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                                                                   Global Warming

                            History of Global Climate Change and How it Can Affect US

     Approximately 10,000 years ago , the Earth emerged from the last ice age (the Pleistocene), as the climate began to warm up. Only recently have scientists discovered the speed of this ancient "global warming" event. Evidence from the Greenland ice sheet suggests that as the temperatures rose by 7 degrees Celsius in just 50 years .This is even more rapid than the global warming predictions for the next century (+ two degrees Celsius by 2100 ,according to the Intergovernmental Panel on Climate Change). Some species take centuries or evenmillennia to respond to climate change. Using GCMs , it has been suggested that to keep pace with future global warming , trees in Europe would have to migrate at least 5 to 6 km per year .

      Evidence suggests that most species would be unable to maintain this rate and would only catch up if the warming eventually stabliized. In some ecoysystems, changes are already underway. The coniferous boreal forest of Canada, Alaska, Siberia and Scandinavia are a good example. Only eight species of trees

are found within these forests , and these are mainly conifers that have adapted to the prevailing cold climate . Higher temperatures since 1976 have sparked larger and more frequent fires through the forests , and they have also suffered storm and insect damage . All of this stress is being placed on an ecosystem already weakened by logging and burning .

     Global warming is expected to be greatest at high latitudes . If the polar ice caps melt , this could alter the course of the Gulf Stream . Britain would then become cooler and its climate would be similar to that of Spitsbergen in Norway . Instead of a southern European landscape of sunflowers and vineyards , we would see a landscape of stunted birch trees , mosses , lichens , snow buntings and musk - oxen . Such uncertainty makes it more difficult to justify long - term conservation policies .

      The threat of widespread habitat fragmentation in a warmer world is another reason why it is vital to reduce greenhouse gas emissions and to give the environment greater protection . Conservation of our
environment means careful location and management of nature reserves, maintenance of gene pools to sustain genetic diversity , and laws to prevent further damage to protected areas . The vegetation changes of the past occurred in the absence of human activity; we must ensure that human activity does not reduce the ability of plants and animals to adapt to future climate change.

Korchackovscaua Katerina
Age 14
School #33 ,

Tomina street,28,
Grodno , Belarus 230026.

Hi Katerina,
Thanks for your article on Global Warming. There is no doubt that global temperature has increased- approximately .5 degress Celsius according to my environmental science textbook.. Climate change has occured repeatedly throughout natural history- you mentioned the last ice age. However, now that the human population is much larger, a temperature change would have severe implications on people, caused by changes in climate which would affect agriculture and a rise in sea level . We have to decide whether to learn how to live with those changes or reduce emissions of greehouse gasses such as carbon dioxide through energy conservation and the use of alternative energy

Ariela Zamcheck
Stuyvesant HS
NYC, USA