The IntergoVernmental pANEL oN Climate Change Ipcc

The Intergovernmental Panel on Climate Change (IPCC) is a group of approximately 2,500 scientists working together to study the problem of global warming and focusing on a workable strategy to deal with the problem before it is too late. The IPCC was formed jointly in 1988 by the United Nations Environment Programme (UNEP) and the World Meteorological Organization (WMO) because of a growing worldwide concern over global warming. It is considered to be the most technical and authoritative group of experts on global warming in the world. The scientists who make up the IPCC are the world's top scientists in all relevant fields, such as physics, chemistry, geography, geology, medicine, economics, sociology, botany, biology, and others. Together, they write and review scientific literature on global warming issues and produce authoritative findings on the status of global warming and its effects on the Earth and its climate.

The IPCC has been studying global warming for many years and has released four reports over the past 17 years: in 1990, 1996, 2001, and 2007. In the 2007 report, Dr. Rajendra Pachauri, the chairman of IPCC, reported at an international conference in Mauritius, which representatives of 114 governments attended, that he personally believes that the world has "already reached the level of dangerous concentrations of carbon dioxide in the atmosphere" and called for immediate and "very deep cuts" in the pollution if humanity is to "survive." He also said that "climate change is for real. We have just a small window of opportunity and it is closing rather rapidly. There is not a moment to lose." He based his remarks on the following observations:

• Coral reefs throughout the world are perishing as the oceans warm up. So far, up to a quarter of the world's corals have been destroyed.

• Based on a multiyear study by 300 scientists, the Arctic is warming twice as fast as the rest of the world. The ice has melted so fast, it has shrunk 20 percent in the last 30 years alone.

• Arctic ice is also 40 percent thinner today than it was in the 1970s and is expected to be completely gone by 2070.

• The effects of global warming we are feeling today are due to the CO2 put in the atmosphere in the 1960s. When we feel the greater effects of increased pollution from later decades it will be even more severe.

The IPCC issued its fourth report in 2007, six years after its third report. Because scientists like to project their findings in terms of probabilities,

One of the largest contributors to greenhouse gases through the burning of fossil fuels is automobiles. The United States is the world's largest consumer of petroleum. (Nature's Images)

leaving an opening for the possibility of new findings, the IPCC report is also given in terms of probabilities. But an interesting thing happened in the 2007 report that had not happened before. The IPCC is made up of many scientists from many diverse fields, countries, and backgrounds. In the past the IPCC's reports have been very conservative. The 2007 report, however, has a much different tone. This report was worded much more forcefully than ever before.

This time the IPCC said the likelihood was 90 to 99 percent (labeled "very likely") that emissions of heat-trapping greenhouse gases like CO2, originating from smokestacks and automobile tailpipes, were the dominant cause of the observed warming of the past 50 years.

This is a significant change. In its first report (1990), the IPCC found evidence that global warming was real but concluded it could be caused as much by natural factors as human factors. Then, in its 1996 report, it changed its stand and supported the idea that most of the evidence suggested a definite human influence on global climate. In its third assessment (2001), it raised the human component and said that the probability of human activity being responsible for most of the warming of the 1900s was likely—the equivalent of a 66 to 90 percent probability. Finally, in its most recent report (2007), it has classified human activity as 90 to 99 percent (very likely) the major force behind global warming. When that many scientists are working together, giving an overwhelmingly high probability consensus on such a controversial issue, it stands as a strong testament to the severity of the threat of global warming. Scientists have shown that doubt and skepticism have given way to certainty. Overwhelmingly, the world's foremost authorities on global warming agree that the issue has become a risk to the Earth and humanity.

It is important to note that even though the general consensus supports the realities of global warming, scientists have not closed their minds to the issue. An integral part of scientific inquiry is that new evidence can always be revealed and either strengthen or challenge conclusions. In this regard, scientists keep an open mind that new evidence could be found to either lessen the severity of human actions on the environment or show that the situation may actually be worse than initially expected.

As noted in the New York Times by William K. Stevens on February 6, 2007, one significant factor is that the IPCC's conclusions have become significantly, consistently stronger over the past 17 years, even though the IPCC has lost some scientists and gained new ones throughout this time. As scientific inquiry uncovers increasing evidence of the human factor involved in global warming, the scientific consensus around the world increasingly supports the findings of the IPCC. The IPCC announced that global warming is a certainty and pointed out that 11 of the last 12 years were among the 12 warmest ever recorded. Adding to its growing list of evidence, the IPCC also noted the following in its 2007 report:

• Droughts in some areas of the world have increased in intensity and length, causing severe impacts on human settlements.

• Precipitation patterns have altered the tropical and subtropical regions (the world's principal rain forest areas). There has been a measurable decrease in precipitation here, while other areas in the world have had measurable increases.

• Changes in precipitation intensity have occurred. Some areas are having more frequent severe storms. Several areas are experiencing less, but more severe, storm events. This can cause flooding and diminish long-term water supplies.

• The world's temperate zones are experiencing warmer average temperatures. Some areas are experiencing less cold days and frost periods and an increase in heat waves. These conditions stress resources and can also negatively affect people's health.

• The Northern Hemisphere—where most of the Earth's continents are located—is projected to warm more than the projected average.

The IPCC has attempted to increase the awareness of and concern for global warming in all countries of the world. The participating scientists

One effect of global warming is drought. As global temperatures increase, some areas will experience shortages of water, which will have an adverse impact on their ability to grow food, maintain proper hygiene, and maintain good health. This is an especially serious threat to developing countries. (Nature's Images)

Extreme weather events are another result of global warming, such as these multiple cloud-to-ground and cloud-to-cloud lightning strikes during a nighttime electrical storm. (C. Clark, NOAA)

continue to conduct research to further scientific knowledge to enable countries to take the appropriate steps to deal with the problem.

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