BioEd Online

Global carbon emissions are now growing by 3.2% a year, according to results presented at an Earth science conference in Beijing on 9 November. That's four times higher than the average annual growth of 0.8% from 1990-99.

"We are not on any of the stabilization paths," says Michael Raupach, a carbon-cycle scientist with Australia's Commonwealth Scientific and Industrial Research Organization (CSIRO) in Canberra, who presented the Global Carbon Project results.

The result is not particularly surprising there have been many reports of countries missing their national emissions targets. But the tally, using data up to 2005, drives home how far away we are from projections from the Intergovernmental Panel on Climate Change (IPCC) of the emissions levels needed to prevent damaging climate change.

Missing targets

"What's really striking is the rate of growth in places like China," says Raupach. According to Chinese figures, China currently contributes some 16% to global emissions, but accounts for 40% of the growth in world emissions.

China's vice premier Hui Liangyu yesterday told the meeting that China, like all countries, suffers from severe weather events that are in part a result of global warming. "The Chinese government attaches great important to global environmental change and actively copes with the related problems," he wrote in a letter to the meeting delegates.

China plans to reduce the amount of its 'energy intensity', defined as the emissions per person per unit of GDP, by 20% by 2010, although it has no official emissions targets.

Sea-level rise is also at the upper end of IPCC projections, adds John Church, who works at CSIRO Marine and Atmospheric Research in Hobart, Tasmania. Analyses published in 2006 have shown that sea level is currently rising at 1.5-2 mm per year, which is in the upper half of the IPCC value of 1-2 mm per year. The rate of the rise is accelerating.

This is expected to lead to an 88 cm rise in sea level by 2100. "We have to start acting soon it's urgent," says Church. Raupach's results, he says, are "really striking".

New insights

The Global Carbon Project, part of the larger Earth System Science Partnership (ESSP) that is convening in Beijing this week, consists of some 200 researchers worldwide who synthesize and interpret available data.

"The ESSP's role is to put things together, and suddenly you get new insights," says Will Steffen from the Australian National University, Canberra.

The data for global emissions comes mainly from the Carbon Dioxide Information Analysis Center, based at the Oak Ridge National Laboratory in Tennessee. "We are in a place where we can 'nowcast' the carbon cycle," says Raupach. "We're about to publish this for 2005 and we can continue to do that live."

Raupach also told the meeting that, to stabilize atmospheric carbon dioxide levels at 550 parts per million, the world must release no more than 750 gigatonnes of extra carbon into the atmosphere. Even this which is often regarded as a politically realistic target is expected to lead to global warming of more than 2 degrees Celsius on pre-industrial temperatures. The current level is 380 ppm.

Meeting such a target will be extremely tough: emissions from fossil-fuel burning and land-use change currently top 9 gigatonnes a year.

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