Large ice formations, like glaciers and the polar ice caps, naturally melt back a bit each summer. But, in the winter, snows, made primarily from evaporated seawater, are generally sufficient to balance out the melting. Recently, though, persistently higher temperatures caused by global warming have led to greaterthan- average summer melting as well as diminished snowfall due to later winters and earlier springs. This imbalance results in a significant net gain in runoff versus evaporation for the ocean, causing sea levels to rise. Satellite measurements tell us that over the past century, the Global Mean Sea Level (GMSL) has risen by 4 to 8 inches (10 to 20 centimeters). However, the annual rate of rise over the past 20 years has been 0.13 inches (3.2 millimeters) a year, roughly twice the average speed of the preceding 80 years.
As with glaciers and the ice caps, increased heat is causing the massive ice sheets, that cover Greenland and Antarctica to melt at an accelerated pace. Scientists also believe ice-melt water from above and seawater from below is seeping beneath Greenland's and West Antarctica's ice sheets, effectively lubricating ice streams and causing them to move more quickly into the sea. Moreover, higher sea temperatures are causing the massive ice shelves that extend out from Antarctica to melt from below, weaken, and break off. When sea levels rise rapidly, as they have been doing, even a small increase can have devastating effect on coastal habitats. As seawater reaches farther inland, it can cause destructive erosion, flooding of wetlands, contamination of aquifers and agricultural soils, and lost habitat for fish, birds, and plants. When large storms hit land, higher sea levels mean bigger, more powerful storm surges that can strip away everything in their path.
In addition, hundreds of millions of people live in areas that will become increasingly vulnerable to flooding. Higher sea levels would force them to abandon their homes and relocate. Low-lying islands could be submerged completely. Thus, it needs launching of serious awareness programme through print media, electronic media to curb the glacier melting by reducing heavy consumption of hydrocarbon and focus on zero pollution researches to develop energy production alternatives.
The Current State and 125 Kyr History of Permafrost in the Kara Sea Shelf: Modeling Constraints
