Stormy weather ahead for the climate

  • Researchers with the Intergovernmental Panel on Climate Change (IPCC) and representatives from about one hundred countries met in Stockholm.
  • On Friday, they will adopt the fifth report on climate change.
  • Confirmation and clarification of findings.

The verdict is rendered every five years. In 1990, the first version was a little over 400 pages. The report to be presented in Stockholm will be over 2,000 pages long. This is a much-awaited document. It’s the best summary of knowledge on climate change. Where do we stand at this time? What is the conclusion of this very extensive research? The IPCC, a group of intergovernmental experts on climate change, is at the helm of this project. The United Nations created this assembly of scientists in 1988, and it has been meeting in a former brewery in the center of the Swedish capital since Monday along with delegates from over 110 countries. They will render their conclusions on Friday in the form of a highly detailed scientific report and a shorter more accessible “summary for the decision makers.” The process has been a long and fierce line-by-line battle.

What’s new since 2007? The new IPCC report adds a layer of certainty to what it has collected over the years. Yes, the surface temperature of the planet continues to increase. The “threshold” that was observed over the last fifteen years shows that global warming is only slowing, but in no way stopping. “The latest statistics seem to show that the temperature is once again rising,” states a Belgian climatologist. Yes, greenhouse gases, mostly CO2, are to blame. Neither solar activity nor any other theory can explain the high degree of the warming that has been observed. And an emphatic Yes, it’s indeed human activity that is causing it, “Just as surely as tobacco is bad for health.”

On Friday morning we will know what the scientists and government delegates have concluded. They won’t differ much from the 2007 conclusions. The preceding report predicted that by the end of the century, the temperature will have risen between 1.8ºC and 4ºC depending on the change in greenhouse gases. The ocean level will rise between 18 and 59 centimeters. “The level of uncertainty has not fundamentally diminished,” states Thierry Fichefet (UCL), one of the Belgian authors. This uncertainty is mostly related to future changes in greenhouse gas effect emissions. Four possible scenarios came out of this. The most optimistic one assumes that radical CO2 emission reduction policies are quickly implemented. This could limit temperature increase to 2ºC by the end of the century.

Policy-fiction

Some numbers were revised upwards. “This is mainly due to the melting ice caps’ contribution to the elevation of ocean levels. These had not been factored in before now,” says Fichefet. There is further progress in the degree of confidence in the predictions. “The models have improved”, explains an expert. Fichefet confirms, “The models do a better job of accounting for vegetation, sea ice, aerosol chemistry, and clouds. Their spatial resolution is much higher.”

“The behavior of the ice packs and ice caps is better understood,” emphasizes Jean-Louis Tison, glaciologist with ULB. “We have confirmation that the arctic ice floes are continuing to disappear by about 10% per year. In Antarctica it’s stable, or it may have increased slightly (0.8%) with wide regional discrepancies. The melting ice caps contribute directly to the elevation of the ocean levels. There is a net loss of mass in the Arctic as well as in Antarctica over the last decade.” 

The report does not sidestep the remaining doubts. It also remains careful concerning the future. Too careful, according to some. More recent research is resulting in higher numbers than those of the UN experts. The IPCC will issue a new warning in Stockholm. The present CO2 emission levels are driving the end of century temperatures noticeably higher than the 2ºC threshold over the pre-industrial age average. This is a situation in which the climatic system could become unpredictable, and the impact of warming could be very significant. The global warming skeptics have no intention, for all that, to lay down their arms. And in public opinion, the topic is no longer a concern.

MICHEL DE MUELENAERE

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