Best Effort Global Warming Trajectories

This is a "what if" tool for global warming policy makers. The policy contains just two parameters: the approximate number of (transition) years needed by the world to firmly decrease its annual carbon emissions, and the maximum annual emission reduction effort after that time, expressed in terms of Pacala–Socolow "wedges". Here "effort" is the additional emission reduction effort after all increases of future energy demands have already been met by carbon-free technologies. (So the Pacala-Socolow immediate/seven-wedge strategy is a strategy of zero transitions/zero wedges for the next 50 years).

The purple curve is the world's annual carbon emission rate, the blue curve is the trajectory, and the black dashed line is the popular "doubling" target ceiling. All three curves share the same ordinate. The unit GtC stands for billions of metric tons of carbon.