Rising Sea Levels
Perhaps the most pervasive climatic effect of global warming is rapid escalation of ice melt. Mount Kilimanjaro inAfrica, portions of the SouthAmericanAndes, and the Himalayas will very likely lose most of their glacial ice within the next two decades, affecting local water resources. Glacial ice continues its retreat inAlaskA、NASA、scientists determined that Greenland’s ice sheet is thinning by about 1 m per year. The additional meltwater, especially from continental ice masses and glaciers, is adding to a rise in sea level worldwide. Satellite remote sensing is monitoring global sea level, sea ice, and continental ice. Worldwide measurements confirm that sea level rose during the last century.
Surrounding the margins ofAntarctica, and constituting about 11% of its surface area, are numerous ice shelves, especially where sheltering inlets or bays exist.Covering many thousands of square kilometers, these ice shelves extend over the sea while still attached to continental ice. The loss of these ice shelves does not significantly raise sea level, for they already displace seawater. The concern is for the possible surge of grounded continental ice that the ice shelves hold back from the seA、
Although ice shelves constantly break up to produce icebergs, some large sections have recently broken free. In 1998 an iceberg (150 km by 35 km) broke off the Ronne Ice Shelf, southeast of theAntarctic PeninsulA、In March 2000 an iceberg taggedB-15 broke off the Ross Ice Shelf (some 90° longitude west of theAntarctic Peninsula), measuring 300 km by 40 kin. Since 1993, six ice shelves have disintegrated inAntarcticA、About 8,000 km of ice shelf are gone, changing maps, freeing up islands to circumnavigation, and creating thousands of icebergs. The Larsen Ice Shelf, along the east coast of theAntarctic Peninsula, has been retreating slowly for years. Larsen-A、suddenly disintegrated in 1995. In only 35 days in early 2002, Larsen-B、collapsed into icebergs. This ice loss is likely a result of the 2.5℃ temperature increase in the region in the last 50 years. In response to the increasing warmth, theAntarctic Peninsula is sporting new vegetation growth, previously not seen there.
A、loss of polar ice mass, augmented by melting of alpine and mountain glaciers (which experienced more than a 30 % decrease in overall ice mass during the last century) will affect sea-level rise. The IPCC、assessment states that "between one-third to one-half of the existing mountain glacier mass could disappear over the next hundred years".Also, "there is conclusive evidence for a worldwide recession of mountain glaciers... This is among the clearest and best evidence for a change in energy balance at theEarth’s surface since the end of the 19th century. "
Sea-level rise must be expressed as a range of values that are under constant reassessment.
The 2001 IPCC、forecast for global mean sea-level rise this century, given regional variations, is from 0.11～0.88 m.
The median value of 0.48 m is two to four times the rate of previous increase. These increases would continue beyond 2100 even if greenhouse gas concentrations are stabilizeD、

The Scripps Institute of Oceanography in La Jolla,California, has kept ocean temperature records since 1916. Significant temperature increases are being recorded to depths of more than 300 m as ocean temperature records are set.Even the warming of the ocean itself will contribute about 25% of sea-level rise, simply because of thermal expansion of the water. In addition, any change in ocean temperature has a profound effect on weather

Thermoregulation
Mammals and birds generally maintain body temperature within a narrow range (36-38~C、for most mammals and 39-42℃ for most birds) that is usually considerably warmer than the environment.Because heat always flows from a warm object to cooler surroundings, birds and mammals must counteract the constant heat loss. This maintenance of warm body temperature depends on several key adaptations. The most basic mechanism is the high metabolic rate of endothermy itself.Endotherms can produce large amounts of metabolic heat that replace the flow of heat to the environment, and they can vary heat production to match changing rates of heat loss. Heat production is increased by such muscle activity as moving or shivering. In some mammals, certain hormones can cause mitochondria to increase their metabolic activity and produce heat instead of ATP. This nonshivering thermogenesis (NST) takes place throughout the body, but some mammals also have a tissue called brown fat in the neck and between the shoulders that is specialized for rapid heat production. Through shivering and NST, mammals and birds in cold environments can increase their metabolic heat production by as much as 5 to 10 times above the minimal levels that occur in warm conditions.
Another major thermoregulatory adaptation that evolved in mammals and birds is insulation (hair, feathers, and fat layers), which reduces the flow of heat and lowers the energy cost of keeping warm. Most land mammals and birds react to cold by raising their fur or feathers, thereby trapping a thicker layer of air.
Humans rely more on a layer of fat just beneath the skin as insulation; goose bumps are a vestige of hair-raising left over from our furry ancestors.
Vasodilation and vasoconstriction also regulate heat exchange and may contribute to regional temperature differences within the animal.
For example, heat loss from a human is reduced when arms and legs coo] to several degrees below the temperature of the body core, where most vital organs are locateD、

Hair loses most of its insulating power when wet. Marine mammals such as whales and seals have a very thick layer of insulation fat called blubber, just under the skin. Marine mammals swim in water colder than their body core temperature, and many species spend at least part of the year in nearly freezing polar seas. The loss of heat to water occurs 50 to 100 times more rapidly than heat loss to air, and the skin temperature of a marine mammal is close to water temperature.Even so, the blubber insulation is so effective that marine mammals maintain body core temperatures of about 36-38℃ with metabolic rates about the same as those of land mammals of similar size. The flippers or tail of a whale or seal lack insulating blubber, but countercurrent heat exchangers greatly reduce heat loss in these extremities, as they do in the legs of many birds.
Through metabolic heat production, insulation, and vascular adjustments, birds and mammals are capable of astonishing feats of thermoregulation. For example, small birds called chickadees, which weigh only 20 grams, can remain active and hold body temperature nearly constant at 40℃ in environmental temperatures as low as -40℃--as long as they have enough food to supply the large amount of energy necessary for heat production.
Many mammals and birds live in places where thermoregulation requires cooling off as well as warming. For example, when a marine mammal moves into warm seas, as many whales do when they reproduce, excess metabolic heat is removed by vasodilation of numerous bl

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