Environmental Issues > Global Warming Main Page > All Global Warming Documents

Antarctic Ice Shelf Collapses
National Snow and Ice Data Center
Satellite Spies on Doomed Antarctic Ice Shelf
British Antarctic Survey
(March 2002)

Scientists say the dramatic disintegration of a Rhode Island-sized ice chunk off the Antarctic Peninsula earlier this year is most likely the result of global warming. "With the disappearance of ice shelves that have existed for thousands of years, you rather rapidly run out of other explanations," Dr. Theodore A. Scambos, a glaciologist at the National Snow and Ice Data Center, told The New York Times after the Larsen B shelf collapsed. ("Large Ice Shelf in Antarctica Disintegrates at Great Speed," March 20, 2002.) Scambos and other researchers said it was the first time in thousands of years that the east coast of Antarctica had seen such sharp rises in temperature and dramatic ice loss. Over the last 50 years, average temperatures in the Antarctica Peninsula have risen by 4.5 degrees Fahrenheit (2.5 degrees Celsius), four times the global average. The unprecedented warming has led to a pattern of ice shelve loss on the eastern side of the Peninsula not seen in 12,000 years, researchers said. Scientists said they were also shocked by the speed with which the Larsen B shelf disintegrated -- 1,200 square miles (3,000 square kilometers) in 35 days.

• For more information: Antarctic Ice Shelf Collapses (NSIDC website); Satellite Spies on Doomed Antarctic Ice Shelf (BAS website)

Other recent studies found cooling in central Antarctica, including a January 13, 2002 report in Nature (Peter T. Doran) and the January 18, 2002 issue of Science Magazine (Slawek Tulaczyk). Critics have used these studies to claim global warming is not taking place. However, the authors of the Science and Nature studies reject such claims. Variations in temperature will exist across any large landmass. The researchers add that their data shows only that the effects of global warming on Antarctica may prove harder to forecast than anticipated. Doran told the San Francisco Chronicle that, contrary to the insinuations, "global warming is real and happening right now." ("Media Goofed on Antarctic Data," February 4, 2002.)

Climate of 2001 - Annual Review
National Climate Data Center
WMO Statement on the Status of the Global Climate in 2001
World Meteorological Organization
(December 2001)

Both these scientific bodies found earth's temperature for 2001 to be the second hottest on record. In addition, nine of the 10 warmest years since measurements were first kept in 1860 have occurred since 1990, according to the World Meteorological Organization (WMO). The WMO also found that temperatures are currently rising three times as fast as in the early 20th century. The agency attributed much of the warming to heat-trapping gases like carbon dioxide caused by the burning of fossil fuels. "There are skeptics on everything, but certainly the evidence we have today shows we do have global warming, and that most of this is due to human action," Ken Davidson, the director of the WMO's climate program told The New York Times after the release of the report. The hottest year on record, according to the organizations, was 1998, when average global temperatures were 58.1 degrees Fahrenheit. Average temperature for 2001 was 57.8 degrees, according to the National Climatic Data Center.

• For more information: NCDC website; WMO website

Climate Change Science: An Analysis of Some Key Questions
National Academy of Sciences
(June 2001)

This report was requested by President Bush to determine whether mankind's actions were causing global warming. The answer was a resounding 'yes.' The blue ribbon panel found that "greenhouse gases are accumulating in earth's atmosphere as a result of human activities, causing surface air temperatures and subsurface ocean temperatures to rise." "Temperatures are, in fact, rising," the report adds. The unanimous 11-member panel, which included previous skeptics about global warming, said increasing temperatures posed a problem to humans and ecosystems around the globe. They also said the problem was getting worse. In addition, the panel stated scientific confidence was "higher today than it was 10 or even 5 years ago" that increased greenhouse gas concentrations were to blame for earth's one degree temperature increase over the last 50 years. Human-induced warming and associated sea level rise are expected to continue through the 21st century, the group said, and national policy decisions made now will influence the extent of the damage suffered by humans and ecosystems later in this century.

• For more information: Full study

Climate Change 2001: The Scientific Basis
Climate Change 2001: Impacts, Adaptation and Vulnerability
Intergovernmental Panel on Climate Change
(January and February 2001)

This United Nations-sanctioned panel of hundreds of scientists released two landmark reports on climate change at the beginning of 2001. The first, known as the Working Group I Report on the scientific basis of climate change, states unequivocally that pollution (mainly from the burning of fossil fuels) causes climate change. "Emissions of greenhouse gases...due to human activities continue to alter the atmosphere in ways that are expected to affect the climate," the study says. Global warming has caused sea levels to rise, ocean heat content to increase, and snow cover and ice extent to decrease, according to the study. This and other evidence led the panel to conclude that "there is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities." The report also predicts that earth's average temperature could rise by 3 to 10 degrees Fahrenheit over the next 100 years. That increase would mark the most rapid change in 10 millennia. It would also be as much as 60 percent higher than the IPCC predicted less than six years ago. The study found that warming in the 20th century was most likely the greatest of the last 1,000 years, and that the 1990s was the hottest decade of the last millennium.

The second report, "Climate Change 2001: Impacts, Adaptation and Vulnerability," is the most comprehensive look yet at the existing and long-term effects of global warming. It predicts that rising temperatures caused by the burning of fossil fuels could cause large-scale and irreversible climate changes. Those changes include altered ocean currents, slowed circulation of warm water in the North Atlantic and a vast reduction of mountain glaciers and the Greenland ice sheet. The study also warns of savage floods, disrupted water supplies, droughts, violent storms and the spread of cholera and malaria as temperatures rise over the next century. Poor countries, particularly those in Latin America, Africa and Asia would bear most of the burden of extreme climate changes, which would further widen the gap between poor nations and rich ones, the report concludes. "Most of earth's people will be on the losing side," IPCC Co-Chair and Harvard environmental scientist James McCarthy said of the study's findings.

• For more information: IPCC website

Climate Change Impacts on the United States
National Assessment Synthesis Team
(December 2000)

This study, ordered by Congress in 1990, offers the first comprehensive assessment of how human-induced global warming will affect the United States. The forecast is gloomy. "Increasingly, there will be significant climate-related changes that will effect each one of us," the study states. According to the report, if we don't curb our emissions of heat-trapping gases like carbon dioxide, temperatures will rise between 5 and 10 degrees Fahrenheit over the next century. That increase will cause, for example, alpine meadows in the Rocky Mountains to disappear, sugar maple trees to vanish in the Northeast, and greater risk from storm surges in the Southeast. Rising temperatures will also exacerbate water shortages (especially in the West) and cause New York City to steam in the summer like Atlanta does now. Other likely impacts: coastal erosion, destructive storm surges and the disappearance of barrier islands, all due to rising sea levels.

• For more information: Full study

Climate Extremes: Observations Modeling and Impacts
Science v. 289: 2068-2074
(September 2000)

Extreme weather events such as droughts, floods, heat waves and heavy rainfall are expected to increase over the next 100 years, according to a team of scientists from the National Climatic Data Center. Lead author David Easterling notes that these changes will continue to increase with the rise of "ever greater amounts of GHGs in the atmosphere." Easterling and his colleagues reached their conclusion after reviewing hundreds of studies that used data and climate models to examine past and future changes in climate extremes. The report found that such extreme events will cause sharply increased financial losses in the United States and are likely to lead to the extinction of more plant and animal species.

• For more information: Extreme Weather Events to Continue and Likely Increase; Effects on Society More Intense (NOAA website)

Causes of Climate Change Over the Past 1,000 Years
Science v. 289:270-277
(July 2000)

Humans are the dominant force behind the sharp global warming trend seen in the 20th century, according to this analysis of the climate over the last 1,000 years. The report found that natural factors like volcanic eruptions and fluctuations in sunshine, which were powerful influences on temperatures in past centuries, can account for only 25 percent of the warming since 1900. The rest of the warming was caused by human activity, particularly rising levels of carbon dioxide and other heat-trapping gases, according to the study's author, Texas A&M geologist Thomas J. Crowley. Crowley notes that "natural variability plays only a subsidiary role in the 20th century warming and that the most parsimonious explanation for most of the warming is that it is due to the anthropogenic increase in greenhouse gases" (GHGs). The study presents the most direct link to date between people and the 1.1 degree Fahrenheit rise in average global temperatures over the last 100 years.

• For more information: Full study

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