Global Warming

One reason the earth is teeming with life is the existence of a natural greenhouse effect. The earth is heated by the sun. After the sun's rays strike the earth, many of them bounce back into space, and the planet would be much colder if there were not gases in the atmosphere to trap part of the heat from these reflected rays. Since the start of the industrial revolution, changing economic activities have been increasing the concentrations of heat-absorbing greenhouse gases (GHGs) in the atmosphere. Computer-generated climate models suggest that the buildup of these additional GHGs, particularly carbon dioxide (CO2) from burning fossil fuels, will warm the earth's surface. The hypothesis that there will be rising global temperatures from increased human emissions of GHGs and that temperature increases will in turn melt global ice caps, raise sea levels, and increase extreme weather events like hurricanes and floods is what has come to be termed global warming.

According to the Intergovernmental Panel on Climate Change (IPCC)—a worldwide network of scientists set up in 1988 by the World Meteorological Organization and the UN Environment Program to report on all aspects of global warming—global average surface temperatures have increased about 1.0° F since the late 19th century. The 10 warmest years of the 20th century all occurred in the last 15 years of that century, with 1998 being the warmest year on record. Globally, sea levels have risen 4 to 8 inches over the past century. These observations appear to be consistent with what climate models predict: increased concentrations of greenhouse gases in the atmosphere will act like a heat-trapping blanket and raise global temperatures, the heat will cause the oceans to warm and expand, hurricanes will increase in intensity, and so on.

As a result of this apparent congruence between theoretical expectations and observations, many scientists, policymakers, and environmentalists believe that action to reduce future emissions of temperature-raising GHGs is imperative. Since 1997, more than 150 nations have ratified the Kyoto Protocol, which aims to reduce emissions of CO2. The Kyoto Protocol is a first step toward mitigating global warming, but given that it falls far short of the large and costly reductions of GHGs recommended by the IPCC, some warming is seen as inevitable. This will necessitate adaptation strategies to prevent or reduce undesired consequences. Possible adaptations include defenses against rising sea levels and hurricanes, as well as assuring food security. Overall, then, the framing of global warming as a social problem can be deemed a partial success. Its main limitations include the absence of the United States from the Kyoto process, the probable withdrawal of Canada from it, the likelihood that many countries in the European Union will not meet their reduction targets, and the challenge of incorporating China and India into the Kyoto process.