide into the atmosphere. Temperate rainforests absorb much of this carbon dioxide emitted into the atmosphere. However, a surge in energy consumption and increased use of automobiles, combined with accelerated deforestation that reduces the absorbing capacity of the forests leads to increased carbon dioxide in the atmosphere.
Methane is another greenhouse gas that absorbs heat 20 times more effectively than carbon dioxide does. The presence of methane has increased by 145% percent in the last century. Most of the world’s rice grows on flooded fields, where anaerobic conditions cause the organic matter in the soil to decompose, releasing methane to the atmosphere. The production of fossil fuels also releases methane into the atmosphere.
The increased presence of carbon dioxide, methane and other greenhouse gasses increases the temperature, which in turn melts more ice than usual.
The sea ice in the Arctic region absorbs 20% of the solar radiation, and reflects back 80%, thereby providing a cooling impact. This is in contrast to areas of open water that absorb 80% of the solar radiation and reflect back 20%. Since the area under sea ice is decreasing and areas of open water are increasing, this increases the temperatures and exacerbates the loss of ice by through melting. Further, when the ice melts, the excess water weight pushes down on the glacier at the same time that water seeps through cracks to the underside, accelerating the glacier’s flow to the sea. This forms a vicious circle, wherein the ice melts at a faster pace than before.
The world is struggling to keep global warming to two degrees celsius, as governments cannot agree on the steps. Even if they agree, it will be too little too late to save the Arctic ice cap and the sea will rise 6-7 metres, says a senior expert of the Intergovernmental Panel on Climate Change (IPCC).
The effects of the arctic ice loss would be felt world over. Arctic Ice cover loss can influence winds and precipitation on other continents, possibly leading to less rain in the western United States and creating more in Europe. The melting of the Greenland ice sheet alone would drown thousands of islands and most coastal cities around the world and threaten low-lying areas around the globe with beach erosion, coastal flooding, and contamination of freshwater supplies. The melting of once-permanent ice is already affecting native people, wildlife and plants. Polar bears, whales, walrus and seals are changing their feeding and migration patterns, making it harder for native people to hunt them.
REFERENCES
http://www.nasa.gov/vision/earth/environment/arcticice_decline.html http://nsidc.org/news/press/20070430_StroeveGRL.html http://news.bbc.co.uk/2/hi/science/nature/2558319.stm http://www.nrdc.org/globalwarming/qthinice.asp http://www.agu.org/pubs/crossref/2008/2008GL035028.shtml http://www.ucsusa.org/global_warming/science_and_impacts/science/global-warming-faq.html http://www.ecobridge.org
