Regulation of greenhouse gas emissions may proceed by linking together multiple national cap-and-trade systems.
Despite the death in the U.S. Senate last year of serious consideration of an economy-wide cap-and-trade system for carbon dioxide (CO2) emissions – and the apparent political hiatus of such consideration at least until after the November 2012 elections – a major cap-and-trade system for greenhouse gas (GHG) emissions is in place in the European Union; similar systems are in place or under development in New Zealand, California, and several Canadian provinces; systems are being considered at the national level in Australia, Canada, and Japan; and a global emission reduction credit scheme – the Clean Development Mechanism (CDM) – has an enthusiastic and important constituency of supporters in the form of the world’s developing countries.
So, despite the fact that there has been an undeniable loss of momentum due to recent political developments in Australia, Japan, and the United States, it remains true that cap-and-trade is still the most likely domestic policy approach for CO2 emissions reductions throughout the industrialized 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.
Thinking About Linkage
In 2007, with support from the International Emissions Trading Association (IETA) and the Electric Power Research Institute (EPRI), Judson Jaffe and I analyzed the opportunities and challenges presented by linking tradable permit systems. Jaffe was then at Analysis Group in Boston, and is now at the U.S. Department of the Treasury. We presented our findings at the thirteenth Conference of the Parties of the U.N. Framework Convention on Climate Change in Bali, Indonesia, in December, 2007. In 2010, Matthew Ranson (a Ph.D. student in Public Policy at Harvard), Jaffe, and I expanded on these ideas in an article that was published in Ecology Law Quarterly, “Linking Tradable Permit Systems: A Key Element of Emerging International Climate Policy.” In today’s essay, I summarize the highlights of this complex, yet important topic.
First, for anyone new to this territory, let me review the basic facts. Tradable permit systems fall into two categories: cap-and-trade and emission reduction credits. Under cap-and-trade (CAT), the total emissions of regulated sources are capped and the sources are required to hold allowances equal to their emissions. Under a credit system, entities that voluntarily undertake emission reduction projects are awarded credits that can be sold to participants in cap-and-trade systems.
The Merits of Linking
By broadening markets for allowances and credits, linking increases the liquidity and improves the functioning of markets. Linking can reduce the costs of the linked systems by making it possible to shift emission reductions across systems. Just as allowance trading within a system allows higher-cost emission reductions to be replaced by lower-cost reductions, trading across systems allows higher-cost reductions in one system to be replaced by lower-cost reductions in another system.
Other Implications
Along with the cost savings it can offer, linking has other implications that warrant serious consideration. Under some circumstances, linked systems collectively will not achieve the same level of emission reductions as they would absent linking. This can result either from a link’s impact on emissions under the linked systems, or from its impact on emissions leakage from those systems. Linking also has distributional impacts across and within systems. And linking can reduce the control that a country has over the impacts of its tradable permit system. In particular, when a domestic CAT system is linked with another CAT system, decisions by the government overseeing the other system can influence the domestic system’s allowance price, distributional impacts, and emissions.
By the way, linkage can also occur among a heterogeneous set of domestic policy instruments, including carbon taxes and various types of regulation, although the linking is more challenging under such circumstances. On this, see “Linking Policies When Tastes Differ: Global Climate Policy in a Heterogeneous World,” a discussion paper by Gilbert Metcalf, Department of Economics, Tufts University, and David Weisbach, University of Chicago Law School, for the Harvard Project on Climate Agreements.
Concerns About Linking
Importantly, trading brought about by unrestricted links between CAT systems will lead to the automatic propagation of certain design elements, including: offset provisions and linkages with other systems; banking and borrowing of allowances across time; and safety-valve provisions. If these provisions, sometimes characterized as cost-containment measures, are present in one of the linked systems, they will automatically be made available to participants in the other system.
In the near-term, some links will be more attractive and easier to establish than others. Given the design-element propagation implications of two-way links between cap-and-trade systems, to facilitate such links it may be necessary to harmonize some design elements. And in some cases, it may be necessary to establish broader international agreements governing aspects of the design of linked cap-and-trade systems beyond mutual recognition of allowances.
An Emerging De Facto International Climate Policy Architecture?
Whereas some two-way links between cap-and-trade systems may thus take more time to establish, in the near-term one-way links between cap-and-trade and credit systems likely will be more attractive and easier to establish. A one-way link with a credit system may offer a cap-and-trade system greater cost savings than a two-way link with another cap-and-trade system. Also, such one-way links can only reduce allowance prices in the cap-and-trade system, giving a government greater control over its system than if it established a two-way link with another cap-and-trade system. The additionality problem is an important concern associated with such links, but it can be managed – to some degree – through the criteria established for awarding or recognizing credits.
Most important, if emerging cap-and-trade systems link with a common credit system, such as the CDM, this will create indirect links among the cap-and-trade systems. Through the indirect links that they create, such one-way linkages can achieve much of the near-term cost savings and risk diversification that direct two-way links among cap-and-trade systems would achieve. And they can do this without requiring the same foundation that likely would be needed to establish direct two-way links, such as harmonization of cost-containment measures. Such linkage may well emerge as part of the de facto post-Kyoto international climate policy architecture, and is fully consistent with the bottom-up, decentralized approach of the Cancun Agreements.
