In a new discussion paper, authors Richard Schmalensee, professor of economics at the Massachusetts Institute of Technology, and Robert N. Stavins, director of the Harvard Project on Climate Agreements, explore four ironic outcomes associated with the otherwise very successful sulfur-dioxide cap-and-trade system created by the Clean Air Act Amendments of 1990.

The outcome of the December 2011 United Nations climate negotiations in Durban, South Africa, provides an important new opportunity to move toward an international climate policy architecture that is capable of delivering broad international participation and significant global CO2 emissions reductions at reasonable cost. This paper addresses an important component of potential climate policy architecture for the post-Durban era: links among independent tradable permit systems for greenhouse gases.

Various journalists and advocates have, of late, described America's Regional Greenhouse Gas Initiative (RGGI) as being near "the brink of failure" thanks to the trend of very low prices of permits to emit carbon dioxide. Likewise, commentators have claimed that Europe's carbon market, the European Union Emission Trading Scheme (EU ETS), may be "sinking into oblivion" because its emissions allowances too have become very cheap. 

The outcome of the December 2011 United Nations climate negotiations in Durban, South Africa, provides an important new opportunity to move toward an international climate policy architecture that is capable of delivering broad international participation and significant global CO2 emissions reductions at reasonable cost. We evaluate one important component of potential climate policy architecture for the post-Durban era: links among independent tradable permit systems for greenhouse gases.

The introduction of the U.S. SO2 allowance-trading program to address the threat of acid rain as part of the Clean Air Act Amendments of 1990 is a landmark event in the history of environmental regulation. The program was a great success by almost all measures. Ironically, cap and trade seems especially well suited to addressing the problem of climate change, in that emitted greenhouse gases are evenly distributed throughout the world's atmosphere. Recent hostility toward cap and trade in debates about U.S. climate legislation may reflect the broader political environment of the climate debate more than the substantive merits of market-based regulation.

"...[I]t remains true that cap-and-trade is still the most likely domestic policy approach for CO2 emissions reductions throughout the industrialised world, given the rather unattractive set of available alternative approaches.  This makes it important to think about the possibility of linking these national and regional cap-and-trade systems in the future.  Such linking occurs when the government that maintains one system allows regulated entities to use allowances or credits from other systems to meet compliance obligations."

Harvard Project on Climate Agreements Director Robert N. Stavins delivered a presentation titled "Climate Change: Efficiency and Equity," at The Graduate Institute in Geneva, Switzerland, on November 29, 2011. The talk was one in the Geneva Environmental Dialogue Series of public keynote lectures that the Institute holds annually on a theme related to the international environment. The theme for the 2011–2012 term is "Justice and the Environment."

Because of the global commons nature of climate change, international cooperation among nations will likely be necessary for meaningful action at the global level.  At the same time, it will inevitably be up to the actions of sovereign nations to put in place policies that bring about meaningful reductions in the emissions of greenhouse gases.  Due to the ubiquity and diversity of emissions of greenhouse gases in most economies, as well as the variation in abatement costs among individual sources, conventional environmental policy approaches, such as uniform technology and performance standards, are unlikely to be sufficient to the task.  Therefore, attention has increasingly turned to market-based instruments in the form of carbon-pricing mechanisms.  We examine the opportunities and challenges associated with the major options for carbon pricing:  carbon taxes, cap-and-trade, emission reduction credits, clean energy standards, and fossil fuel subsidy reductions.

In this policy brief, Harvard Project Director Robert Stavins focuses on how subnational policies will interact with a federal climate policy. It turns out that some of the interactions will be problematic, others will be benign, and still others could be positive. He also examines the role that could be played by subnational policies in the absence of a meaningful federal policy, with the conclusion that—like it or not—we may find that Sacramento, California comes to take the place of Washington as the center of national climate policy. This case study might provide insight for COP 17 delegates in designing the next steps toward a flexible international agreement.

Market-approaches to reducing emissions of greenhouse gases lie at the heart of any cost-effective set of policies put forward in an international agreement—and will be considered at COP 17 in Durban in both the Kyoto and Long-term Cooperative Action discussions. Joseph Aldy and Robert Stavins "examine the opportunities and challenges associated with the major options for carbon pricing: carbon taxes, cap‐and‐trade, emission reduction credits, clean energy standards, and fossil fuel subsidy reductions."