REUTERS/Francois Lenoir (NORWAY)
Global warming was once an uncommon term used by a few scientists who were growing concerned over the effects Global of decades of pollution on long-term weather patterns. Today, the idea of global warming is well known, if not well understood. It is not unusual to hear someone complaining about a hot day or a freak storm and remark, "It's global warming."
Well, is it? In this article, we'll learn what global warming is, what causes it, what its current effects are and what the future effects could be. Although there has been a scientific consensus on global warming, some aren't sure it's something we need to worry about. We'll examine some proposed changes in the United States' national policies related to curbing global warming and the criticisms and concerns surrounding them.
Global warming is a significant increase in the Earth's climatic temperature over a relatively short period of time as a result of the activities of humans.
In specific terms, an increase of 1 or more degrees Celsius in a period of one hundred to two hundred years would be considered global warming. Over the course of a single century, an increase of even 0.4 degrees Celsius would be significant.
To understand what this means, let's start by reviewing the difference between weather and climate.
Scientists studying our climate have been able to observe and measure changes happening around us. For example, mountain glaciers are smaller now than they were 150 years ago, and in the last 100 years, the average global temperature has increased by roughly 1.4 degrees F (0.8 degrees C) [source: EPA]. Computer modeling allows scientists to predict what could happen if the climate pattern continues on its current course, projecting, for instance, that temperatures could rise an average of 2 to 11.5 degrees F (1.1 to 6.4 degrees C) by the end of the 21st century [source: EPA].
Scientists are able to measure that melt water from Greenland's ice cap directly impacts people in the United States: The flow of the Colorado River has increased sixfold [source: Scientific American]. And scientists project that as the ice shelves on Greenland and Antarctica melt, sea levels could be more than 20 feet (6 meters) higher in 2100 than they are today [source: An Inconvenient Truth]. Such levels would submerge many of Indonesia's tropical islands and flood low-lying areas such as Miami, New York City's Lower Manhattan and Bangladesh.
WHAT IS GLOBAL WARMING?
Carbon dioxide and other gases warm the surface of the planet naturally by trapping solar heat in the atmosphere. This is a good thing because it keeps our planet habitable. However, by burning fossil fuels such as coal, gas and oil and clearing forests we have dramatically increased the amount of carbon dioxide in the Earth’s atmosphere and temperatures are rising.
The vast majority of scientists agree that global warming is real, it’s already happening and that it is the result of our activities and not a natural occurrence.1 The evidence is overwhelming and undeniable.
We’re already seeing changes. Glaciers are melting, plants and animals are being forced from their habitat, and the number of severe storms and droughts is increasing.
Courtesy: REUTERS PICTURES OF THE DECADE. Climate activists Lesley Butler and Rob Bell (R) "sunbathe" on the edge of a frozen fjord in the Norwegian Arctic town of Longyearbyen April 25, 2007. The
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