The problem: people generally have very little perspective of the actual scale of the contributing components of climate change or the effects of different proposed measures to stop it. What percentage of CO2 emissions are a result of city residential electrical consumption vs agriculture vs vehicles? How much of a difference will legislation X make in the big picture? When Obama says that the United States will cut greenhouse gas emission 80% by 2050 what kind of effect does that actually have? What would happen to the weather in 10 years if everyone in the world stopped driving tomorrow?
The solution: Let people build hypothetical scenarios themselves. Design an interface centered around an attractive time line graph indicating climate data in all its various forms including temperature increase, carbon emissions, and sea level. Curious users can click on and off different proposed solutions to see the real overall effect on projected emissions along with dollar cost over time. Group data in terms of current relevancy such as proposals being discussed at the climate summit in Copenhagen this week. Include competing predictions from different agencies and scientific groups to communicate the level of uncertainty.
Extra credit for building a system to automatically pull in current data from a variety of sources.