Graph - Possibilities for the Global Climate Deal

Below is a graph from C-ROADS.

We collected emissions reductions proposals in the public domain up until March 10, 2009 (called "Current Proposals" in the graph and documented here) – and found that even if  they were fully implemented they would be far from sufficient to meet the goal of stabilizing atmospheric CO2 levels at or below 450 ppm, reaching instead about 730 ppm by 2100.These proposals would not be sufficient to limit warming to 2°C over pre-industrial temperatures, creating instead approximately 4°C of temperature increase by 2100.

"Current proposals" reduce the gap between “Business As Usual” (BAU) and the trajectory required to limit global average temperature to 2°C by less than 50%.

If  the UNFCCC process is to achieve widely accepted climate goals – such as stabilizing CO2 levels between 350-450 ppm and limiting temperature increase to less than 2°C over pre-industrial – then, in the next nine months, emissions reduction proposals are going to need to become significantly more ambitious.

How much more ambitious?

At the very least, as ambitious as the greatest-reducing positions on greenhouse gas mitigation articulated within the official UNFCCC process. The range of positions is summarized in a "note by the chair" of the Ad Hoc Working Group on Long-Term Cooperative Action Under the Convention which was released on March 18 in preparation for the Bonn meeting.

We used C-ROADS to calculate the likely results for the climate if the most ambitious proposals for developed countries contained in that summary (95% below 1990 levels by 2050) were to be combined with its most ambitious proposal for developing countries (25% below 2000 levels by 2050). This scenario is titled “Max FF” in the figure above. Under this scenario, atmospheric CO2 would stabilize in the range of 425 ppm and temperature increase would be in the range of 2.5C.