International climate panel finds global warming 'unequivocal,' cites human cause

In the most authoritative review of the science surrounding climate change to date, an international panel of climate scientists have announced that global warming is "unequivocal" and the role of humans in the process is now of little doubt. The announcement came with the release of the Intergovernmental Panel on Climate Change (IPCC) report "Summary for Policy Makers" on Feb. 2 in Paris. The report highlights the increased certainty of climate scientists that human activity is the primary driver of current climate change and says that the warmer temperatures are already having widespread effects on the planet's climate as a whole. The IPCC, a team of climate experts from 113 countries, was created in 1988 by the World Meteorological Organization and the United Nations Environment Program. The panel releases reports its reports every five to six years and is considered to be the definitive authority on the present state of the science of climate change. The current report is the first of a series of IPCC reports to be released this year, and has been long-awaited, considering the amount of climate research that has been published since the panel's last report was released in 2001. The report represents the first working group of the IPCC, whose mandate is to determine the extent to which natural and human factors are driving climate change and to study both the predicted and observed effects of warming. While the IPCC does not conduct any new research itself, it undertakes an extensive analysis of all peer-reviewed literature on the subject and its members include some of the most distinguished members of the climate science community. The process involves a lengthy review process in which the working group's draft report is reviewed by thousands of scientists within the group's discipline. The release of the summary report represents one of the final stages of that process, in which delegations from IPCC member countries meet to reach a final consensus in regards to the reports's findings. This review process has been criticized by some who feel that the consensus-based final product is an overly conservative estimate, accepting only the most moderate outlook for climate change. Others, such as Senator James Inhofe (R-OK), said the new report "is a shining example of the corruption of science for political gain." Inhofe and others contend that, as many of the delegates who review the paper prior to its release are not scientists but rather policy-makers, the summary report is "a political document, not a scientific report," though virtually all of the writers themselves are scientists, and leaders of the teams who worked on the various sections of the report are represented in the process. Dr. Sharon Hays, from the White House Office of Science and Technology Policy and leader of the US delegation at the meeting said the report "reflects the sizeable and robust body of knowledge regarding the physical science of climate change." The current assessment, while it does not drastically alter climate predictions made in past IPCC reports, does depart from previous assessments in the level of certainty achieved on whether global warming is occurring, and on the role of humans in that process. The findings, say the scientists, represent an increased understanding of the mechanics of climate change since the 2001 report. The report states that humans are "very likely" a major factor in the current warming, an increase in certainty from the 2001 assessment which found humans to be a "likely" a factor. "There is no doubt that [global warming] is dominated by human activity," said Dr. Susan Solomon, co-chair of the group that wrote the report and a senior scientist at the National Oceanic and Atmospheric Administration. The scientists found that current levels of greenhouse gases, namely carbon dioxide, methane and nitrous oxide "have increased markedly as a result of human activities since 1750 and now far exceed pre-industrial values determined from ice cores spanning many thousands of years." The amount with which carbon dioxide has added heat to the climate system has "increased by 20 percent from 1995 to 2005, the largest change for any decade in at least 200 years." According to the report, with 11 of the last 12 years among the highest global temperatures ever recorded, warming as a result of the increase of greenhouse gases is now indisputable and is "evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global mean sea level." The report also addressed claims by climate skeptics that the increase in recorded temperatures was due to the "urban heat island effect" around temperature gauging stations. It found that the effects are "real but local, and have negligible influence on these values." New analyses of satellite and balloon-borne temperature measurements, also a major source of contention among climate skeptics, have shown "warming rates that are similar to those of the surface temperature record." In predicting the rate at which the temperatures could potentially rise, the report used models based on a variety of scenarios regarding the steps that governments could take to reduce greenhouse gas emissions. Under its most optimistic scenario, in which human populations stabilize and there is an "the introduction of clean and resource-efficient technologies," the global temperature is projected to be 3.2 degrees Fahrenheit higher by 2100. Under the worst-case scenario, in which a "fossil-intensive" culture persists, the IPCC's best estimate is an increase in temperature of 7.2 degrees, with a possible increase of up to 11.5 degrees by 2100. The panel forecasts that, with increasing temperatures, sea levels are predicted to rise by seven to 23 inches by 2100, though this a more moderate estimate than their 2001 report which estimated a sea level rise of 3.5 and 34.6 inches. While the upper end of the new projection is lower, however, the narrowing range suggests improved models and a greater degree of certainty. The IPCC excluded possible variation in the melting rate of land ice in their estimate, due to scientific uncertainty regarding the pace in which this would occur. It did note, however, that projected temperatures for Greenland are comparable to "those inferred for the last interglacial period 125,000 years ago, when paleoclimatic information suggests reductions of polar land ice extent and [13 to 19 feet] of sea level rise." Scientists also suggested that the increased concentration of carbon dioxide in the atmosphere may be leading to an increased acidification of the world's oceans, as carbon dioxide mixes with water and forms carbonic acid. Such a process could have significant negative impacts on some coral species, plankton and fish populations. The report gives its starkest, and most direct, warning regarding the regional impacts of such a shift in temperatures. Even in the best-case scenario, the group predicts that the warming will result in changing wind patterns, extreme heat waves, regional increases and decreases in precipitation, reduction in sea ice and glacial cover–all of which will have significantly negative effects on a wide variety of ecosystems and on humanity as a whole. Given the gravity of IPCC's conclusions on climate change, many politicians throughout the world have begun to call on the world community to end the debate on whether humans are influencing the climate and begin to act to change it. French president Jacques Chirac responded to the report with a call for a new global environmental body to "support the implementation of environmental decisions." Achim Steiner, executive director of the United Nations Environment Program said that "February 2nd will be remembered as the date when uncertainty was removed as to whether humans had anything to do with climate change on this planet.... We are looking for an unequivocal response from politicians."