09/12/2009 05:12 am ET | Updated May 25, 2011

Cap-and-Trade: A Fly in the Ointment?

For more than two decades, environmental law and regulation was dominated by command-and-control approaches -- typically either mandated pollution control technologies or inflexible discharge standards on a smokestack-by-smokestack basis. But in the 1980s, policy makers increasingly explored market-based environmental policy instruments, mechanisms that provide economic incentives for firms and individuals to carry out cost-effective pollution control. Cap-and-trade systems, in which emission permits or allowances can be traded among potential polluters, continue today to be at the center of this action.

Most recently, this has been in the context of deliberations regarding possible U.S. actions to reduced carbon dioxide and other greenhouse gas emissions linked with global climate change, as in HR 2454, the Waxman-Markey bill approved by the U.S. House of Representatives, as well as in proposals developing in the Senate. (I have written a number of blog posts on this topic. If you're interested, please see: "Opportunity for a Defining Moment" (February 6, 2009); "The Wonderful Politics of Cap-and-Trade: A Closer Look at Waxman-Markey" (May 27, 2009); "Worried About International Competitiveness? Another Look at the Waxman-Markey Cap-and-Trade Proposal" (June 18, 2009); "National Climate Change Policy: A Quick Look Back at Waxman-Markey and the Road Ahead" (June 29, 2009). For a more detailed account, see my Hamilton Project paper, A U.S. Cap-and-Trade System to Address Global Climate Change.)

But the transition from command-and-control regulation to market-based policy instruments has not always been easy. Sometimes policy can outrun basic understanding, and the claims made for the cost-effectiveness of cap-and-trade systems can exceed what can be reasonably anticipated. Among the factors that can adversely affect the performance of such systems are transaction costs.

In general, transaction costs -- those costs that arise from the exchange, not the production, of goods and services -- are ubiquitous in market economies. They can arise from any exchange: after all, parties to transactions must find one another, communicate, and exchange information. It may be necessary to inspect and sometimes even measure goods to be transferred, draw up contracts, consult with lawyers or other experts, and transfer title.

In cap-and-trade markets, there are three potential sources of transaction costs. The first source, searching and information-collection, arises because it can take time for a potential buyer of a discharge permit to find a seller, though -- for a fee -- brokers can facilitate the process. Although less obvious, a second source of transaction costs -- bargaining and deciding -- is potentially as important. A firm entering into negotiations incurs real resource costs, including time and/or fees for brokerage, legal, and insurance services. Likewise, the third source -- monitoring and enforcing -- can be significant, although these costs are typically borne by the responsible governmental authority and not by trading partners.

The cost savings that may be realized through cap-and-trade systems depend upon active trading. But transaction costs are an impediment to trading, and such impediments thereby can limit savings. So, transaction costs reduce the overall economic benefits of allowance trading, partly by absorbing resources directly and partly by suppressing exchanges that otherwise would have been mutually (indeed socially) beneficial. But when transaction costs can be kept to a minimum, high levels of trading -- and significant cost savings - are the result.

Since David Montgomery's path-breaking work in 1972, economists have asserted that the post-trading allocation of control responsibility among sources and hence the aggregate costs of control are independent from the initial permit allocation. This is an extremely important political property, but does this still hold in the presence of transaction costs? This is a question I investigated in an article titled, "Transaction Costs and Tradable Permits," which was published in the Journal of Environmental Economics and Management in 1995 (and which the publisher lists as one of the ten most cited articles in the journal's history, going back to 1974).

The answer to this question is: "it depends." If incremental transaction costs are independent of the size of individual transactions, the initial allocation of permits has no effect on the post-trading allocation of control responsibility and aggregate control costs. But if incremental transaction costs decrease with the size of individual trades, then the initial allocation will affect the post-trading outcome.

This is of great political importance, because it means that in the presence of transaction costs, the initial distribution of permits can matter not only in terms of distributional equity, but in terms of cost-effectiveness or efficiency. This can reduce the discretion of the Congress (or other legislature or agency) to distribute allowances as they please (in order to generate a constituency of support for the program), and may thereby reduce the political attractiveness and feasibility of a cap-and-trade system.

Empirical evidence, however, indicates that transaction costs have been minimal, indeed trivial, in enacted and implemented cap-and-trade systems, including the U.S. EPA's leaded-gasoline phasedown in the 1980s, and the well-known SO2 allowance trading system, enacted as part of the Clean Air Act amendments of 1990.

That's good news, surely. But nevertheless, going forward, choices between conventional, command-and-control environmental policies and market-based instruments should reflect the imperfect world in which these instruments are applied. Such choices are not simple, because no policy panacea exists.

On the one hand, even if transaction costs prevent significant levels of trade from occurring, aggregate costs of control will most likely be less than those of a conventional command-and-control approach. A trading system with no trading taking place will likely be less costly than a technology standard (because the trading system provides flexibility to firms regarding their chosen means of control) and no more costly than a uniform performance standard.

But the existence of transaction costs may make the choice between conventional approaches and cap-and-trade more difficult because of the ambiguities that are introduced. With transaction costs -- as with other departures from frictionless markets -- greater attention is required to the details of designing specific systems. This is the way to lessen the risk of over-selling such policy ideas and ultimately creating systems that stand the best chance of being implemented successfully.