Data shows global temperatures aren't rising the way climate scientists have predicted. A new report by an international scientific group has listed human activity as the most likely reason behind global warming observed since the 1950s.
The report by the UN-sponsored Intergovernmental Panel on Climate Change (IPCC) used the strongest words yet on the issue, saying man-made warming was "extremely likely". The full 2,000-page report will not be released until Monday, but a summary with key findings was published at a meeting of the IPCC in Stockholm, Sweden, on Friday.
In its previous assessment, in 2007, the panel had said it was "very likely" that global warming was man-made. It now says the evidence has grown thanks to more and better observations, a clearer understanding of the climate system and improved models to analyse the impact of rising temperatures.
The new predictions are essentially the same as the old ones, albeit a little more precise. The only adjustment the IPCC is making is an increase in the predicted rise of sea levels. The new report forecasts that coastal waters may rise by between 29 and 82 centimeters (11 and 32 inches) by the end of the century. The previous report predicted a rise of 18-59 centimetres.
The IPCC's problem: its climate models should have been able to predict the sudden flattening in the temperature curve. Offering explanations after the fact for why temperatures haven't increased in so long only serves to raise doubts as to how reliable the forecasts really are.
In any case, scientists have discovered some possible indications as to why temperatures are not currently rising. One explanation involves the Pacific Ocean, which, calculations indicate, has absorbed an unusually large amount of heat from the Earth's atmosphere in recent years. If this proves to be true, then the warnings are still in effect. It would mean the greenhouse effect is adding more and more energy into the climate system, exactly as the simulations predict, just with a larger portion of that energy than expected disappearing temporarily into the ocean.
One of the most controversial subjects in the report was how to deal with a purported slowdown in warming in the past 15 years. Climate skeptics say this "hiatus" casts doubt on the scientific consensus on climate change. Environmental policymakers within the IPCC fear, though, that climate skeptics and industry lobbyists could exploit these scientific uncertainties for their own purposes.
The IPCC assessments are important because they form the scientific basis of UN negotiations on a new climate deal. Governments are supposed to finish that agreement in 2015, but it's unclear whether they will commit to the emissions cuts that scientists say will be necessary to keep the temperature below a limit at which the worst effects of climate change can be avoided.
By Guylain Gustave Moke
Photo-Credit: AFP- UN-sponsored Intergovernmental Panel on Climate Change (IPCC)-Photo