Few science policy issues today are as complex or divisive as climate change. For that very reason a team of researchers is using the topic as part of a project that seeks to better understand and solve challenging society-level problems by leveraging the collective intelligence of Internet users worldwide.

The Climate CoLab project, developed by the Massachusetts Institute of Technology's (M.I.T.) Collective Intelligence Lab, uses an online forum to encourage institutional and citizen scientists alike to develop proposals for addressing climate change and then improve those proposals based on Web community feedback. The proposals—broken down into "global" and "local" categories—are then judged as part of a multi-phase global competition where the winners are invited to present their ideas to public officials.

This year's competition asks the question: "How should the global economy evolve through 2100, given the risks of climate change?" The competition is in its second phase, during which teams and individuals writing proposals seek to improve upon their original ideas with help from the more than 2,100 members of Colab's online community. After the second phase wraps up on October 31 a team of judges will choose the most practical proposals to move on to the third and final round.

For more citizen science projects visit Scientific American's Citizen Science projects page.

Grassroots projects such as Wikipedia and open-source software serve as an inspiration for the Climate Colab, which was launched in 2009, says Thomas Malone, director of M.I.T.'s Center for Collective Intelligence and the Colab's principal investigator. At the Colab site, people can create proposals using text, images, links or other material that convey the message of what the proposal's creator thinks needs to be done, he says, adding, "That could be changes in economic treaties, political changes or even social changes."

The idea is to come up with workable plans. "In order to keep these proposals grounded in the physical and economic realities that we actually face, each proposal at the global level must also include a quantitative scenario about what that proposal would imply," Malone says. For example, each proposal must include projections quantifying its potential to reduce green house gas and carbon emissions. Proposal writers have access to computer modeling software on the Colab's site to help them come up with the necessary calculations.

One proposal in this year's global category posits that climate policy is too limited and that global problems can be solved as a whole, for example, with a "circular economy," where all used resources are regenerated by nature or industry into new resources. James Greyson, founder of a U.K.-based think tank called BlindSpot and the proposal's creator, has been trading comments with community members since June en route to becoming a finalist in this year's competition. Forty-eight community members have signed on as "supporters" of Greyson's proposal. Another popular global finalist—with 45 supporters—proposes to "mitigate climate change by going meatless."

The most popular proposal in the national category—although it has only eight supporters—suggests installing connected "personal rapid transit" grids over the urban and suburban areas with the densest 50 percent of the U.S. population.

Beginning next week judges and citizen scientists who've signed up as part of the Climate Colab community will vote for their favorite finalists and on November 15 will announce Judge's Choice and People's Choice winners in each category. "We want people to check out the existing proposals, make suggestions and then vote," Malone says.

Last year's winners presented their proposals to the United Nations Secretary General's Climate Change Support Team in New York City and to the U.S. House of Representatives Select Committee on Energy Independence and Global Warming in Washington, D.C.

Image courtesy of Liam Gumley, Space Science and Engineering Center, University of Wisconsin-Madison