February 25, 2002

The Heat is On for Change
In a long-awaited policy announcement, President Bush has unveiled his administration's plan to reduce global warming. Focusing on tax credits and other incentives intended to encourage but not force the cooperation of industries and business, Bush's plan aims to reduce greenhouse gas emissions in the United States — the world's largest producer of the greenhouse gases that cause global warming — approximately 4.5 percent by the year 2012.

Critics, both at home and abroad, were quick to criticize the voluntary nature of the President's proposals. Unlike the larger cuts in greenhouse gases mandated by the Kyoto treaty, the smaller cuts Bush recommends are voluntary goals; U.S. businesses will be allowed to decide for themselves whether or not to participate. (President Bush pulled the United States out of the Kyoto treaty last year over his concerns that, under the Kyoto treaty, the United States might pay too high of an economic price for cleaning up its air.) Senator Joseph Lieberman of Connecticut pointed out that the United States has already fallen short of the voluntary emission reductions it agreed to in the 1992 Rio treaty. "We've found that these voluntary programs just don't work."

Exactly what is the concern over global warming? Early last year, the United Nation's Intergovernmental Panel on Climate Change (IPCC) released four reports as part of its Climate Change 2001 project. The reports, written and reviewed by scientists from over 120 countries, were prepared to provide clear data and recommendations to policymakers around the world. In the first IPCC report, the scientists issued a clear warning: Curtail air pollution now or expect drastic climate change in the next century. That report presented the following facts:

  1. Earth's average surface temperature rose 0.6°C (1.1°F) over the last century. The authors' worst-case scenario predicts that the temperature may rise by as much as 5.8°C (11°F) during this century.

  2. A 60-70% reduction in greenhouse gas emissions (including human-caused emissions of carbon dioxide, methane, nitrous oxide, and chlorofluorocarbons) is required to stabilize the level of these pollutants in the air. Since 1750, the concentration of carbon dioxide in Earth's atmosphere has increased by 31% percent. Scientists do not believe that this level has been reached any time during the past 20 million years.

  3. Snow cover has decreased 10% over the past half-century. Glaciers have begun melting and sea levels are rising.

The IPCC scientists blame human activity for most of the current global warming. Industry and automobiles spew tremendous quantities of greenhouse gases into the air every day. The Kyoto agreements were an attempt to come up with an international plan to curb these emissions.

The risks of inaction are too great to ignore. The IPCC reports describe some possible scenarios resulting from the rise in global temperature:

  • Weather events like El Niño will become more extreme, leading to more droughts and flooding.

  • Changing ocean temperatures will lead to loss of marine species, which will cause a "catastrophic cascade in the food chain."

  • Land-dwelling animals will also be endangered because they may not be able to adapt quickly enough to the climate changes.

  • Coastal areas and small islands may become submerged, displacing large populations.

Slower Earth, Longer Days?
Scientists at the Belgian Royal Observatory announced earlier this month that they believe a steady increase in carbon dioxide in Earth's atmosphere will slow down Earth's speed of rotation. A slower rotation means longer days. But don't go buying extra suntan lotion just yet. A one percent increase in carbon dioxide each year would only add 11 extra microseconds each day every ten years.

More Links
Students can read more about the IPCC's first report in the National Geographic.com's article, "U.N. Scientists Warn of Catastrophic Climate Changes." Full text of all four IPCC reports is available at the IPCC site.

For two sides of the Bush global warming plan, students can read the following two articles from CNN.com: "Whitman details Bush emissions policy," an interview with EPA Administrator Christie Todd Whitman; and "Cool response to global warming plan," describing reaction to the Bush plan from other countries.

Think About the Problem

Many of the graphs in the Recent period show rapid growth beginning in the 1950s. Discuss with students the correlation between growth in World Population, Automobile Production, and Cattle stocks. Ask them the following questions:

  1. What is the cause of the growth of these graphs?

  2. If you were to graph the number of television sets worldwide since 1950, what do you think the graph would look like? If you compared this graph with the world temperature graph, what conclusion could you draw from this about how televisions contribute to global warming? Would this be a valid conclusion?

  3. How do scientists make the connection between greenhouse gas emissions and global warming? What roles do automobiles and industry play?

  4. Look at the Forest Land Use data graph in the Recent date range. Why does the graph drop so abruptly in the 1990s? Why does the graph represent a positive step for global warming? (Students may not be able to answer these questions without additional research. They can use the Web sites provided below in Extending the Problem to find the necessary information.)

Health Threats
Global warming carries with it increasingly dire health threats. Heat waves can increase in number and strength. Smog can increase, affecting those with respiratory problems. Changes in weather patterns can increase the frequency and severity of both floods and droughts. Finally, prolonged hotter weather can lead to booming mosquito populations — and with mosquitoes come diseases.

For an excellent discussion of the health threats due to global warming, read this Scientific American article by Dr. Paul Epstein, associate director of the Center for Health and the Global Environment at Harvard Medical School and a contributor to the Global Warming Lab.

Extending the Problem
There are extensive resources on global warming available on the Web. The following sites are appropriate for middle school and high school students:

  • The Environmental Protection Agency (EPA) site, Global Warming, provides lots of useful information about global warming, including a Visitor Center where students can read about the impact of global warming on different groups, such as small business, industry, health professionals, and outdoor enthusiasts. The Global Warming Kids Site is for younger students and includes games as well as age-appropriate information.

  • The Union of Concerned Scientists provides a curriculum guide for grades 9-12 to use with the Global Warming: Early Warning Signs map. The map is viewable online and provides exhaustive information on the "fingerprints" left behind by global climate change.

  • Global Warming: Focus on the Future is an online version of a traveling exhibit developed by the American Museum of Natural History and the Environmental Defense Fund and is meant to be a visual introduction to global warming. The exhibit puts global warming into the context of a timeline showing Earth's climate and geological development.

  • Yahoo News offers full and up-to-date coverage of Global Warming. This listing provides links to recent news articles on the latest developments related to global warming.

  • A Primer on Climate Change is Environment Canada's introduction to climate change. This site emphasizes the science of climate change and what an individual can do to reduce his or her own personal impact on the climate. Also available in French.

The following Riverdeep Current articles offer additional angles and teaching ideas related to global warming:

  • "The Heat Is On"  This multimedia article looks at how scientists study climate changes and features interviews with scientists who helped create the Global Warming Lab.

  • "Cutting Through the Smog"  NASA satellites have shown a clear, real-time picture of how air pollution quickly spreads from one country to another and affects the global atmosphere. The article examines air pollution, smog, and the impact of bad air on breathing.

  • "Cool Off with Algae"  Scientists propose that fertilizing the ocean with iron may cause more phytoplankton to grow. The phytoplankton would then absorb atmospheric carbon dioxide during photosynthesis, thereby counteracting global warming.

  • "Warming the Food Web"  Global warming disrupts animal hibernation and migration patterns.

  • "Reefs in Danger"  Earth's important, yet vulnerable reefs are threatened by global warming and pollution.