중앙데일리

[FOUNTAIN] Feeling Warm? Time for Change

Apr 03,2001
The sun today is about 40 percent brighter than it was 4.6 billion years ago when the earth was formed, and yet, the average temperature of the earth has been steady enough to allow organisms to exist continually ever since the first forms of life appeared 3.5 billion years ago. Scientists can explain how the earth has maintained a fairly constant average temperature. Though the sun is brighter today than it was billions of years ago, the atmosphere in the early years of the life of the earth contained more carbon dioxide than today, increasing the temperature via the greenhouse effect. As time went by and the sun became hotter, more green plants grew wild, reducing carbon dioxide through photosynthesis.

Today, the ratio of carbon dioxide in the atmosphere is 300 parts per million, or 0.03 percent. However, if reckless deforestation and extravagant use of fossil fuels continue, the density of carbon dioxide in our atmosphere will almost double by 2100, reaching 550 ppm. That will push temperatures up 1.3 to 4 degrees centigrade, and sea levels will rise 15 to 95 centimeters, according to a report by the Intergovernmental Panel on Climate Change. This has sparked concerns not only of climate change, but that many coastal areas - home to half the world's population - will be submerged. To prevent such a disaster, developed countries adopted the Kyoto Protocol at the United Nations Framework Convention on Climate Change in 1997. They agreed to control emissions of gases responsible for the greenhouse effect. Now, the Bush administration has announced that the United States will not observe the Kyoto Protocol signed by former President Bill Clinton. It argues that following the protocol would have a serious impact on its economy. Yet every year the United States accounts for 48 percent of greenhouse emissions by industrialized countries, and it should take responsibility for the consequences.

Scientists proposed various alternatives to resolve the problems. Some suggest covering part of the sea's surface with white Styrofoam to reflect the sun's heat. Others propose painting all building roofs white. Another idea is to block sunlight by making a gigantic artificial satellite umbrella. In order to cancel out the greenhouse effect when the amount of carbon dioxide in our atmosphere doubles, the umbrella would have to cover at least 2 percent of the earth's surface. Wallace Broecker, a geochemist at Columbia University, proposed pumping sulfur dioxide into the stratosphere to block the sun's heat. Although this would also cause acid rain, it could be an extreme way to stop global warming. Scientists warn that our lifestyle may lead to the end of a climate suitable for living. Unless we implement urgent measures, we are stealing the future from the next generation.




by Cho Hyun-wook




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