Southern Ocean saturated with carbon
Anna:
May 27th, 2007
The Southern Ocean cannot continue absorbing carbon at current rates, according to research published in the journal Science last week. The disturbing findings are the result of a four year study of the Antarctic region, conducted by scientists from the University of East Anglia (UEA), British Antarctic Survey (BAS) and the Max Planck Institute.
Oceans are major “carbon sinks”, reservoirs of carbon dioxide which remove quantities of the harmful gas from the atmospheres. The Earth’s natural carbon sinks, oceans and plants, absorb around half of all carbon produced by human activity. The Southern Ocean alone accounts for more than 6% of the world’s ocean carbon storing capacity. Since 1981, the ocean’s ability to hold carbon has been reducing and this carbon sink now appears to be reaching capacity, resulting in a higher level of carbon dioxide in the earth’s atmosphere.
The findings follow hot on the heels of new evidence that the polar ice caps are breaking up, and revelations last year that Siberia’s immense frozen peat bogs are melting. The one million square kilometre area of permafrost is gradually thawing, releasing huge quantities of methane, a greenhouse gas more potent than carbon dioxide. The accelerated rates of carbon dioxide and methane release are interpreted by some scientists as a worrying indication of the speed of anthropogenic climate change.
The Southern Ocean research team found that increased winds over the ocean had triggered a release of stored carbon dioxide. These winds are a new phenomenon, thought to be a result of the ongoing depletion of the ozone layer in the Antarctic. Strong winds lead to increased turbulence and carbon dissolved in deep water is dredged to the surface, where it is released into the armosphere. If the trend continues, this particular carbon sink will become an increasingly ineffective counterbalance to the huge volumes of greenhouse gases being emitted each year. And as the greenhouse effect intensifies, so will the release of carbon, a negative feedback that could have catastrophic long-term consequences. Dr Corinne Le Quéré of UEA and BAS said:
This is the first time that we’ve been able to say that climate change itself is responsible for the saturation of the Southern Ocean sink.
Our planet is ‘gifted’ with around 8 gigatonnes of carbon dioxide annually, thanks to human activities like energy generation and consumption, agriculture and waste disposal. This, surely is an area where the G8 leaders must take the lead. The major produceers of carbon dioxide since the industrial revolution began, the developed world is also responsible for getting emissions under control and encouraging a responsible attitude among emerging economies like China and India. With other studies suggesting that similar processes are occurring in the North Atlantic, now is the time to take action.
As Le Quéré says, serious efforts need to be made to reduce carbon emissions. It’s no good throwing our hands up and accepting that greenhouse gas levels are bound to increase as the world’s population and energy needs grow.