Earth scientists are in the midst of a revolution in their understanding of how climate change occurred in the past. Researchers are discovering the geological and astronomical forces that have changed the planet's environment from hot to cold, wet to dry, and back again, over hundreds of millions of years. Dramatic climate change is nothing new for planet Earth. The climate of the past 10,…
Earth's climate is a delicate balance of energy inputs, chemical processes, and physical phenomena. Temperatures on Venus are too hot for the human body; on Mars, they are too cold. This difference in temperature is due to the varying composition of each planet's atmosphere. All three planets receive huge quantities of solar energy, but the amount radiated back into space as heat dep…
Some observers compare global warming to nuclear war in its potential to disrupt human and environmental systems. While some sources dispute the occurrence of human-induced climate change, if temperature increases of 1.5 to 4.5 degrees Celsius (35 to 40 degrees Fahrenheit) were to take place, substantial changes would occur on Earth's surface. If average temperatures rise this much by 2030,…
The science of global atmospheric change is still in its infancy. Most of our images of the world's environmental future must come from computer and mathematical models. The most highly developed tools now available to project climatic changes are complex computer models called general circulation models (GCMs). Even these models are crude, imperfect representations of the real world and of…
The Energy Information Administration of the U.S. Department of Energy (DOE) reported that CO2 accounted for 83 percent of greenhouse gas emissions in the United States in 2001. (See Figure 2.6.) Methane (CH4) was second with 9 percent of the total, followed by nitrous oxide (N2O) with 6 percent and other greenhouse gases, such as hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexa…
Other primary greenhouse gases are what the DOE calls "engineered gases." These are gases specially designed for modern industrial and commercial purposes. They include hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6). HFCs are chemicals that contain hydrogen, fluorine, and carbon. They are popular substitutes in industrial applications for chlorofluo…
Global warming was only acknowledged as an international problem at the end of the twentieth century. At the world's first ecological summit, the 1972 Stockholm Conference, climate change was not even listed among the threats to society. Climate-change science has been developing rapidly, leading observers to recognize the complexity of the issues. In order to understand the issue of climat…
In the Swiss Review of World Affairs (July 1994), Dr. Richard Lindzen, professor of meteorology at the Massachusetts Institute of Technology, observed that a solid scientific foundation is lacking from claims that global warming is imminent. He believes that Earth's climate depends on more than the CO2 content. Instead, Earth cools by atmospheric movements upward and poleward rather than on…
Many industrialized countries have committed themselves to stabilizing or reducing CO2 emissions. President George H. W. Bush's administration (1989–1993) opposed precise deadlines for CO2 limits, arguing that the extent of the problem was too uncertain to justify painful economic measures. However, in 1989 the U.S. Global Change Research Program (USGCRP) was established and later au…
In March 2004 the Gallup Organization conducted its annual poll on topics related to the environment. Participants were asked several questions about global warming and the Kyoto Protocol. As shown in Table 2.3 more than a quarter of those asked admitted they did not have a good understanding of the global warming issue. Half of those asked said they understood the issue fairly well. Another 18 pe…
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