Our calculation of anticipated 2100 global temperature, captured in the Climate Scoreboard, nudged slightly higher with the news of Japan making its mitigation proposal to the UNFCCC conditional on the actions of others.
Reuters reported on Friday that Japanese Environment Minister Sakihito Ozawa announced that Japan’s previous proposals for emissions reductions were premised on “ambitious goals being agreed by all major emitters.” The Climate Scoreboard had previously included Japan’s proposal to reduce emissions to 25% below 1990 levels by 2020 and to 60% below 2005 by 2050. Minister Ozawa’s statement means that Japan’s pledge no longer fits the criteria we use to defined “confirmed” proposals so we have re-estimated the expected temperature increase in 2100 and updated the Climate Scoreboard. Our results indicate that if Japan did not act on it’s previous pledge we would expect an additional 0.1 °C of temperature increase by 2100. We’ll continue to include Japan’s proposal in our estimate of “potential proposals” which includes conditional proposals like this one.
The Climate Scoreboard, the widget that is embedded on more than 1,000 websites around the world, will thus now read 3.9°C (7.0°F), replacing the previous reading of 3.8°C (6.8°F). Given the uncertainty in calculations of global temperature, this change does not indicate a significant shift in the long term outlook for the climate. However, after one week in Copenhagen, there have been no improvements to proposals.
The Scoreboard is based on the C-ROADS (Climate Rapid Overview and Decision Support) computer simulation, which is carefully calibrated to the Intergovernmental Panel on Climate Change Fourth Assessment Report results. C-ROADS emerged from research at the Massachusetts Institute of Technology and allows users to input mitigation proposals for China, India, the US, the European Union, and other nations and regions. It then simulates these emissions’ impacts on greenhouse gas concentrations, temperature change, per-capita emissions, cumulative emissions, sea level rise and other indicators. More information on the simulator is available here.