hope 'worming' is a typo. Global warming results in melting of ice in to water raising the sea water level. More natural calamities like tornado, hurricanes etc due to sea temperature raise. I don't think it will stop.
Effects of global warming
The predicted effects of global warming are many and various, both for the environment and for human life. These effects include sea level rise, impacts on agriculture, reductions in the ozone layer, increased intensity and frequency of extreme weather events, and the spread of disease. In some cases, the effects may already be being experienced, although it is difficult to attribute specific natural phenomena to long-term global warming. In particular, the relationship between global warming and hurricanes is still being debated. [21] [22] A draft statement by the World Meteorological Organization acknowledges the differing viewpoints on this issue [23].
The extent and likelihood of these consequences is a matter of considerable controversy. A summary of possible effects and recent understanding can be found in the report of the IPCC Working Group II [24]. Some scientists believe global warming is already causing death and disease across the world through flooding, environmental destruction, heat waves and other extreme weather events. (Reuters, February 9, 2006; archived)
Effects on ecosystems
Secondary evidence of global warming — lessened snow cover, rising sea levels, weather changes — provides examples of consequences of global warming that may influence not only human activities but also ecosystems. Increasing global temperature means that ecosystems may change; some species may be forced out of their habitats (possibly to extinction) because of changing conditions, while others may flourish.
Impact on glaciers
Global Glacial Mass-Balance in the last 40 years, reported to the WGMS and NSIDC. Note the increased negative trend beginning in the late 1980s that is driving the increased rate and number of retreating glaciers.(Dyurgerov)Global warming has led to negative glacier mass balance, causing glacier retreat around the world. Oerlemans (2005) showed a net decline in 142 of the 144 mountain glaciers with records from 1900 to 1980. Since 1980 global glacier retreat has increased significantly. Similarly, Dyurgerov and Meier (2005) averaged glacier data across large scale regions (e.g. Europe) and found that every region had a net decline from 1960 to 2002, though a few local regions (e.g. Scandinavia) have shown increases. Some glaciers that are in disequilibrium with present climate have already disappeared [25] and increasing temperatures are expected to cause continued retreat in the majority of alpine glaciers around the world. Upwards of 90% of glaciers reported to the World Glacier Monitoring Service have retreated since 1995 [26].
Of particular concern is the potential for failure of the Hindu Kush and Himalayan glacial melts. The melt of these glaciers is a large and reliable source of water for China, India, and much of Asia, and these waters form a principal dry-season water source. Increased melting would cause greater flow for several decades, after which "some areas of the most populated region on Earth are likely to 'run out of water'" (T. P. Barnett, J. C. Adam and D. P. Lettenmaier 2005) [27]
Destabilization of ocean currents
Main article: Shutdown of thermohaline circulation
There is also some speculation that global warming could, via a shutdown or slowdown of the thermohaline circulation, trigger localized cooling in the North Atlantic and lead to cooling, or lesser warming, in that region. This would affect in particular areas like Scandinavia and Britain that are warmed by the North Atlantic drift.
Environmental refugees
The termini of the glaciers in the Bhutan-Himalaya. Glacial lakes have been rapidly forming on the surface of the debris-covered glaciers in this region during the last few decades. According to USGS researchers, glaciers in the Himalaya are wasting at alarming and accelerating rates, as indicated by comparisons of satellite and historic data, and as shown by the widespread, rapid growth of lakes on the glacier surfaces. The researchers have found a strong correlation between increasing temperatures and glacier retreat.Even a relatively small rise in sea level would make some densely settled coastal plains uninhabitable and create a significant refugee problem. If the sea level were to rise in excess of 4 meters (13 ft) almost every coastal city in the world would be severely affected, with the potential for major impacts on world-wide trade and economy. Presently, the IPCC predicts sea level rise of less than 1 meter (3 ft) through 2100, but they also warn that global warming during that time may lead to irreversible changes in the Earth's glacial system and ultimately melt enough ice to raise sea level many meters over the next millennia. It is estimated that around 200 million people could be affected by sea level rise, especially in Vietnam, Bangladesh, China, India, Thailand, Philippines, Indonesia and Egypt.
An example of the ambiguous nature of environmental refugees is the emigration from the island nation of Tuvalu, which has an average elevation of approximately one meter above sea level. Tuvalu already has an ad hoc agreement with New Zealand to allow phased relocation [28] and many residents have been leaving the islands. However, it is far from clear that rising sea levels from global warming are a substantial factor - best estimates are that sea level has been rising there at approximately 1-2 millimeters per year (~1/16th in/yr), but that shorter timescale factors - ENSO, or tides - have far larger temporary effects [29] [30] [31] [32].
Spread of disease
Global warming may extend the range of vectors conveying infectious diseases such as malaria. Bluetongue disease in domesticated ruminants associated with mite bites has recently spread to the north Mediterranean region. Hantavirus infection, Crimean-Congo hemorrhagic fever, tularemia and rabies increased in wide areas of Russia during 2004–2005. This was associated with a population explosion of rodents and their predators but may be partially blamed on breakdowns in governmental vaccination and rodent control programs.[33] Similarly, despite the disappearance of malaria in most temperate regions, the indigenous mosquitoes that transmitted it were never eliminated and remain common in some areas. Thus, although temperature is important in the transmission dynamics of malaria, many other factors are influential [34].
Financial effects
Financial institutions, including the world's two largest insurance companies, Munich Re and Swiss Re, warned in a 2002 study (UNEP summary) that "the increasing frequency of severe climatic events, coupled with social trends" could cost almost US$150 billion each year in the next decade. These costs would, through increased costs related to insurance and disaster relief, burden customers, tax payers, and industry alike.
According to the Association of British Insurers, limiting carbon emissions could avoid 80% of the projected additional annual cost of tropical cyclones by the 2080s. According to Choi and Fisher (2003) each 1% increase in annual precipitation could enlarge catastrophe loss by as much as 2.8%.
The United Nations' Environmental Program recently announced that severe weather around the world has made 2005 the most costly year on record [35], although there is no way to prove that [a given hurricane] either was, or was not, affected by global warming [36]. Preliminary estimates presented by the German insurance foundation Munich Re put the economic losses at more than US$200 billion, with insured losses running at more than US$70 billion.
Biomass production
The creation of biomass by plants is influenced by the availability of water, nutrients, and carbon dioxide. Part of this biomass is used (directly or indirectly) as the energy source for nearly all other life forms, including feed-stock for domestic animals, and fruits and grains for human consumption. It also includes timber for construction purposes.
A rise in atmospheric carbon dioxide can increase the efficiency of the metabolism of most plants, potentially allowing them to create more biomass. A rising temperature can also increase the growing season in colder regions. It is sometimes argued that these effects can create a greener, richer planet, with more available biomass. However, there are many other factors involved, and it is currently unclear if plants benefiting from global warming is a realistic scenario. Plant growth can be limited by a number of factors, including soil fertility, water, temperature, and carbon dioxide concentration.
IPCC models currently predict a possible modest increase in plant productivity; however there are several negative impacts: decreases in productivity may occur at above-optimal temperatures; greater variation in temperature is likely to decrease wheat yields; in experiments, grain and forage quality declines if CO2 and higher temperature are increased; and the reductions in soil moisture in summer, which are likely to occur, would have a negative impact on productivity.[37]
Satellite data shows that the productivity of the northern hemisphere has indeed increased from 1982 to 1991 [38]. However, more recent studies [39],[40] found that from 1991 to 2002, wide-spread droughts had actually caused a decrease in summer photosynthesis in the mid and high latitudes of the northern hemisphere.
NOAA projects that by the 2050s, there will only be 54% of the volume of sea ice there was in the 1950s.[edit]
Opening up of the Northwest Passage in summer
Melting Arctic ice may open the Northwest Passage in summer in approximately ten years, which would cut 5,000 nautical miles (9,300 km) from shipping routes between Europe and Asia. This would be of particular relevance for supertankers which are too big to fit through the Panama Canal and currently have to go around the tip of South America. According to the Canadian Ice Service, the amount of ice in Canada's eastern Arctic Archipelago decreased by 15% between 1969 and 2004 [41][42]. A similar opening is possible in the Arctic north of Siberia, allowing much faster East Asian to Europe transport.
Negative impacts of the melting of ice include a potential increase in the rate of global warming, as that ice reflects more sunlight than the open water which is replacing it. There are also ecological effects of melting polar ice: for example, polar bears use sea ice to reach their prey, and swim to another ice floe when one breaks up. Ice is now becoming further separated, and dead polar bears are being found in the water, believed to have drowned.[43] More recently, observed cannibalistic behavior in polar bears has been suggested by some scientists to be the result of food shortages brought on by global warming (Amstrup et al. 2006).
2006-06-29 21:29:30
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answer #6
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answered by Govinda 4
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