Returning to Paris: The Next U.S. “NDC”

By Susan Biniaz*,

A new Administration will invariably seek to restore U.S. leadership on climate change through a wide range of domestic and international initiatives.  These will include rejoining the 2015 Paris Agreement, from which the United States is set to exit on November 4th of this year.  While rejoining Paris per se will be straightforward, designing the next U.S. “nationally determined contribution” (NDC) is likely to involve a careful balancing of objectives.  This paper looks at those objectives and considers potential options.

How Would a New Administration Rejoin the Paris Agreement?

The United States could readily rejoin the Paris Agreement:

  • As a matter of international law, the Agreement provides that, when a State joins the Agreement after it has already entered into force (which happened in late 2016), it becomes a Party thirty days later. Other Parties would not have any ability to block or otherwise condition the United States’ return.

  • As a matter of domestic law, just as in 2016 when the United States submitted its instrument of acceptance for the first time, the President would have ample authority to join the Agreement. It could even happen on day one of the Administration.

What about the U.S. NDC?

While joining Paris itself would be straightforward, crafting the U.S. NDC — to reflect its greenhouse gas emissions target and possibly other mitigation actions — would likely be more challenging.

NDCs under the Paris Agreement are not legally binding.  However, a Party is legally required to maintain one, i.e., have one in place, at all times.  When the United States joined the Agreement in 2016, the emissions target reflected in the U.S. NDC was a 26-28% reduction in greenhouse gas emissions below 2005 levels in 2025.  (Parties to Paris had a mixture of 2025 and 2030 targets.)

The decision accompanying adoption of the Paris Agreement made a request of Parties with respect to 2020:  those with 2025 targets were requested to submit their next targets, and those with 2030 targets were requested to either update or recommunicate their targets.

The United States will technically still be a Party to Paris through most of 2020; however, no one expects that it will submit a follow-on target; in any event, its withdrawal in late 2020 will extinguish whatever NDC the United States had previously submitted.

Thus, when the United States returns to the Paris Agreement, it will also need to communicate an NDC.  The Agreement reflects an expectation (although not a requirement) that the NDC should reflect an economy-wide absolute reduction target. The contours of the target, including its scope, stringency, base year, and target year, will be up to the United States to decide.

In contrast to signing up for the Agreement itself, the development of an NDC is likely to involve the consideration and balancing of various objectives.

What Are the Potential U.S. Objectives?

A new Administration is likely to have several objectives, some of which are easier to reconcile than others:

  • One likely objective will be immediacy, i.e., there will be a natural, and understandable, inclination to want to send a positive signal on climate change by rejoining the Agreement right away.

  • A second likely objective will be climate ambition, i.e., a target of a sufficiently ambitious nature to meaningfully address the climate challenge and demonstrate (both domestically and to the world) that the new Administration takes climate change seriously, in contrast to the Trump Administration.

  • A third likely objective will be credibility,in the sense of taking on a target that the United States can realistically achieve. The United States will have undoubtedly lost some credibility internationally by flip-flopping on Paris (on top of Kyoto) and domestic climate action; as such, it may be considered important to submit a target that others believe can be achieved, even if it means being less “ambitious” in the first instance.

  • A fourth likely objective will be sustainability, i.e., rejoining Paris in a manner that promotes long-term U.S. participation. This could involve engaging in domestic outreach concerning the U.S. NDC.  By promoting domestic buy-in, outreach could make the NDC not only more credible in terms of achievability but more durable, reducing the extent to which the Paris Agreement and the U.S. NDC were later attacked; it could also provide substantive benefits, including taking advantage of input from the various actors (states, cities, companies, etc.) that have been taking climate action in the absence of the U.S. federal government.

  • A fifth likely objective will be international leverage. The new Administration might be able to use its re-joining moment to galvanize increased ambition from other key countries, including China and other major economies.  Ambition might relate to NDCs, mid-century strategies, sectoral arrangements, or other initiatives. The extent to which other countries could be pushed to do more in 2021 may depend upon whether/how much they increased their ambition in 2020, as well as how receptive they are to a United States that has changed its climate position yet again.  In some cases, other countries may hold back to a certain extent on increasing their ambition in 2020 precisely because they expect that, if there is a new U.S. Administration, it is likely to seek additional action in 2021.

How Do These Objectives Relate to Each Other?

Some of these objectives could be wholly compatible.  For example, if a new Administration chose to rejoin the Agreement right away, along with a very ambitious NDC, it could achieve immediacy and demonstrate climate ambition.  Alternatively, if the Administration waited to rejoin the Agreement and submit an NDC until it had pursued domestic law and engaged with domestic stakeholders and other countries, it could promote credibility, sustainability, and international leverage.

However, other objectives might be more oppositional.  For example, the immediate submission of a highly ambitious NDC might lack in credibility, given that the Administration would not yet know to what extent it could achieve the legal framework to back it up; at the same time, a credible NDC might lack in ambition. Immediacy would also appear to be at odds with taking the time to pursue domestic outreach and international consultations.

Are There Options for Rationalizing the Objectives?

Certain options could bring various objectives into alignment.  For example, assuming it were considered important to pursue the immediacyobjective, there are several conceivable approaches.

  • First, the Administration might rejoin Paris right away but hold off on submitting the NDC, making clear that it would do so once it had pursued legislative/regulatory changes, engaged in domestic outreach, and/or consulted with key countries. As noted, as a legal matter, a Party is supposed to have an NDC in place at all times; at the same time, other Parties would likely cut a new U.S. Administration some slack on the exact timing, particularly if it was a short window.

    • If the Administration disfavored a legal gap (e.g., because it did not want to set a bad precedent), it could delay both rejoining and submitting an NDC but announce right away that it “intends” to join the Agreement, either by a date certain or after consultations with Congress, domestic stakeholders, and international partners. The President might simultaneously issue an Executive Order to set up the process directing the development of the new NDC.
  • Second, if the Administration valued having an NDC in place at the time of rejoining the Agreement (and did not want to delay both), it would have the option of resubmitting the initial U.S. NDC, which, as noted, related to 2025. This would satisfy the requirement of having an NDC in place, while the Administration worked to develop its subsequent NDC.  A downside of this option is that a new Administration might not want to take on a target whose achievement was made much more difficult by the intervening policies of the Trump Administration.  As an alternative, pending the development of its subsequent target, the Administration might submit a 2025 target that the United States could more realistically achieve, taking into account, e.g., the actions of the U.S. Climate Alliance, the We Are Still In coalition, the Administration’s intended policies, etc.

  • Third, the United States could rejoin right away and submit a provisional or “placeholder” NDC relating to 2030 (or other date), making clear that the final NDC would be submitted at a later point. It could indicate a specific later point (e.g., a date certain, by the time of the 2021 Conference of the Parties), a variable time frame (e.g., after domestic and/or international consultations; after achievement of/progress on a domestic legislative framework), or leave it open.  In terms of content, a provisional/placeholder NDC could take different approaches:

    • It might set a floor, with the possibility of becoming more stringent (e.g., a target of “at least” X %). Such a formulation could promote credibility while leaving the door open to greater ambition if domestic and international circumstances ended up supporting it.
    • It might establish a range, with the (express or implied) expectation that the United States could go to the highest/higher end if domestic and international conditions proved favorable.
    • It could also take a two-tiered approach, with the more stringent second tier being conditional upon X or Y.


It should be recalled that the United States has twice used a range to reflect its emissions target. In addition to submitting a range under the Paris Agreement (26-28%), the United States, in 2009, needed to submit an emissions target under the Copenhagen Accord.  The House had passed the Waxman-Markey bill, but the Senate had not yet acted on it.  The Administration wanted to put forward a reasonable expectation of what was likely to emerge, but without preempting or prejudging the legislative process.  As such, the U.S. submission included a range target (“in the range of 17%” below 2005 levels in 2020), an express link to the domestic legislative process (“in conformity with anticipated U.S. energy and climate legislation”), and a commitment to submit a final target (“in light of enacted legislation”).

A provisional/placeholder NDC could be accompanied by an explanatory statement putting it in context.  It might, for example, recognize the need for a prosperous, carbon-neutral U.S. economy by 2050, express confidence that the challenge can be met, and note that this NDC (e.g., for 2030) is part of a plan that will need to accelerate U.S. emission reductions toward mid-century and beyond.

What Else Could the Administration Announce Right Away?

If the Administration chose to submit a provisional/placeholder NDC (or delay its submission), it could bolster the ambition aspect of rejoining Paris by announcing other climate-related actions and initiatives.

An announcement might include broad statements that reflect the Administration’s seriousness about climate change, such as U.S. support for climate science, a commitment to reach “net zero emissions” or “carbon neutrality” by a date certain, the intention to restore U.S. global leadership, the centrality of climate change to U.S. foreign policy, the need to pursue alignment of international agreements and institutions with Paris Agreement goals, etc.

In addition, an announcement might include more specific plans and proposals.  These could include:

  • what the Administration intends to do domestically (e.g., organize itself institutionally in a particular way to promote climate-aligned policies; put in place particular regulations; seek Congressional support for a specific type/stringency of climate legislation and/or certain contribution to the Green Climate Fund; pursue U.S. participation in the Kigali HFC Amendment to the Montreal Protocol; develop sector-specific approaches that could potentially be internationalized; commit to reinvigorating a U.S. clean energy research and development/innovation strategy; support U.S. sub-national initiatives); and

  • what the Administration intends to do internationally (e.g., indicating an intention to bring various policies (e.g., trade agreements, financing abroad) into alignment with Paris goals; reviving the Major Economies Forum and/or other initiatives involving sub-sets of relevant countries; re-establishing U.S. climate credibility in non-climate-specific fora, such as the G7, the G20, and the Arctic Council).

While such announcements would need to be supplemented by a finalized NDC at some point, they could at least serve as a clear and early indicator of a renewed U.S. commitment to climate action and leadership.

In addition, were the finalized U.S. NDC to end up closer to the “credible” end of the spectrum than the “highly ambitious” one, such policies would enhance the U.S. contribution to addressing the climate challenge beyond the narrower metric of the U.S. NDC.

*Susan Biniaz is a former Deputy Legal Adviser at the U.S. Department of State. She was the lead climate lawyer, and a negotiator, from 1989 until early 2017.  Since leaving the Government, she has been teaching at Yale Law School and the Yale Jackson Institute for Global Affairs. She has also been a David Sive Visiting Scholar at the Sabin Center for Climate Change Law.

+ posts