The Greenhouse Gamble™ wheels were developed by the MIT Joint Program on the Science and Policy of Global Change to better convey uncertainty in climate change prediction. The roulette-style spinning wheels depict the estimated probability, or likelihood, of potential temperature change (global average surface temperature) over the next 100 years. The face of each wheel is divided into colored slices, with the size of each slice representing the estimated probability of the temperature change in the year 2100 falling within that range.

The Greenhouse Gamble wheel on the left is the "no policy" or reference case, in which it is assumed no action is taken to try to curb the global emissions of greenhouse gases. The median value of the "no policy" wheel, or the temperature at which there is a 50% chance of falling above or below that level (even odds) is 5.2 °C.
The Greenhouse Gamble wheel on the right is the "with policy" case, which assumes that policies are enacted to limit cumulative emissions of greenhouse gases over the century to 4.2 trillion metric tons, measured in CO2-equivalent. The median warming level (even odds) is 2.3 °C.

The resulting change in probabilities when switching from a "no policy" scenario to a "with policy" scenario is shown by the altered size of the representative temperature slices. If policies to reduce greenhouse gas emissions are enacted, the likelihood of constraining global temperature change in 2100 to below 3 °C warming increases to 90% (9 in 10 odds) from the "no policy" scenario. As global emissions of greenhouse gases continue to increase, the "no policy" roulette wheel continues to spin. By reducing emissions, we can limit the risks from global climate change impacts.

For more information on the Greenhouse Gamble Wheels and the research behind them, please click here.

See MIT News Release for more details.

Inaugural Spin

The Greenhouse Gamble wheel premiered with an auspicious whirl by (then) President of MIT, Charles M. Vest, at the 25th Anniversary Symposium of the Office of Science and Technology Policy on May 1, 2001.

 President Vest's sure-handed tug launched a twirl spanning several seconds, while the auditorium filled with former Presidential Science Advisors anxiously awaited a result. When the revolutions finally slowed, the pointer came to rest on an optimistically cool slice: an increase of only 2 to 3°F. With a facetious grin and a triumphant thrust of both fists upward, Chuck exclaimed: "I saved the world!" The crowd cheered.