The world is on course for the "worst case" scenario of global warming, with average worldwide temperatures increasing by between 4C and 6C in the coming century, according to the latest analysis of how much man-made carbon dioxide is being pumped into the atmosphere.
Latest figures on CO2 emissions show that the global financial crisis of 2008-2009 has had virtually no impact on the long-term increase in greenhouse gases released from the burning of fossil fuels, deforestation and other industrial activities.
The amount of man-made carbon dioxide released in 2010 reached a record 10 billion tonnes, nearly 6 per cent higher than in 2009. It has returned the world to a path of ever-higher emissions that will make it increasingly difficult to keep within the 2C target that most experts believe is necessary to avoid dangerous climate change.
Unlike previous global recessions, which caused long-term dips in carbon dioxide emissions lasting several years, the recent recession caused just one year's fall of 1.9 per cent, which was quickly reversed by a dramatic rebound of 2010 and 2011, said Professor Corinne Le Quéré of the Tyndall Centre for Climate Change Research at the University of East Anglia.
"Global CO2 emissions since 2000 are tracking the high end of the projections used by the Intergovernmental Panel on Climate Change (IPCC), which far exceed 2C warming by 2100," Professor Le Quéré said.
"Yet governments have pledged to keep warming below 2C to avoid the most dangerous aspects of climate change such as widespread water stress and sea level rise, and increases in extreme climatic events," she said.
"The take-home message coming out from these figures is that people are not understanding the scale of the changes that are needed to limit the temperature change to within the 2C target," she added.
Despite the attempts to curb carbon dioxide emissions under the Kyoto Protocol and Copenhagen Accord, and eventually to cut them to below 1990 levels, the fast-growing economies of the developing world, particularly China and India, have ensured the overall trend continues to accelerate upwards.
The last decade has seen an unprecedented increase in greenhouse gases released from fossil fuels, deforestation and the manufacture of cement, resulting in an average rise of 3.1 per cent per year. This compares with an annual increase of just 1 per cent per year during the 1990s.
Overall, the global emissions of carbon dioxide from man-made sources have increased by nearly 50 per cent over the past two decades, culminating in the release of a record 10 billion tons of carbon dioxide in 2010. The trend has continued on the same trajectory during 2011, Professor Le Quéré said.
"There has been a complete rebound during 2010 and we are now on the same trajectory we were before the global financial recession of 2008-2009. These are huge growth rates and it looks like it is a trend that is here to stay," Professor Le Quéré said.
"We are now tracking the high end of the worst case scenario of the IPCC. At the moment we are very far away from keeping within the target of a 2C increase in global temperatures by the end of the century. We are more on course for a 4C rise, and possibly as high as 6C if carbon feedbacks begin," she said.
There are already signs of such feedbacks. In 2008, an estimated 45 per cent of man-made carbon dioxide emissions remained in the atmosphere, with the rest being absorbed by natural "sinks" on land and sea. In 2010, about 50 per cent of man-made carbon dioxide remained in the atmosphere, with the natural sinks appearing less effective than in previous years.
The study was carried out by the Global Carbon Project, a consortium of climate scientists and economists from around the world and published in the journal Nature Climate Change. It found that the global recession has had a far bigger impact on the carbon emissions of the developed world than those of the developing world.
In the developed world, carbon dioxide emissions fell by 1.3 per cent in 2008 and fell again by 7.6 per cent in 2009, rising by 3.4 per cent in 2010. Whereas in the developing world, dominated by China, emissions actually increased by 4.4 per cent in 2008, increased by 3.9 per cent in 2009 and 7.6 per cent in 2010, according to the study.
Glen Peters of the Centre for International Climate and Environmental Research in Norway, a lead author of the study, said that in some ways the global financial crisis was a missed opportunity in terms of attempting to curb future carbon dioxide emissions.
"Many saw the global financial crisis as an opportunity to move the global economy away from persistent and high emissions growth, but the return to emissions growth in 2010 suggests the opportunity was not exploited," Dr Peters said.