According to the GCP’s Global Carbon Budget report, published in Nature Geoscience, atmospheric CO2 is now 38 per cent higher than pre-industrial levels, at 385 parts per million, due to the addition of four billion tonnes of CO2 in 2008.

Carbon dioxide emissions from human activities rose two per cent in 2008—slightly slower than the period 2000-2007—to an all-time high of 1.3 tonnes of carbon per capita per year.

Coal was the main source of CO2 increases, with small decreases reported in emissions from oil-based sources and deforestation.

Deforestation now represents only 12 per cent of global emissions, prompting GCP lead author, CSIRO’s Dr Mike Raupach, to comment that there is "limited scope for rich nations to offset emissions by supporting avoidance of deforestation in tropical countries like Indonesia and Brazil".

"CO2 emissions from fossil fuel combustion are estimated to have increased 41 per cent above 1990 levels with emissions continuing to track close to the worst-case scenario of the Intergovernmental Panel on Climate Change (IPCC)," Dr Raupach said.

Land and ocean CO2 sinks, which have removed about half the tenfold increase in CO2 emissions over the past century, are showing signs of faltering.

With changes in the ocean occurring over hundreds or thousands of years, this week’s news locks in ocean acidification and saturation well into the future, according to oceanographer Dr Will Howard of the Antarctic Climate & Ecosystems CRC.

"As we increase the atmospheric concentration of carbon dioxide about a hundred times faster than any time in the past 800,000 years, we outstrip the ability of natural systems to respond," Dr Howard said.

Because of the 2008 La Nina, characterised by cooler and, in some parts of the world, wetter conditions, land sequestration of CO2 was enhanced last year, but is expected to fall off again with the likely onset of an El Nino event late this year.