Researchers at the Max Planck Institute for Meteorology in Hamburg have calculated the amount of carbon dioxide humans can safely emit before effecting the heating of the Earth.

Scientist Erich Roeckner and his team have created a model that determines the highest volumes of carbon dioxide that humans are allowed to emit in order to ensure that Earth does not heat up by more than two degrees Celsius, which is the gate to climate warming. They've used the methodology proposed by the Intergovernmental Panel on Climate Change (IPCC) in order to reconstruct historical emission pathways "on the basis of already-calculated carbon dioxide concentrations." 

In order for this to occur, carbon cycle data, such as the volume of carbon dioxide absorbed by forests and oceans, is added to the model. The model then simulates the evolution of carbon dioxide emissions in order to understand what the future holds and how it should be changed to prevent warming. 

The model is based on a low-resolution spatial grid with 400 kilometer grid spacing. With this kind of model, the land surface, ocean, sea ice, atmosphere and terrestrial and marine carbon cycle are all included in the study.

According to the model, carbon dioxide caused by fossil fuels must be reduced to almost zero by the end of the century to achieve long-term goals of carbon concentration stabilization in the atmosphere. The model calculated that, since the beginning of the Industrial Revolution, fossil carbon dioxide has increased by 35 percent.

Other figures the model has calculated is that carbon emissions will increase from seven billion tonnes in 2000 to 10 billion tonnes in 2015. Then, emissions will have to be decreased by 56 percent by 2050, and reach zero by the end of the century for long-term stabilization to be achieved. But even if these goals are met, global warming would only stay below two degrees Celsius until 2100, and further measures will need to be taken to control warming. 

Roeckner noted that it will take centuries to stabilize the global climate system, and that their data is being studied and evaluated at other climate centers in Europe. 

"As soon as all of the results are available, we can evaluate the spread between the models," said Roeckner. "The more significant the data we have, the more accurate our forecast will be."

In other news, a University of Georgia marine chemist, Wei-Jun Cai, just disproved that melting ice at the poles will allow open water to catch carbon dioxide from the the air. According to a survey of waters in the Canada Basin, the potential carbon dioxide "sink" would be a very short period of time with minor effects due to the amount of rising emissions. 

The study was published in the July 2010 edition of Science.