Scientists said that CO2 emissions have risen by 29% in the past decade alone and called for urgent action by leaders at the UN climate talks in Copenhagen to agree drastic emissions cuts in order to avoid dangerous climate change.
The news will give greater urgency to the diplomatic manoeuvring before the Copenhagen summit. President Obama and President Hu of China attempted to breathe new life into the negotiations on Wednesday by announcing that they intended to set targets for easing greenhouse gas emissions next month. “The global trends we are on with CO2 emissions from fossil fuels suggest that we’re heading towards 6C of global warming,” said Corinne Le Quéré of the University of East Anglia who led the study with colleagues at the British Antarctic Survey.
By studying 50 years of data on carbon emissions and combining with estimates of human carbon emissions and other sources such as volcanoes, the team was able to estimate how much CO2 is being absorbed naturally by forests, oceans and soil. The team conclude in the journal Nature Geoscience that those natural sinks are becoming less efficient, absorbing 55% of the carbon now, compared with 60% half a century ago. The drop in the amount absorbed is equivalent to 405m tonnes of carbon or around 60 times the annual output of Drax coal-fired power station, which is the largest in the UK.
Based on projected changes in GDP, the scientists said that emissions for 2009 were expected to fall to 2007 levels, before increasing again in 2010.
Climatic conditions
The amount of CO2 that natural carbon sinks can absorb varies from year to year depending on climactic and other natural conditions, and this means that overall trends can be difficult to detect.
Le Quéré said her team’s analysis had been able to remove more of the noise in the data that is associated with the natural annual variability of CO2 levels due to, for example, El Niño or volcanic eruptions. The scientists agreed, however, that an improved understanding of land and ocean CO2 sinks was crucial, since it has a major influence in determining the link between human CO2 emissions and atmospheric concentration of the greenhouse gas.
In turn, this has implications for CO2 targets set by governments at climate negotiations.
