Researchers have developed a new model that specifies the maximum volumes of carbon dioxide that humans may emit to remain below the critical threshold for climate warming of two degrees Celsius.
Researchers at the Max Planck Institute for Meteorology in Hamburg incorporated into their calculations data relating to the carbon cycle, namely the volume of carbon dioxide absorbed and released by the oceans and forests.
The aim of the international ENSEMBLES project is to simulate future changes in the global climate and carbon dioxide emissions and thereby to obtain more reliable threshold values on this basis.
With the help of new models for a prescribed atmospheric carbon dioxide concentration, scientists from all over Europe have now calculated for the first time the extent to which the global carbon dioxide emissions must be reduced to halt global warming.
"What's new about this research is that we have integrated the carbon cycle into our model to obtain the emissions data," said Erich Roeckner.
According to the model, admissible carbon dioxide emissions will increase from approximately seven billion tonnes of carbon in the year 2000 to a maximum value of around ten billion tonnes in 2015.
In order to achieve the long-term stabilisation of the atmospheric carbon dioxide concentration, the emissions will then have to be reduced by 56 percent by the year 2050 and approach zero towards the end of this century.
Although, based on these calculations, global warming would remain under the two-degree threshold until 2100, further warming may be expected in the long term.
"It will take centuries for the global climate system to stabilise," said Roeckner.
The scientists used a new method with which they reconstructed historical emission pathways on the basis of already-calculated carbon dioxide concentrations.
The study is published in Climatic Change. (ANI)