AB 32, RGGI, and Climate Change: The National Context of State Policies for a Global Commons Problem

Why should anyone be interested in the national context of a state policy?  In the case of California’s Global Warming Solutions Act (AB 32), the answer flows directly from the very nature of the problem — global climate change, the ultimate global commons problem.  Greenhouse gases (GHGs) uniformly mix in the atmosphere.  Therefore, any jurisdiction taking action — whether a nation, a state, or a city — will incur the costs of its actions, but the benefits of its actions (reduced risk of climate change damages) will be distributed globally.  Hence, for virtually any jurisdiction, the benefits it reaps from its climate‑policy actions will be less than the cost it incurs.  This is despite the fact that the global benefits of action may well be greater — possibly much greater — than global costs.

This presents a classic free-rider problem, in which it is in the interest of each jurisdiction to wait for others to take action, and benefit from their actions (that is, free-ride).  This is the fundamental reason why the highest levels of effective government should be involved, that is, sovereign states (nations).  And this is why international, if not global, cooperation is essential. [See the extensive work in this area of the Harvard Project on International Climate Agreements.]

Despite this fundamental reality, there can still be a valuable role for sub-national climate policies.  Indeed, my purpose in this essay is to explore the potential for such state and regional policies — both in the presence of Federal climate policy and in the absence of such policy.  I begin by describing the national climate policy context, and then turn to sub-national policies, such as California’s AB 32 and the Regional Greenhouse Gas Initiative (RGGI) in the northeast.  My focus is on how these sub-national 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.  I also examine the role that could be played by sub-national policies in the absence of a meaningful Federal policy, with the conclusion that — like it or not — we may find that Sacramento comes to take the place of Washington as the center of national climate policy.

The (Long-Term) National Context:  Carbon-Pricing

I need not tell readers of this blog that virtually all economists and most other policy analysts favor a national carbon‑pricing policy (whether carbon tax or cap-and-trade) as the core of any meaningful climate policy action in the United States.  Why is this approach so overwhelmingly favored by the analytical community?

First, no other feasible approach can provide truly meaningful emissions reductions (such as an 80% cut in national CO2 emissions by mid-century).  Second, it is the least costly approach in the short term, because abatement costs are exceptionally heterogeneous across sources.  Only carbon-pricing provides strong incentives that push all sources to control at the same marginal abatement cost, thereby achieving a given aggregate target at the lowest possible cost.  Third, it is the least costly approach in the long term, because it provides incentives for carbon-friendly technological change, which brings down costs over time.  Fourth, although carbon pricing is not sufficient on its own (because of other market failures that reduce the impact of price signals — more about this below), it is a necessary component of a sensible climate policy, because of factors 1 through 3, above.  [I’ve written about carbon-pricing in many previous blog posts, including on June 23, 2010, “The Real Options for U.S. Climate Policy.”]

But carbon-pricing is a hot-button political issue.  This is primarily because it makes the costs of the policy transparent, unlike conventional policy instruments, such as performance and technology standards, which tend to hide costs.  Carbon-pricing is easily associated with the dreaded T-word.  Indeed, in Washington, cap-and-trade has been successfully demonized as “cap-and-tax.” As a result, the political reality now appears to be that a national, economy-wide carbon-pricing policy is unlikely to be enacted before 2013.  Does this mean that there will be no Federal climate policy in the meantime?  No, not at all.

The (Short-Term) National Context:  Federal Regulations on the Way or Already in Place

Regulations of various kinds may soon be forthcoming — and in some cases, will definitely be forthcoming — as a result of the U.S. Supreme Court decision in Massachusetts v. EPA and the Obama administration’s subsequent “endangerment finding” that emissions of carbon dioxide and other greenhouse gases endanger public health and welfare.  This triggered mobile source standards earlier this year, the promulgation of which identified carbon dioxide as a pollutant under the Clean Air Act, thereby initiating a process of using the Clean Air Act for stationary sources as well.

Those new standards are scheduled to begin on January 2, 2011, with or without the so‑called “tailoring rule” that would exempt smaller sources.  Among the possible types of regulation that could be forthcoming for stationary sources under the Clean Air Act are:  new source performance standards; performance standards for existing sources (Section 111(d)); and New Source Review with Best Available Control Technology standards under Section 165.

The merits that have been suggested of such regulatory action are that it would be effective in some sectors, and that the threat of such regulation will spur Congress to take action with a more sensible approach, namely, an economy-wide cap‑and‑trade system.  However, regulatory action on carbon dioxide under the Clean Air Act will accomplish relatively little and do so at relatively high cost, compared with carbon pricing.  Also, it is not clear that this threat will force the hand of Congress; it clearly has not yet done so.  Indeed, it is reasonable to ask whether this is a credible threat, or will instead turn out to be counter‑productive (when stories about the implementation of inflexible, high‑cost regulatory approaches lend ammunition to the staunchest opponents of climate policy).

It’s also possible that air pollution policies for non‑greenhouse gas pollutants, the emissions of some of which are highly correlated with CO2 emissions, may play an important role.  For example, three‑pollutant legislation focused on SOx, NOx, and mercury could have profound impacts on the construction and operation of coal‑fired electricity plants, without any direct CO2 requirements.  Without any new legislation, a set of rules which could have significant impacts on coal-fired power plants are now making their way through the regulatory process — including regulations affecting ambient ozone, SO2/NO2, particulates, ash, hazardous air pollutants (mercury), and effluent water.

There is also the possibility of new energy policies (not targeted exclusively at climate change) having significant impacts on CO2 emissions.  The possible components of such an approach that would be relevant in the context of climate change include:  a national renewable electricity standard; Federal financing for clean energy projects: energy efficiency measures (building, appliance, and industrial efficiency standards; home retrofit subsidies; and smart grid standards, subsidies, and dynamic pricing policies); and new Federal electricity‑transmission siting authority.

Even without action by the Congress or by the Administration, legal action on climate policy is likely to take place within the judicial realm.  Public nuisance litigation will no doubt continue, with a diverse set of lawsuits being filed across the country in pursuit of injunctive relief and/or damages.  Due to recent court decisions, the pace, the promise, and the problems of this approach remain uncertain.

Beyond the well‑defined area of public nuisance litigation, other interventions which are intended to block permits for new fossil energy investments, including both power plants and transmission lines will continue.  Some of these interventions will be of the conventional NIMBY character, but others will no doubt be more strategic.

But with political stalemate in Washington on carbon-pricing or national climate policy, attention is inevitably turning to regional, state, and even local policies intended to address climate change.

Sub-National Climate Policies

The Regional Greenhouse Gas Initiative (RGGI) in the Northeast has created a cap‑and‑trade system among electricity generators.  More striking, California’s Global Warming Solutions Act (Assembly Bill 32, or AB 32) will likely lead to the creation of a very ambitious set of climate initiatives, including a statewide cap‑and‑trade system (unless it’s stopped by ballot initiative — Proposition 23 — or a new Governor, depending on the outcome of the November 2010 elections).  The California system is likely to be linked with systems in other states and Canadian provinces under the Western Climate Initiative.  Currently, more than half of the 50 states are contemplating, developing, or implementing climate policies.

In the presence of a Federal policy, will such state efforts achieve their objectives?  Will the efforts be cost-effective?  The answer is that the interactions of state policies with Federal policy can be problematic, benign, or positive, depending upon their relative scope and stringency, and depending upon the specific policy instruments used.  This is the topic of a paper which Professor Lawrence Goulder (Stanford University) and I have written, “Interactions Between State and Federal Climate Change Policies” (National Bureau of Economic Research Working Paper 16123, June 2010).

Problematic Interactions

Let’s start with the case of a Federal policy which limits emission quantities (as with cap-and-trade) or uses nationwide averaging of performance (as with some proposals for a national renewable portfolio standard).  In this case, emission reductions accomplished by a “green state” with a more stringent policy than the Federal policy — for example, AB 32 combined with Waxman-Markey/H.R. 2454 — will reduce pressure on other states, thereby freeing, indeed encouraging (through lower allowance prices) emission increases in the other states.  The result would be 100% leakage, no gain in environmental protection from the green state’s added activity, and a national loss of cost-effectiveness.

Potential examples of this — depending upon the details of the regulations — include: first, AB 32 cap-and-trade combined with Federal cap-and-trade (H.R. 2454) or combined with some U.S. Clean Air Act performance standards; second, state limits on GHGs/mile combined with Federal CAFE standards; and third, state renewable fuels standards combined with a Federal RFS, or state renewable portfolio standards combined with a Federal RPS.  A partial solution would be for these Federal programs to allow states to opt out of the Federal policy if they had an equally or more stringent state policy.  Such a partial solution would not, however, be cost-effective.

Benign Interactions

One example of benign interactions of state and Federal climate policy is the case of the Regional Greenhouse Gas Initiative (RGGI) in the northeast.  In this case, the state policies are less stringent than an assumed Federal policy (such as H.R. 2454).  The result is that the state policies become non-binding and hence largely irrelevant.

A second example — that warms the hearts of economists, but appears to be politically irrelevant for the time being — is the case of a Federal policy that sets price, not quantity, i.e., a carbon tax, or a binding safety-valve or price collar in a cap-and-trade system.  In this case, more stringent actions in green states do not lead to offsetting emissions in other states induced by a changing carbon price.  It should be noted, however, that there will be different marginal abatement costs across states, and so aggregate reductions would not be achieved cost-effectively.

Positive Interactions

Three scenarios suggest the possibility of positive interactions of state and Federal climate policies.  First, states can — in principle — address market failures not addressed by a Federal carbon-pricing policy.  A prime example is the principal‑agent problem of insufficient energy‑efficiency investments in renter‑occupied properties, even in the face of high energy prices.  This is a problem that is best addressed at the state or even local level, such as through building codes and zoning.

Second, state and regional authorities frequently argue that states can serve as valuable “laboratories” for policy design, and thereby provide useful information for the development of Federal policy.  However, it is reasonable to ask whether state authorities will allow their “laboratory” to be closed after the experiment has been completed, the information delivered, and a Federal policy put in place.  Pronouncements from some state leaders should cause concern in this regard.

Third, states can create pressure for more stringent Federal policies.  A timely example is provided by California’s Pavley I motor-vehicle fuel-efficiency standards and the subsequent change in Federal CAFE requirements.  There is historical validation of this effect, with California repeatedly having increased the stringency of its local air pollution standards, followed by parallel Federal action under the Clean Air Act.  This linkage is desirable if the previous Federal policy is insufficiently stringent, but whether that is the case is an empirical question.

Thus, in the presence of Federal climate policy, interactions with sub-national policies can be problematic, benign, or positive, depending upon the relative scope and stringency of the sub-national and national policies, as well as the particular policy instruments employed at both levels. [For a more rigorous derivation of the findings above, as well as an examination of a larger set of examples, please see my paper with Stanford Professor Lawrence Goulder, referenced above.]

But comprehensive Federal carbon-pricing policy appears to be delayed until 2013, at the earliest.  And it is possible that pending Federal regulatory action under the Clean Air Act will be curtailed or significantly delayed either by the new Congress or by litigation.  Therefore, it is important to consider the role of state and regional climate policies in the absence of Federal action.

Sub-National Climate Policies in the Absence of Federal Action

In brief, in the absence of meaningful Federal action, sub‑national climate policies could well become the core of national action.  Problems will no doubt arise, including legal obstacles such as possible Federal preemption or litigation associated with the so‑called Dormant Commerce Clause.

Also, even a large portfolio of state and regional policies will not be comprehensive of the entire nation, that is, not truly national in scope (for a quick approximation of likely coverage, check out a recent map of blue states and red states).

And even if the state and regional policies were nationally comprehensive, there would be different policies of different stringency in different parts of the country, and so carbon shadow‑prices would by no means be equivalent, meaning that the overall policy objectives would be achieved at excessive social cost.

Is there a solution (if only a partial one)?  Yes.  If the primary policy instrument employed in the state and regional policies is cap-and-trade, then the respective carbon markets can be linked.  Such linkage occurs through bilateral recognition of allowances, which results in reduced costs, reduced price volatility, reduced leakage, and reduced market power.  Good news all around.

Such bottom‑up linkage of state and regional cap‑and‑trade systems could be an important part or perhaps even the core of future of U.S. climate policy, at least until there is meaningful action at the Federal level.  In the meantime, it is at least conceivable — and perhaps likely — that linkage of state‑level cap‑and‑trade systems will become the (interim) de facto national climate policy architecture.

In this way, Sacramento would take the place of Washington as the center of national climate policy deliberations and action.  No doubt, this possibility will please some, and frighten others.


P.S.  For those of you interested in the topic of this blog post, you may also find of particular interest a conference organized by the University of California, taking place in Sacramento on October 4th, “California’s Climate Change Policy:  The Economic and Environmental Impacts of AB 32.”  You can learn more about it by clicking on this link.


Opportunities and Ironies: Climate Policy in Tokyo, Seoul, Brussels, and Washington

As I write this, I’m on board a flight from Seoul, South Korea, to San Francisco, California, on my way home to Boston, having spent the week of Harvard spring break meeting with senior government officials, academics, and leaders of civil society in Tokyo and Seoul on behalf of the Harvard Project on International Climate Agreements.  Reflecting on these meetings in Asia and recalling meetings I’ve previously had in Brussels and Washington, some important opportunities and ironies about national and international climate policy come to mind.


The 15th Conference of the Parties (COP-15) of the United Nations Framework Convention on Climate Change (UNFCCC), which met in Copenhagen, Denmark, in December, 2009, produced two significant outcomes.  The key substantive outcome, of course, was the Copenhagen Accord, about which I’ve written in detail in a previous blog post.  The key institutional outcome was speculation that the UNFCCC may not be the best venue going forward for productive negotiations on climate change.   (This is also a topic about which I’ve recently written at this blog.)

These dual outcomes of the Copenhagen conference point to the special importance of two key nations in international climate policy developments this year.  I’m not referring to China and the United States (despite the fact that they are, of course, the world’s two leading emitters of carbon dioxide).  Rather, I am referring to Korea and Mexico.  Why?

First, these two nations are unique in being both long-time members (Korea since 1996, Mexico since 1994) of the Organization of Economic Cooperation and Development (OECD) and members of the group of non-Annex I countries under the Kyoto Protocol, which have no direct commitments under that international agreement.  The OECD comes as close as anything to defining the set of industrialized nations of the developed world.  Thus, Korea and Mexico have their feet planted firmly both in the developed world and the developing world (a fact that is readily apparent on even brief visits to these nations).  This gives Korea and Mexico remarkable credibility with the two key blocks in international climate negotiations.  That, on its own, would be of considerable importance, but there is another reality that makes this of even greater significance (and opportunity) in this year of 2010.

Coming out of Copenhagen, many participants in the international climate negotiations (as well as informed observers), noted that the UNFCCC has real limitations as the sole venue for future climate negotiations:  too many countries – 192, excessively stringent requirements for agreement – unanimity, and a distinct tendency to polarize debates between developed and developing countries.  Two other, potentially supplementary venues stand out as promising:  the Major Economies Forum (MEF) and the G20.

The MEF, which has hosted productive discussions among 17 key countries and regions that together account for nearly 90 percent of global carbon dioxide (CO2) emissions, may be somewhat limited by the fact that is was created by and is chaired by the United States, a nation with constrained credibility on climate issues among some countries, particularly in the developing world.  The G20, which brings together twenty of the world’s largest economies, focuses on economic as well as other global issues and consists of almost the same set of nations as the MEF, likewise accounting for about 90 percent of global emissions.  The G20 could thus be an exceptionally promising supplementary venue for meaningful and realistic climate discussions.  And in November of this year, the G20 will be hosted by Korea, when it convenes in Seoul.  This gives the Korean government a special role in setting the agenda for the discussions and presiding at the sessions.

The G20 meetings in Seoul will come just two weeks before the Sixteenth Conference of the Parties of the UNFCCC, which will take place in Cancún, Mexico.  Thus, the Mexican government is also in a key position this year, because it will hold the Presidency of COP-16.

Add to this the fact that both Korea and Mexico have been particularly creative in their domestic climate policy initiatives and international proposals over the past year.   Harvard Kennedy School Professor Jeffrey Frankel notes at his blog — Views on the Economy and the World — that Korea and Mexico were particularly ambitious with their submissions to the Copenhagen Accord, when comparing the submissions of all countries in terms of 2020 emissions targets relative to business-as-usual, controlling for per capita income.

Together, Korea and Mexico, share credibility in the developing and developed worlds, and likewise share unique international legitimacy as the hosts and presidents of the G20 and COP-16 in 2010.  This is why these two countries have a remarkable opportunity this year to provide leadership of the international community, and make real progress on negotiations to address the threat of global climate change.  Those are the opportunities.   Now, let me turn to the ironies that have come to the fore.


More than a decade ago, it was the United States, as the leader of the so-called “Umbrella Group,” that successfully fought for the inclusion in the Kyoto Protocol – over the objections of the European Union – of three “flexibility mechanisms” to bring down the costs of meeting the Protocol’s objectives:  joint implementation (Article 4), a global emissions reduction credit system, the Clean Development Mechanism (the CDM, Article 12), and emissions trading among countries (Article 17).  Ironically, once the George W. Bush administration officially pulled the United States out of the Kyoto Protocol process, it was the European Union that implemented the world’s first CO2 emissions trading program, the European Union Emission Trading Scheme (EU ETS).

Beyond this, the United States was a pioneer with the use of national cap-and-trade systems, including lead trading in the 1980s and the SO2 allowance trading program beginning in 1995 under the Clean Air Act Amendments of 1990.  In addition, despite its lack of ratification of the Kyoto Protocol, the U.S. government very early on began to give serious consideration to the development of an economy-wide cap-and-trade system for CO2 with the McCain-Lieberman legislation in the U.S. Senate (followed later by the Lieberman-Warner bill).  More recently, of course, the U.S. House of Representatives passed the Waxman-Markey bill in June of 2009, including a significant economy-wide cap-and-trade system.

Over the past nine months, however, the very phrase, “cap-and-trade,” has evolved from being politically correct in Washington to nothing less than politically anathema.  (How and why this happened is a topic for a future essay at this blog.)  The great irony is that just when cap-and-trade has been under such vociferous attack in Washington, countries throughout the world are embracing this instrument, recognizing its great potential to address climate change cost-effectively and equitably.

In addition to the EU ETS, already in force, Australia is primed to put its cap-and-trade system in place, as is New Zealand.  And just a few days before I arrived in Tokyo, the Japanese cabinet announced that the government will move forward with a cap-and-trade system (in contrast with Japan’s previously proposed sectoral approach).  And, not to be outdone, Korea is considering the use of cap-and-trade as an element of its own domestic climate policy.

This irony is striking.  Of course, it could be reduced or eliminated if Senators Kerry, Graham, and Lieberman can use their much-anticipated new climate proposal to pull victory from the jaws of anticipated defeat.   Only time will tell.


Approaching Copenhagen with a Portfolio of Domestic Commitments

As we approach the beginning of the Fifteenth Conference of the Parties of the United Nations Framework Convention on Climate Change (UNFCCC) in Copenhagen in December, international negotiations are focused on developing a climate policy framework for the post-2012 period, when the Kyoto Protocol’s first commitment period will have ended.  In addition to negotiations under the UNFCCC, other intergovernmental outlets, including the G8(+5) and the Major Economies Forum, are trying to reach common ground among the world’s major emitters of greenhouse gases.  To date, these efforts have not produced a politically, economically, and environmentally viable structure for a future climate agreement.

In the Harvard Project on International Climate Agreements (a global effort which now includes 35 research initiatives in Australia, China, Europe, India, Japan, and the United States), we continue to investigate promising post-2012 international policy architectures, as part of our on-going effort to help the countries of the world identify the key design elements of a post-2012 architecture that is scientifically sound, economically rational, and politically pragmatic.

One approach we have recently examined is a “portfolio of domestic commitments,” an approach which could be effective, but more flexible and politically palatable than other international arrangements.  Under such a scheme, nations would agree to honor commitments to greenhouse gas emission reductions laid out in their own domestic laws and regulations.  A portfolio of commitments might emerge from a global meeting such as the UNFCCC Conference of the Parties, or a smaller number of major economies could negotiate an agreement among themselves, and then invite other countries to join.

Despite the obvious differences between such a system and the conventional “targets and time tables” approach embodied in the Kyoto Protocol, negotiators should not dismiss this new approach out of hand.  There are several ways to construct a portfolio of domestic commitments, and negotiators have numerous levers available to tailor an agreement to meet their political, economic, and environmental goals.  In a recent Harvard Project Viewpoint, I outlined some basic features of a portfolio approach, highlighted a few major issues and concerns, and discussed the potential feasibility of this approach.

The Portfolio of Domestic Commitments Approach

The core of a portfolio of domestic commitments is agreement among a set of member countries to conform to the climate change mitigation requirements specified by their respective domestic laws, regulations, and official planning documents (the last being domestically binding in centrally planned economies).  The portfolio approach gives member countries free rein to dictate the precise form their domestic commitments will take, whether those be greenhouse gas cap-and-trade systems, carbon taxes, intensity targets, performance or technology standards, or other instruments.  A portfolio agreement should be highly credible, given that it is grounded in domestic commitments, binding in and enforceable by law previously made by the very governments signing on to the international agreement.

Domestic commitments might take the form of specified greenhouse gas emission targets or the form of particular actions that could be taken to reduce emissions, both envisioned in the Bali Action Plan as “nationally-appropriate mitigation actions” (NAMAs).  A target-based approach has the advantage of being transparent and relatively simple to aggregate across countries to reach a global target.  On the other hand, action-oriented goals can be more concrete and may be easier for many governments to implement in the short term.  There is no reason why both targets and actions could not be pursued simultaneously.  Coexistence of multiple approaches is not uncommon in environmental policy.

Ongoing commitments for several years into the future are necessary to stabilize and eventually reduce atmospheric greenhouse gas concentrations to combat climate change.  Under a portfolio approach, these domestic commitments could be represented in a table of national schedules attached to an agreement.  Australia has proposed a model agreement that includes such schedules. The schedules would signal a continuing commitment to the international community, and their inclusion in an international agreement would provide a disincentive for member nations to deviate from them in the future.

Countries would not be limited to acting unilaterally to meet their domestic commitments.  They could choose to submit joint goals or targets — for example, on a regional level — or link with other countries through a multinational carbon trading regime to reduce costs.  (Such linkage is the subject of another Harvard Project paper — by Judson Jaffe and myself.)  The portfolio approach would not be a bar to international cooperation.

A primary consideration for a portfolio agreement is the well-established principle of “common but differentiated responsibilities.”  This principle acknowledges that responsibility is shared for solving the climate change challenge, but suggests that historical differences in contribution to the problem and economic and technical disparities be reflected in varying national commitments.  A portfolio of domestic commitments may be particularly well-suited to implement this principle because it allows for countries to make commitments along a continuum of stringency, rather than dividing nations into two groups as did the Kyoto Protocol.  The placement of each country upon the continuum would depend on an array of political, economic, and environmental concerns.  (On this, see recent Harvard Project papers by Jeffrey Frankel and Valentina Bosetti, and by Sheila Olmstead and myself.)

Key Issues for Negotiators

Negotiators will inevitably need to tackle a number of key issues in crafting a portfolio agreement, three of which we highlight here.  The first is the extent to which domestic commitments could be relaxed in later years to reflect changed circumstances.  The second is the formal status such an agreement would have under international law.  Third is the necessity to monitor conformance to domestic commitments.

Rigidity of Commitments

One approach would be for a portfolio agreement to log domestic commitments and allow countries to relax those commitments in response to changes in political or economic climate or advances in the understanding of the threat of climate change.  In essence, such an agreement would function as a depository for current domestic legislation, serving the dual roles of information-gathering and diplomatic recognition of shared commitment to the climate problem.  It is difficult to imagine countries registering objections to such an agreement, given that they would not be binding themselves to future commitments.

For precisely this reason, however, climate negotiators may wish to stay the hand of future governments by barring relaxation or abandonment of preexisting climate commitments.  In other words, the agreement could set minimum commitments on a country-specific basis.  Amendments would be allowed only if they maintained or strengthened domestic commitments to climate change mitigation.  Such a precommitment strategy is not generally included in domestic legislation or plans, and it is likely to require careful wording and additional domestic legislation to become effective in some countries.

There is surely the possibility of domestic commitments being ignored by future leaders, but note that this concern is not unique to the portfolio approach.  All climate policy architectures — indeed, all international agreements — face this problem, and the question is whether the precommitment challenge is greater under this approach than it would be under others.  One possible compromise position would be to allow revision of domestic commitments, but only at specified intervals, in order to account for dramatic shifts in economic or environmental situations and expectations.

Type of Legal Instrument

Another key issue is the official legal status of a portfolio of domestic commitments.  There are a number of possible structures for such an agreement, each with different implications under international law.  A treaty is the most formal option and would be the most binding on participating nations.  Treaty law is relatively well-developed, as compared with the law governing other international instruments, and the law of treaties provides a framework for enforcement and dispute resolution.  But treaties are difficult to craft and face the perils of national ratification.

Outside of a treaty, there are various other instruments of international law that could be used in the portfolio approach.  For example, in the United States, congressional-executive and sole-executive agreements can be entered into by the President and do not require the approval of two-thirds of the Senate, as do treaties.  (See, for example, Nigel Purvis’s work on executive agreements.)   Other “soft law” instruments, such as explicitly nonbinding agreements, political declarations, and U.N. declarations, are fallback options which merit consideration for implementing a portfolio approach.  Ultimately, negotiators will choose the best instrument, based on how open countries are to the agreement and what obligations the agreement imposes.

Monitoring and MRV

Throughout the industrialized countries — and increasingly in the emerging economies — domestic environmental regulations include internal mechanisms for monitoring and enforcement.  A portfolio agreement could rely on countries to be prompted by international pressure to enforce their commitments, or an agreement could take a more active role.  The agreement could, for example, put in place an international monitoring body, license domestic entities in each country to monitor national commitments, or suggest model codes for enforcement.  International assistance may be necessary to aid countries lagging in technical or administrative capacity to monitor greenhouse gas emissions and enforce domestic policies.  More broadly, the agreement would need to define—to the extent possible—uniform measurement, reporting, and verification (MRV) procedures and assure that all countries could implement these procedures.

Feasibility of a Portfolio of Domestic Commitments

A portfolio of domestic commitments has several advantages as the foundation of a future international climate policy architecture.  The agreement could be flexible enough to allow countries to implement the mitigation instruments of their choice and link those instruments with domestic instruments in other nations if they so chose.  It could also allow for countries to accede at various times, thus giving them adequate time to prepare to participate.  (See David Victor’s Harvard Project paper on climate accession deals.)   This approach could also be an ideal vehicle for implementing the principle of common but differentiated responsibilities, since member countries would not need to be lumped together into rigid tiers of commitment (as they are under the dichotomous Annex I approach of the Kyoto Protocol).

Perhaps most crucial is the political feasibility of the portfolio approach.  In recent months, several major economies have expressed willingness to consider a climate policy architecture along these lines, including Australia, India, and the United States.  For this reason alone, the portfolio approach merits serious consideration, despite the significant hurdles to negotiating an effective portfolio agreement.

The concerns regarding this approach to a future global climate policy architecture are significant, but so are its potential advantages.  In general, there are real challenges to developing any post-2012 international climate policy architecture that is scientifically sound, economically rational, and politically pragmatic.  The challenges facing this approach are no greater – and may be less – than those facing other means of addressing the threat of global climate change.