No sooner is the Nobel prize in the bag than the Intergovernmental Panel on Climate Change is coming under fire for not being quick enough on its feet. Levels of atmospheric carbon dioxide are rising faster than any climate models predict, and this has prompted some climate scientists to call for an urgent overhaul of the IPCC.
Key conclusions in the final part of the IPCC’s Fourth Assessment Report on climate change, which it publishes next month, are based on research that is several years old, says Inez Fung at the Berkeley Institute of the Environment, California. For her research to be considered in this year’s report, she had to complete it by 2004. “There is an awful lag in the IPCC process,” she says.
In some cases, the time lag is even greater. “The most recent IPCC special report on emission scenarios was published in 2000, and the data it contains were probably collected in 1998,” says Gregg Marland of the International Institute for Applied Systems Analysis in Laxenburg, Austria.
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“The most recent IPCC report on emissions scenarios contains data that were probably collected in 1998”
The IPCC’s emissions estimates in that report are now out of date. In the 1990s, energy efficiency initiatives led to a drop in carbon intensity – the ratio of CO2 emissions to gross world product. The IPCC emission scenario, still widely used by climate modellers, suggests that trend will continue.
A new assessment by Marland and his colleagues argues otherwise. They have shown that carbon intensity has increased since the year 2000, largely fuelled by the economic growth of China and India.
Meanwhile CO2 sinks, which in the past have absorbed up to half of the carbon emissions for which humans are responsible, are no longer growing fast enough to keep pace. As a result, levels of atmospheric CO2 are outstripping what climate models predict. Marland concludes that the carbon cycle will have a stronger effect on the climate than has been expected (, DOI: 10.1073/pnas.0702737104).
“The projections in the 2007 IPCC report [using the 2000 emission scenarios] are conservative, and that’s scary,” says Fung. Marland acknowledges that the IPCC is beginning to build a new set of energy scenarios, but Fung sees this as no more than a stopgap solution.
“A lot of us have been talking about how to make [the IPCC] into a holistic, fully interactive system,” she says. This is not just a problem with the IPCC, she stresses. “We need the scientific community to reorganise itself,” she says.
Jayant Sathaye, an IPCC author, says that in future, energy scenario data will be given to climate modellers sooner and updated regularly. He points out that researchers do not have to wait for the IPCC to publish its scenarios, however. “All the IPCC does is review the results. No one is forcing authors to use IPCC reports,” he says.
Another climate change institution, the Kyoto protocol, has also been attacked this week. It is described by Gwyn Prins at the London School of Economics and Steve Rayner at the University of Oxford as the “wrong tool for the job” (Nature, vol 449, p 973). They argue that the Kyoto strategy was too simplistic: “Climate change is not amenable to an elegant solution because it is not a discrete problem,” they say. Prins and Rayner identify five essential elements for a post-Kyoto agreement, including an acceptance that money should be spent on adapting to the changing climate.
