Market Mechanisms in the Paris Climate Agreement: International Linkage under Article 6.2

The Harvard Project on Climate Agreements hosted a research workshop in Cambridge, Massachusetts, on July 14–15, 2016, the purpose of which was to identify options for elaborating and implementing the Paris Climate Agreement, and to identify policies and institutions that might complement or supplement the United Nations Framework Convention on Climate Change (UNFCCC) process.  We were motivated by our recognition that while the Paris Agreement sets forth an innovative and potentially effective policy architecture for dealing with global climate change, a great deal remains to be done to elaborate the accord, formulate required rules and guidelines, and specify means of implementation.

Participants in the workshop – International Climate Change Policy after Parisincluded twenty-one of the world’s leading researchers focusing on climate-change policy, representing the disciplines of economics, political science, international relations, and legal scholarship. They came from Argentina, Belgium, China, Germany, India, Italy, Norway, the United Kingdom, and the United States.  (A list of workshop participants is here, biographies here, and the agenda here.)

The Harvard Project will next focus on communicating the ideas, insights, and recommendations of workshop participants to climate negotiators and policy makers, in the expectation that they might prove useful in elaborating and implementing the Paris Agreement. Each participant is preparing a brief—based largely on her or his presentation during the workshop. These briefs, together with a workshop summary, will be conveyed to participants in the Twenty-Second Conference of the Parties (COP-22) of the UNFCCC in Marrakech, Morocco in November 2016.  This will be done in meetings with negotiators representing UNFCCC member governments and in a side-event panel at COP-22.

Today I wish to share with readers just one of these draft briefs – namely, my own – on the topic of “International Linkage under Article 6.2 of the Paris Agreement.”

A Key Challenge for Sustained Success of the Paris Agreement

For sustained success of the international climate regime, a key question is whether the Paris Agreement with its Intended Nationally Determined Contributions (INDCs), anchored as they are in domestic political realities, can progressively lead to submissions with sufficient ambition?  Are there ways to enable and facilitate increased ambition over time?

Linkage of regional, national, and sub-national policies can be part of the answer. By “linkage,” I mean connections among policy systems that allow for emission reduction efforts to be redistributed across systems. Such linkage is typically framed as being between two (or more) cap-and-trade systems, but national policies will surely be highly heterogeneous under the Paris climate regime.  Fortunately, research – by Gilbert Metcalf of Tufts University and David Weisbach of the University of Chicago – indicates that linkage between pairings of various types of domestic policy instruments may be feasible.

Linkage and the Paris Agreement

Experience indicates that linkage will bring both merits and concerns in most applications.  To begin with the good news, linkage offers a number of important advantages. First, it offers the possibility of achieving cost savings if marginal abatement costs are heterogeneous across jurisdictions, which they surely are. In addition, linkage can improve the functioning of individual markets by reducing market power, and by reducing price volatility, although we should recognize that price volatility will also be transmitted from one jurisdiction to another by linkage. Finally linkage can allow for the UNFCCC’s important principle of Common but Differentiated Responsibilities (CBDR), but do so without sacrificing cost-effectiveness.

The possibility of linkage also raises concerns, including that there will be distributional impacts within jurisdictions, that is, the creation of both winners and losers. Also, linkage can bring about the automatic propagation from one jurisdiction to another of some design elements, in particular, cost-containment mechanisms, such as banking, borrowing, and price collars. In this and other ways, linkage raises concerns about decreased autonomy.

Linkage under Article 6.2 of the Paris Agreement

It was by no means preordained that the Paris Agreement would allow, let alone encourage, international linkage.  Fortunately, the negotiations which took place in Paris in December, 2015, produced an Agreement that includes in its Article 6.2 the necessary building blocks for linkages to occur.

Under Article 6.2, emissions reductions occurring outside of the geographic jurisdiction of a Party to the Agreement can be counted toward achieving that Party’s Nationally Determined Contribution (NDC) via Internationally Transferred Mitigation Outcomes (ITMOs).  This enables both the formation of “clubs” or other types of coalitions, as well as bottom-up heterogeneous linkage.  Such linkage among Parties to the Agreement would provide for exchanges between compliance entities within the jurisdictions of two different Parties, not simply the government-to-government trading (of Assigned Amounts or AAUs), as was the case with the Kyoto Protocol’s Article 17.

Linkage among Heterogeneous Nationally Determined Contributions

There are three types of heterogeneity which are important in regard to linkage under Article 6.2 of the Paris Agreement. First is heterogeneity among policy instruments. As demonstrated by Metcalf and Weisbach (see above), not only can one cap-and-trade system be linked with another cap-and-trade system, but it is also possible to link a cap-and-trade system with a carbon tax system. In addition, either a cap-and-trade system or a tax system can be linked (via appropriate offsets) with a performance standard in another jurisdiction.  (Linkage with systems employing technology standards are not feasible, however, because such systems are not output-based.)

A second form of heterogeneity that affects linkage and is potentially very important under the Paris Agreement is heterogeneity regarding the level of government action of the relevant jurisdictions. Although the Paris Agreement has as Parties both regional jurisdictions (in the case of the European Union) and national jurisdictions, sub-national jurisdictions are also taking action in some parts of the world. In fact, linkage has already been established between the state of California in the United States and the provinces of Québec and Ontario in Canada.

A third form of relevant heterogeneity is with regards to the NDC targets themselves.  Some are in the form of hard (mass–based) emissions caps, while others are in the form of rate-based emissions caps, either emissions per unit of economic activity, or emissions per unit of output (such as per unit of electricity production). There are also relative mass-based emissions caps in the set of existing NDCs, such as those that are relative to business-as-usual emissions in a specific future year.  Beyond these, there are other parties that have put forward NDCs that do not involve emission caps at all, but rather targets in terms of some other metric, such as the degree of penetration of renewable energy sources.

Combinations of various options under these three forms of heterogeneity yield a considerable variety of types of potential linkages, which may be thought of as the cells of a three-dimensional matrix.  Not all of these cells, however, represent linkages which are feasible, let alone desirable.

The Path Ahead – Key Issues and Questions

There are a substantial number of issues that negotiators will eventually need to address, and likewise, there are a set of questions that researchers (including within the Harvard Project on Climate Agreements) can begin to address now. Among the key issues for negotiators will be the necessity to develop accounting procedures and mechanisms. Also, it will be important to identify means for the ITMOs to be tracked in order to avoid double-counting of emissions reductions. And a broader question is whether and how the UNFCCC Secretariat or some other designated institution will provide any oversight that may be required.

For research, three questions stand out.  First, among pairings from the (3-D matrix) set of instrument–jurisdiction–target combinations that emerge from the three types of heterogeneity identified above, which linkages will actually be feasible?  Second, within this feasible set, are some types of linkages feasible, but not desirable? And third, what accounting treatments and tracking mechanisms will be necessary for these various types of linkages?  Future research will need to focus on these and related questions in order to achieve the potential benefits of Article 6.2 of the Paris Agreement.  Please stay tuned as this work develops.

Misleading Talk about Decoupling CO2 Emissions and Economic Growth

You can call it my pet peeve or even my obsession, but whenever I read about the claimed “decoupling” of CO2 emissions and economic growth, I get annoyed.  Webster’s Dictionary defines decoupling as “eliminating the interrelationship” between two processes.  But the interrelationship between CO2 emissions and economic growth has certainly not been eliminated.

Decoupling is the wrong word and metaphor to describe what has been happening.  When a caboose is decoupled from a train, it stops moving altogether.  A better metaphor, although less linguistically appealing, would be a “slipping clutch.”  The engine continues to transmit power, and as a result the driveshaft continues to rotate, but with less velocity than when the clutch was new.

What Has Been Happening

True enough, the carbon intensities of many economies in the world, particularly those of the industrialized nations, have – for many years – been falling, as those economies have become less energy intensive (less energy use per unit of economic activity – Gross Domestic Product or GDP), and therefore less carbon intensive.  For each dollar of economic activity, CO2 emissions are less than they used to be.  For each unit of economic growth, there is less growth in CO2 emissions than previously.

Furthermore, in some cases, as economies grow, CO2 emissions can actually fall.  First, picture an economy which is growing exclusively in its services sector.  In this case, economic growth might be accompanied by no change in CO2 emissions.  Now picture an economy which is growing in its services sector, while shrinking in its manufacturing sector (sound familiar?).  In this case, economic growth might be accompanied by reduced CO2 emissions.  Now add to this picture the presence of some public policies, such as those that cause the closure of coal-fired electric generation plants, as well as greater dispatch of electricity from natural gas-fired plants.  The result:  economic growth continues, with falling CO2 emissions.  But there has been no decoupling.

Confusion Due to Failure to Employ Appropriate Counterfactual

The problem and the confusion arises from a very common mistake in the popular press and, for that matter, in many casual conversations:  failure to use the right counterfactual for analysis.  The fact that GDP is rising while emissions are falling does not mean that GDP is not affecting emissions.  The appropriate counterfactual for comparison is how much would emissions have fallen had there been no growth in GDP.  Presumably, emissions would have fallen even more.  The excess of emissions in the factual case, compared with the counterfactual case, is the magnitude of emissions growth due to (actually, “associated with”) economic growth.  There has been no elimination of the relationship between the two, although the nature and the magnitude of that relationship has changed.

What Factors Affect CO2 Emissions?

So, why have CO2 emissions been declining in some countries?  Or, more broadly and more to the point, what factors have affected CO2 emissions?  Four stand out (although there are others).

First, energy comes at a cost in all economies, and so economic incentives exist to economize on energy use through technological change.  The energy-intensity of the U.S. economy has gradually fallen – almost monotonically – since early in the twentieth century.

Second, putting aside energy-intensity and focusing on carbon intensity, some technological change has worked against the use of carbon-intensive sources of energy.  The most dramatic example, specific to the United States, has been the combination of horizontal drilling and hydraulic fracturing (fracking), which has caused a significant increase in supply and dramatic fall in the market price of natural gas, which has thereby led to a massive shift of investment and electricity dispatch from coal to natural gas.

Third, in the richer countries of the world, including this one, the process of economic growth has led to changing sectoral composition:  heavy industry to light manufacturing to services.  The deindustrialization of California is a graphic example.  Does the fact that California’s economy has grown while emissions have fallen mean that decoupling has occurred?  Of course not.  And, in the California case, there has also been a fourth factor …

Fourth, public policies have in some jurisdictions of the world (Europe, the United States, and most of the other OECD countries) discouraged carbon intensity.  In the USA, this has happened both through climate policies and other, non-climate policies.  Some non-climate policies, such as EPA’s Mercury Rule, discourage investment, encourage retirement, and discourage dispatch of coal-fired electricity, while other non-climate policies, such as CAFE standards for motor vehicles, bring about greater fuel efficiency of the fleet of cars and trucks over time.  Climate-specific policies have also mattered, such as in California, where the Global Warming Solutions Act of 2006 (AB-32) has brought down emissions through a portfolio of policies, including an economy-wide CO2 cap-and-trade system.

The Bottom Line

So, yes, the carbon intensity of many economies continues to fall – for a variety of reasons, including but by no means limited to public policies.  And, in some cases, the combination of energy price changes, technological change, changes in sectoral composition, and climate and other public policies has meant that emissions have fallen in years when economic growth has continued.  But don’t be fooled.  Economic growth does affect CO2 emissions.  There has been no decoupling; just some (desirable) slipping of the clutch.

Of course, this is not an anti-environment message.  On the contrary, a belief in decoupling per se could lead to a misguided laissez-faire attitude about the path of CO2 emissions.  Being honest and accurate about the links between (desirable) economic growth and (desirable) CO2 emissions reductions puts our focus and emphasis where it ought to be:  finding better ways to have both.

Paris Agreement — A Good Foundation for Meaningful Progress

The Paris Agreement, a truly landmark climate accord, which was gaveled through today, December 12, 2015, at 7:26 pm (Paris time) at the Twenty-First Conference of the Parties (COP-21), checks all the boxes in my five-point scorecard for a potentially effective Paris Agreement, described in my November 17th blog essay, Paris Can Be a Key Step.  The Agreement provides a broad foundation for meaningful progress on climate change, and represents a dramatic departure from the Kyoto Protocol and the past 20 years of climate negotiations.

Essential Background

Anyone who has read this blog over the past several years, or – even more so — my academic writing over the past twenty years on international climate change policy architecture, knows that I have viewed the dichotomous distinction between Annex I and non-Annex I countries as the major stumbling block to progress. That distinction was first introduced in the climate negotiations at COP-1 in Berlin in 1995. That was, in my view, an unfortunate and narrow interpretation of the sound equity principle in the United Nations Framework Convention on Climate Change (UNFCCC, 1992) – “common but differentiated responsibilities and respective capabilities.” It was codified two years later in the Kyoto Protocol.

The Kyoto Protocol, which has been the primary international agreement to reduce the greenhouse-gas emissions that cause global climate change, included mandatory emissions-reduction obligations only for developed countries. Developing countries had no emissions-reduction commitments. The dichotomous distinction between the developed and developing countries in the Kyoto Protocol has made progress on climate change impossible, because growth in emissions since the Protocol came into force in 2005 is entirely in the large developing countries—China, India, Brazil, Korea, South Africa, Mexico, and Indonesia. The big break came at the annual UNFCCC negotiating session in Durban, South Africa in 2011, where a decision was adopted by member countries to “develop [by December 2015, in Paris] a protocol, another legal instrument or an agreed outcome with legal force under the Convention applicable to all Parties.” This “Durban Platform for Enhanced Action” broke with the Kyoto Protocol and signaled a new opening for innovative thinking (which we, at the Harvard Project on Climate Agreements, took to heart).

The Paris Agreement is a Departure from the Past

Today, in Paris, representatives of 195 countries adopted a new hybrid international climate policy architecture that includes: bottom-up elements in the form of “Intended Nationally Determined Contributions” (INDCs), which are national targets and actions that arise from national policies; and top-down elements for oversight, guidance, and coordination. Now, all countries will be involved in taking actions to reduce emissions.

Remarkably, 186 of the 195 members of the UNFCCC submitted INDCs by the end of the Paris talks, representing some 96% of global emissions. Contrast that with the Kyoto Protocol, which now covers countries (Europe and New Zealand) accounting for no more than 14% of global emissions (and 0% of global emissions growth).

This broad scope of participation under the new Paris Agreement is a necessary condition for meaningful action, but, of course, it is not a sufficient condition. Also required is adequate ambition of the individual contributions. But this is only the first step with this new approach. The INDCs will be assessed and revised every five years, with their collective ambition ratcheted up over time. That said, even this initial set of contributions could cut anticipated temperature increases this century to about 3.5 degrees Centigrade, more than the frequently-discussed aspirational goal of limiting temperature increases to 2 degrees C (or the new aspirational target from Paris of 1.5 degrees C), but much less than the 5-6 degrees C increase that would be expected without this action. (An amendment to the Montreal Protocol to address hydrofluorocarbons (HFCs) is likely to shave an addition 0.5 C of warming.)

The problem has not been solved, and it will not be for years to come, but the new approach brought about by the Paris Agreement can be a key step toward reducing the threat of global climate change.

The new climate agreement, despite being path-breaking and the result of what Coral Davenport writing in The New York Times rightly called “an extraordinary effort at international diplomacy,” is only a foundation for moving forward, but it is a sufficiently broad and sensible foundation to make increased ambition over time feasible for the first time.  Whether the Agreement is truly successful, whether this foundation for progress is effectively exploited over the years ahead by the Parties to the Agreement, is something we will know only ten, twenty, or more years from now.

What is key in the Agreement is the following: the centrality of the INDC structure (through which 186 countries representing 96% of global emissions have made submissions); the most balanced transparency requirements ever promulgated; provision for heterogeneous linkage, including international carbon markets (through “internationally transferred mitigation outcomes” – ITMOs); explicit clarification in a decision that agreement on “loss and damage” does not provide a basis for liability of compensation; and 5-year periods for stocktaking and improvement of the INDCs.

The Key Elements of the Paris Agreement

Here are some of the highlights of what stands out to me in the Paris Agreement.

Article 2 of the Agreement reaffirms the goal of limiting the global average temperature increase above the pre-industrial level to 2 degrees C, and adds 1.5 degrees C as something even more aspirational.  In my opinion, these aspirational goals – which come not from science (although endorsed by most scientists) nor economics, and may not even be feasible – are much less important than the critical components of the agreement:  the scope of participation through the INDC structure, and the mechanisms for implementation (see below).

Article 3 makes it clear that the INDC structure is central and universal for all parties, although Article 4 blurs this a bit with references to the circumstances of developing country Parties. But throughout the Agreement, it is abundantly clear that the firewall from the 1995 Berlin Mandate has finally been breached. In addition, five-year periods for the submission of revised INDCs (and global stocktaking of the impact of the Paris Agreement) are included in Article 14.  The first stocktaking review will be in 2018, with the start date for new INDCs set for 2020.

Article 4 importantly describes transparency requirements (domestic monitoring, reporting, and verification).  This is crucial, and represents a striking compromise between the U.S. and Europe, on the one hand, and China and India, on the other hand. All countries must eventually face the same monitoring and reporting requirements, regardless of their status as developed or developing.

Article 6 provides for international policy linkage, and is thereby exceptionally important for the successful exploitation of the foundation provided by the Paris Agreement.  The necessary language for heterogeneous international policy linkage (not only international carbon markets, but international linkage of other national policy instruments) is included. I have written about this key issue many times over the past ten years. It can bring down compliance costs greatly, and thereby facilitate greater ambition over time. (See our paper on this from the Harvard Project on Climate Agreements:  “Facilitating Linkage of Heterogeneous Regional, National, and Sub-National Climate Policies Through a Future International Agreement” By Daniel Bodansky, Seth Hoedl, Gilbert E. Metcalf and Robert N. Stavins, November 2014.)  The Paris Agreement accomplishes this through provision for “internationally transferred mitigation outcomes.” With this provision, we have a new climate policy acronym – ITMOs – about which I suspect I will be writing in the future.

There is considerable discussion of “finance” in Article 9, but the numbers do not appear in the Agreement, only in the accompanying Decision, where item 54 states that by 2025, the Parties will revisit the total quantity of funding, using the current $100 billion target as a “floor.”

Finally, the Agreement’s Article 8 on Loss and Damage was necessary from the point of view of the most vulnerable countries, but the most contentious issue is settled in Decision 52, where the Parties agree that this “does not involve or provide a basis for any liability of compensation.”  That decision was absolutely essential from the perspective of the largest emitters.

Anticipated Impacts of the Paris Agreement

Before I turn to my assessment of the Agreement, I should comment briefly on a topic that seems to be of considerable interest to many people (based on the questions I received from the press during my 10 days in Paris), namely what effect will the Agreement have on business, what signals will it send to the private sector?

My answer is that impacts on businesses will come largely not directly from the Paris Agreement, but from the policy actions that the various Parties undertake domestically in their respective jurisdictions to comply with the Paris Agreement.  I am again referring to the 186 countries which submitted Intended Nationally Determined Contributions – INDCs – under the Agreement.

So, in the case of the United States, for example, those policies that will enable the country to achieve its submitted INDC are: the Clean Power Plan (which will accelerate the shift in many states from coal to natural gas for electricity generation, as well as provide incentives in some states for renewable electricity generation); CAFE (motor vehicle fuel efficiency) standards increasing over time (as already enacted by Congress); appliance efficiency standards moving up over time (as also already enacted by Congress); California’s very aggressive climate policy (AB-32); and the northeast states’ Regional Greenhouse Gas Initiative.

These various policies are credible, and they will send price signals that affect business decisions (but not across the board nor with ideal efficiency, as would a national carbon tax or a national carbon cap-and-trade system). In terms of impacts on specific companies, impacts will continue to vary greatly. But a useful generalization is that a major effect of most climate policies is to raise energy costs, which tends to be good news for producers of energy-consuming durable goods (for example, the Boeing Company) and bad news for consumers of those same energy-consuming durable goods (for example, United Airlines).

An Assessment with my Paris Scorecard

Lastly, here is my November 17th scorecard and my assessment of the five key elements I said would constitute a successful 21st Conference of the Parties:

  1. Include approximately 90% of global emissions in the set of INDCs that are submitted and part of the Paris Agreement (compared with 14% in the current commitment period of the Kyoto Protocol). This was obviously achieved, with total coverage reaching 96% of global emissions.
  1. Establish credible reporting and transparency requirements. This was achieved, through long negotiations between China and India, on the one hand, and Europe and the United States, on the other.
  1. Move forward with finance for climate adaptation (and mitigation) B the famous $100 billion commitment. This was achieved.
  1. Agree to return to negotiations periodically, such as every 5 years, to revisit the ambition and structure of the INDCs. This was achieved.
  1. Put aside unproductive disagreements, such as on so-called “loss and damage,” which appears to rich countries like unlimited liability for bad weather events in developing countries, and the insistence by some parties that the INDCs themselves be binding under international law. This would have required Senate ratification of the Agreement in the United States, which would have meant that the United States would not be a party to the Agreement. There was success on both of these.

Final Words

So, my fundamental assessment of the Paris climate talks is that they were a great success. Unfortunately, as I have said before, some advocates and some members of the press will likely characterize the outcome as a “failure,” because the 2 degree C target has not been achieved immediately.

Let me conclude where I started. The Paris Agreement provides an important new foundation for meaningful progress on climate change, and represents a dramatic departure from the past 20 years of international climate negotiations.  Of course, the problem has not been solved, and it will not be for many years to come. But the new approach brought about by the Paris Agreement can be a key step toward reducing the threat of global climate change. In truth, only time will tell.


As many of you know, over a period of ten days, we (the Harvard Project on Climate Agreements) were hard at work at COP-21 in Paris. I made a dozen presentations and we held bilateral meetings on a daily basis with national negotiating teams and and others. You will find videos, photos, and numerous stories about our activities in Paris at our Tumblr page. Thanks are due to the entire team who were with me in Paris – Robert Stowe, executive director, Jason Chapman, program manager, and Doug Gavel, director of media relations — as well as Bryan Galcik, communications coordinator, back in Cambridge.