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As observed by the United Nations Environment Program (GRID-Arendal) ice and snow are major components of the climate system. That is why human induced climate change can be first observed in Polar Regions where most of Earth's snow and ice are concentrated. In these areas global warming induces the progressive melting of ice and snow. As a consequence more solar radiation is absorbed and lesser radiation is reflected back from the Earth's surface, creating an increased warming which again accelerates the process of melting of ice.
Arctic sea ice extent has shrunk by 2.7% per decade since 1978. Antarctic sea ice is expected to decline as well but won't thin as much. In Greenland, the largest-outlet glacier which represents 6.5% of the ice sheet is melting at an accelerated rate: in the last decade the sheet loss rate has reached 200 cubic km/year (against 90 cubic km/year in the early 90s).
The shrinking of snow cover can also be observed in other parts of the globe. It is particularly acute in spring and summer as an earlier spring season induces earlier and longer melting of glaciers in mountain areas.
Rising temperature is leading to a dramatic shrinkage of glaciers that could end with their total disappearance in many mountains in the next decades (Himalayas, Andes, Rocky Mountains, and Alps). Mid-latitudes are expected to experience a major decrease of snow cover along with snow lines rise.
It is estimated that this global ice and snow melting has been responsible for a sea level rise of 0.77 mm/year between 1993 and 2003.
Also, it is expected that permafrost (ice land) contains a large quantity of carbon which, in case of thawing, will be released in the atmosphere and will contribute to the acceleration of global warming. This process, which has not yet started, could be observed at the end of the 21st century, mostly in Northern America.
According to a study led by the United Nations Environment Program and the International Center for Integrated Mountain Development (Kathmandu, Nepal) the threat that lakes' overflow poses to the life of millions of people is growing. In the next decade, the Himalayas are projected to suffer from devastating Glacial Lake Outburst Floods (GLOFs) and landslides. GLOFs result from the failure of moraine dams when excessive hydrostatic pressure is exerted on dam walls as a result of increased melting and increased water depth in lakes.
GLOFs could result in the massive destruction of costly mountain infrastructures (roads, bridges and hydropower plants), human settlements, fields and forests. This would lead to an aggravation of poverty in already disadvantaged regions.
The size of many lakes of the Himalayas is expanding. In Nepal, for example, Tsho Rolpa lake's imminent risk of flooding pose a threat to a village located 108 km downstream: 10.000 human lives, livestock, land, bridges and other infrastructures are at stake. In Northern Bhutan (Lunana area) a catastrophic glacial lake outburst led in 1994 to the death of 21 persons, damaged villages and washed away bridges.
In the longer term, with the progressive disappearance of glaciers in the regions where water resources rely on snowmelt (Latin and North America, Asia, Europe), access to water will become a drastic problem. This will not affect only mountainous population but also floodplain and lowlands populations as glaciers' water feed important rivers. As Achim Steiner, United Nations Environment Program's Executive Director, stated: "Millions if not billions of people depend directly or indirectly on these natural water storage facilities for drinking water, agriculture, industry and power generation during key parts of the year".
According to the Geological Survey of India, glaciers in India are receding at a rate of 15 meters per year, mainly because of rising temperatures. Perennial rivers could turn into seasonal rivers leading to water scarcity in the summer months when Himalayan melt water represents 75% of the river water. Massive implications are expected such as lack of freshwater for major agricultural regions; power scarcity as hydropower plants depend on Himalayan water runoff; water shortage for daily consumption. In the case of Ganga river, the loss of glacier melt water would reduce July-September flows by two thirds and affect 500 million people and 37% of India's irrigated land.
At the present pace, many of the Himalayan glaciers spreading over 33.000 km2 could eventually disappear in the next decades. It is estimated that half a billion people in the Himalaya-Hindu-Kush region and a quarter billion downstream could be seriously affected as the main rivers that originate in the Himalayas (mainly Ganga, Indus and Brahmaputra) and that criss-cross the northern Indian plain could become seasonal rivers. Such expected development would induce dramatic changes in economic patterns of the affected regions, especially for irrigated agriculture.
Glacier retreat and a lesser snow cover will also have other kinds of economic impacts, for example on the local tourism industry. Ski slopes will have to be moved higher and artificial snow will have to be used, which means important financial and logistical investments.
Apart from a global policy aiming at reducing the human causes of global warming (reduction of greenhouse gas emissions), one way of mitigating the impact of melting glaciers and related floods is to develop warning systems to alert people. It is also to invest in engineering works so as to reduce water levels in lakes. But such works are very expensive for the developing countries. Funding of anti-disaster projects has thus become a vital challenge.
Ice and snow melting are projected to deeply affect ecosystems and bio-diversity as many plant and animal species, deprived from their natural environment, won't be able to survive such climate change. In the Polar region alone many species will be seriously affected by ice melting and warming of oceans temperature: bacteria, algae, crustaceans, migratory birds, penguins, seals, polar bears, whales. The same process will affect mountainous ecosystems of the Alps, Himalayas or Andes.
Moreover the changes in their natural environment will force indigenous populations, especially in the Northern Hemisphere (e.g. Inuit), to abandon their traditional way of living, hunting, fishing, travelling, and transporting. All these ancient cultures are likely to disappear.
The only 'positive' effect of ice retreat in the Arctic concerns the new possibility of exploiting its oil and gas reserves. As in the next decades a shortage is expected in these two energy sources, (essential to our economic development models), such a perspective could represent a temporary relief but, at what cost?
Indian Industry Launches National GHG Inventory Program by Neelam Singh, 30th May 2008 - Click here
Over 40 Indian companies have launched the India GHG Inventory Program. The program is the latest national-level program for corporations to measure and manage their GHG emissions based on internationally recognized standards
These modules are designed for anyone interested in the subject of polar meteorology. This section explores the role of polar regions in global climate changes using a simple global climate model NS why polar regions play such an important role in climate change and how various physical properties affect climate change.
The World Glacier Monitoring Service (WGMS), a centre based at the University of Zurich in Switzerland and that is supported by UNEP calculates thickening and thinning of glaciers in terms of 'water equivalent'.
The WGMS findings contain figures from around 100 glaciers, of which 30 form the core assessment, found in Antarctica, Asia, Europe, North America, Latin America and the Pacific. The current trends in glacial melt suggest that the Ganga, Indus, Brahmaputra and other rivers that criss-cross the northern Indian plain may become seasonal rivers in the near future as a consequence of climate change with important ramifications for poverty and the economies in the region
Scientists from US National Snow and Ice Data Center (NSIDC) say that much of the ice is so thin that it melts easily, and the Arctic may be ice-free in summer within five to 10 years.