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Current Event: Global warming |
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Lead Article:Global Warming |
Support Article #1: Llanos, Miguel. A consensus emerges around global
warming. |
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Support Article #2: The International Nuclear Forum:
Kyoto Protocol |
Support Article #3: Global Warming. Encyclopedia Encarta,
11/27/01. |
Current Event:
This article is on global warming and how it is affecting the earth. This article will explain what scientists claim to be global warming. It will explain the causes and effects of global warming. You will learn how it started and how this will affect us in the future. The article also gives the opinion of skeptical scientists. This article was chosen because there is a dramatic change to our environment, and we need to be informed of what's causing it. We need to understand what we are doing wrong and how we are handling the situation. This affects you as much as anybody else. The central issue of the article is the "Greenhouse effect," and how it is affecting the climate. The underling (secondary) issues of the article include: the affects of global warming on the environment, how it is predicted to get worse, and different ways that global warming can show up. Another issue is the skepticism of other scientists on the global warming issues, and how they could be normal trends between the Earth and the sun. All regions of the Earth are affected to global warming one way or another. The higher temperatures are causing the polar ice caps to melt and the oceans may rise and send low lying areas flooded. The Earths population is rising and the dry climate could cause major droughts. Five critical thinking questions:
Supporting Articles:
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Lead Article
The Earth's average temperature has risen I degree Fahrenheit (0.5 degrees Celsius) over the past 100 years, according to climatologists. The 1990s were the hottest decade since scientists began keeping records in the late 1800s, and the 1980s were the second hottest. Climate records show that 1998 was the planet's hottest year ever, and 1997 was the next hottest, Fluctuations in the Eartlf s temperature are natural and have occurred throughout the planet's history. But a growing number of scientists have concluded that at least some of the recent increase in Earth's temperature is due to human activity. In the 1970s, some scientists began to suggest that the accumulation of certain gases in the atmosphere was contributing to global warming by trapping heat near the Earth's surface. This process was thought to work in much the same way that windowpanes in a greenhouse trap the sun's heat, hence scientists dubbed it the "greenhouse effect." The principal culprit in producing the greenhouse effect is thought to be carbon dioxide, a gas released when fossil fuels such as oil, coal and natural gas are burned. Other gases thought to contribute to global warming include chlorofluorocarbons, methane and nitrous oxide. Chlorofluorocarbons are synthetically produced chemical compounds. Methane and nitrous oxide are naturally occurring gases whose presence in the atmosphere has increased over the last century, largely due to extensive agriculture and deforestation. The Intergovenunental Panel on Climate Change (IPCC), an advisory subcommittee of the United Nations, in 1995 issued a report stating that "the balance of evidence suggests" that human activity was at least partly responsible for global warming. The report predicted that the Earth's average temperature would rise from between 1. 8 degrees Fahrenheit and 6 degrees Fahrenheit if the amount of carbon dioxide in the atmosphere doubled. At current emission rates, that concentration level would be reached by the year 2100. Scientists say that environmental consequences could be serious if warming trends continue. Hotter temperatures could increase the frequency of dramatic weather events, such as hurricanes and tornadoes. Precipitation could increase in some regions and thereby disrupt delicate ecosystems, while other parts of the globe could experience drier weather patterns and more frequent droughts. In addition, higher global temperatures could cause the polar ice caps to melt, causing a rise in sea levels. Millions of people could be forced to relocate as low-lying areas became flooded. Although most climatologists now believe that human activity is contributing to global warming, many scientists still remain skeptical. Some suggest that the recent increase in the Earth's temperature is within the bounds of the planet's natural temperature fluctuations. Others question the computer models used to predict climatic changes. Despite the impressive power of modem computers, they say, there are still many unknown factors contributing to climate changes that computer models fail to account for. Skeptics also claim that the recent warming could be the result of non-human-related causes. Some scientists have proposed that the sun undergoes cyclical changes in brightness that may account for up to 700/o of the global warming since 1850. Finally, some skeptics challenge the very notion that the Earth is getting hotter. While they acknowledge that temperature measurements taken from the ground have indicated an increase in the Earth's temperature, measurements taken from satellites over the past 18 years have actually shown a slight temperature decrease. |
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