The Integration Group continues to reach out to new audiences and develop new perspectives on carbon mitigation. CMI’s best known product is probably the “Princeton wedges.” The wedges work emerged in 2004 from the effort of the project’s two co-PIs, Steve Pacala and Robert Socolow, to reconcile the dissonant evaluations of the urgency of the climate change problem being articulated at that time. On the one hand, environmental scientists were promoting immediate mitigation, while at the same time economists and others involved in integrated assessment were advocating large investments in mitigation in the second half of the century. The wedges work developed the case that humanity already has the tools to “solve” the climate problem if we wish to, at least for the next half-century. Knowing humanity could solve the problem changed the debate: if we can, let’s do it, said many leaders. Paraphrasing Lord Browne writing in Foreign Affairs in 2004, if the costs and damages are comparable and uncertain, let’s get on with the job.


Outreach to climate stakeholders

Co-Directors Pacala and Socolow have continued efforts to inform a variety of stakeholders about the wedges concept and the need to start cutting emissions now. Socolow gave invited testimony to the Senate Finance committee about carbon mitigation strategies, and also gave presentations on carbon mitigation at a Conference on the States and Climate Change, to the U.N. General Assembly, and to the World Bank Executive Directors. Socolow is also a member of a National Academies committee, America’s Energy Future: Technology Opportunities, Risks, and Tradeoffs, which aims to provide authoritative and widely accepted assessments of existing and new energy technologies, their associated impacts, and projected costs. Among other activities, Pacala gave presentations at the Energy Crossroads Conference at Stanford, the International Petroleum Technology Conference in Dubai, and met with the ambassador from Saudi Arabia. He is also deeply involved in development of a new communications organization called “Climate Central” (see below).


The Stabilization Wedges concept and game

Roberta Hotinski, formerly the Information Officer for CMI, is now working for the group as a consultant with primary responsibility for education and outreach based on the “stabilization wedges” concept (please see previous annual reports or the web page cited below for an introduction to the wedges). The wedges continue to grow in popularity and CMI continually receives new requests for permission to reproduce graphics and use other wedges-based materials. There is also high demand for facilitation of the wedges game at workshops and seminars – Hotinski presented the wedges game at ten events this year (including the AAAS Town Hall mentioned above and a meeting of the European Union’s Science & Technology Advisors), reaching hundreds of participants in the business, education, and policy communities. In addition, she has developed a new website combining existing articles, graphics, and game materials as a resource for others wishing to present the wedges concept on their own (see, which receives hundreds of hits per month.

There is growing interest from the informal and K-12 education communities in adapting the wedges to more diverse and younger audiences. The wedges have been included in K-12 climate curricula of the Keystone Group and the World Wildlife Federation, and the teacher’s guide developed by Hotinski has been incorporated into multiple compendia of K-12 climate change materials. Hotinski is also serving on advisory boards for the Franklin Institute in Philadelphia, which is considering using wedges in a new geosciences exhibit, and for the Climate Solutions Project, a proposed large-scale exhibition, discussion forum, and festival centered around solving the carbon and climate problem that will travel around the U.S.


Beyond wedges – focusing on the emissions of individuals

To further promote solutions to climate change, Co-Directors Pacala and Socolow have been developing an approach, as simple as “wedges” in its underlying structure, that could conceivably break the current policy logjam. The new focus is on counting the CO2 emissions rates of individuals, rather than nations, to gain acceptance of the view that those who emit at the same rate, wherever they live, should experience the mitigation effort in similar ways. The goal is to provide a route to a new view of what is “fair,” one that recognizes both that there are wealthy people in poor countries and that poor countries are awash in poverty.

Starting from income distribution data acquired by the World Bank, Pacala and Socolow, along with their post-doc, Shoibal Chakravarty, and collaborators elsewhere, have linked income to carbon to arrive at an emissions curve for all the world’s citizens. Their analysis reveals that, because the 3 billion poorest people in the world together are responsible for only about half a billion metric tons of carbon emissions, the development of the desperately poor is not in conflict with solving the climate problem. In contrast, the 500 million wealthiest people – with incomes above $30,000 – $40,000 (USD) per year – live in all the countries of the world and are responsible for about half of global emissions. To stabilize at an atmospheric CO2 concentration limit of 450 ppm, Pacala and Socolow calculate a personal emissions limit for these rich emitters that falls from about 5 tons to 1 ton carbon per year over 50 years. By basing national caps on the number of emitters above a certain carbon threshold/income level, international policy makers could place the burden of carbon mitigation on those who have benefited economically from high emissions while still taking into account widespread poverty in developing nations.


Climate Central

Co-Director Steve Pacala has also been leading development of a unique non-profit organization, called “Climate Central,” dedicated to providing the public and policymakers with objective, peer-reviewed information about climate change and potential solutions in a manner that the general public can understand. With early funding from the Flora Family Foundation and the 11th Hour Project, Pacala and Jane Lubchenco of Oregon State University have been working to organize and staff the organization.

Intended to be the “Reuters of climate” (in Pacala’s words), Climate Central will have a bureau-like structure (with headquarters in Princeton and the first of several offices in Palo Alto, California) and use the latest communications technology, media expertise, and high quality production facilities to provide rapid response to events as they happen. Berrien Moore, founding director of UNH’s Institute for the Study of Earth, Oceans and Space, has signed on as the group’s executive director, and Heidi Cullen of the Weather Channel and Charlie Lyons, a former writer and producer for ABC News, have also joined the team.