CLIMATE CHANGE: Danger of Global Warming As Official As It Can Get

By Julio Godoy Reprint | | Print |

Julio Godoy

PARIS, Feb 2 2007 (IPS) - Stark warnings over the damaging effect of impending climate change were underlined in the release Friday of the fourth assessment of the Intergovernmental Panel on Climate Change (IPCC).

“Warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global mean sea level,” says the report ‘Climate Change 2007: The Physical Science Basis’.

The paper reiterates the body’s earlier conclusion that climate change is a consequence of rising atmospheric concentrations of human-made greenhouse gases such as carbon dioxide, methane and nitrous oxide.

“Global atmospheric concentrations (of greenhouse gases) have increased markedly as a result of human activities since 1750 and now far exceed pre-industrial levels,” the paper says.

“The global increases in carbon dioxide concentration are due primarily to fossil fuel use and land-use change, while those of methane and nitrous oxide are primarily due to agriculture.”

According to the IPCC, global atmospheric concentration of carbon dioxide has increased from a pre-industrial value of about 280 parts per million (ppm) to 379 ppm in 2005.

This concentration has increased sharply in recent years. With an average increase of 1.9 ppm a year over the last ten years, the annual carbon dioxide concentration growth rate is larger than ever since the beginning of atmospheric measurements.

The corresponding average growth in concentration between 1960 and 2005 was 1.4 ppm per year. “Eleven of the last twelve years (1995 -2006) rank among the 12 warmest years…since 1850,” the report says.

Global warming has doubled over the last 50 years, the report says. “The linear warming trend over the last 50 years is nearly twice that for the last 100 years,” the panel found. It warns that global temperatures could rise by 6 degrees this century.

The paper adds that global warming will lead to an increase in weather catastrophes such as hotter summers, warmer winters, droughts, melting of glaciers, rising of sea levels, inundations, decimation of biological diversity – and eroding of the very basis of human existence.

The report assesses the current scientific knowledge of the natural and human drivers of climate change, observed changes in climate, the ability of science to attribute changes to different causes, and projections for future climate change.

The IPCC, a group of scientists and government representatives from 110 countries met in Paris Jan. 29-Feb 2 to review the final draft of the body’s fourth assessment.

The original report was produced by some 600 authors from 40 countries. About 620 expert reviewers and a large number of government officials gave their inputs.

At a press conference closing the meeting in Paris Friday, IPCC head Rajendra Pachauri called the report a “very impressive document that goes several steps beyond previous research.”

Achim Steiner, head of the United Nations Environmental Programme said “it is unequivocal now that the burning of fossil fuels is fundamentally changing our climate.”

Steiner said the new IPCC report “should shift (human collective action on climate change) from doubting to having to act” to reduce greenhouse gases. Any other response would be “irresponsible”, Steiner said.

The IPCC conclusions come as no surprise, as present evidence on global warming continues to increase, based on scientific and empirical evidence.

This was not the case in 2001 when the IPCC released its third assessment on global warming. It already warned then that continuing greenhouse emissions would lead to rising global temperatures and to weather catastrophes. At the time some scientists dismissed the report as exaggerated.

In early 2005 U.S. meteorologist Christopher Landsea resigned from the IPCC preparations of its fourth assessment. “I personally cannot in good faith continue to contribute to a process that I view as both being motivated by pre-conceived agendas and being scientifically unsound,” Landsea wrote in an open letter to the ‘scientific community’ Jan 17. 2005.

But Susan Solomon, a top U.S. government scientist who took part in the IPCC deliberations said, “There can be no question that the increase in greenhouse gases are dominated by human activities.”

Some scientists argue that the IPCC report is too cautious, and underestimates real global warming and its consequences.

Stephan Rahmstorf, a leading German climate researcher, warns that by the end of this century sea level could rise between 50 and 140 centimetres above the level measured in 1990. The IPCC in its fourth assessment predicts sea levels to rise between 28 and 43 cm.

Sea level is rising at 3 cm per decade, faster than projected in the IPCC scenarios, Rahmstorf told IPS.