Commitment Cycles and the Ratchet Mechanism


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Last updated September 28, 2015

One of the big questions facing the negotiations is whether the agreement arrived at in 2015 should direct climate action for decades to come, and if so, how. This question has become starkly relevant as it is now clear that the recently submitted Intended Nationally Determined Contributions (INDCs) will only direct global action for 10 years, and will only push global action part of the way towards the 2˚C pathway.

Laying the Ground Work for Beyond Paris in Paris: Introducing Cycles and a Ratchet Mechanism

Parties will need to undertake major additional action beyond the INDCs if they wish to keep warming within 2˚C and avoid the worst impacts of climate change. Towards this end, parties are currently considering whether to establish a regular schedule for revisiting international commitments for climate action. Within the current draft text, put together in Geneva and partially streamlined in Bonn, there are two concepts that have been designed to address this question: cyclical commitment and assessment periods that together could constitute a ratchet mechanism.

A ratchet mechanism is one way to make the Paris agreement durable and relevant over a long period of time. This mechanism would augment contributions offered at the Paris meetings with a process to promote post-Paris actions by both national and non-state actors in order to guide global action towards the 2˚C pathway.

What Purpose does a Ratchet Serve: Key Functions of Cycles and a Ratchet

A rachet built on regular, recurring cycles of assessment and a schedule for revisiting country commitments would serve two key functions. The assessments would establish how far a country's actions have moved global emissions toward the 2˚C pathway, and the schedule for revisiting country commitments would provide a process to increase, over time, the ambition of the climate targets set by countries. A no-backsliding provision is another element proposed for inclusion into the rachet mechanism.

How are Countries Positioned on the Inclusion and Preferred Form of Cycles and a Ratchet

National positions on assessment and reviews cycles differ markedly. Several permutations exist for how to schedule cycles and build a ratchet mechanism. (In the draft ADP negotiating text, see Section D paragraph 19 and 21 and Section J paragraph 167 and 172.) Several negotiating parties have made a distinction between the length of the commitment cycle (the timespan in which a target should be achieved) and the length between assessments of progress towards that target, which may not operate on the same timeline.

Several developed countries have called for five-year assessment periods, with some advocating for longer commitment cycles. Simultaneously, several developing countries are pushing for a longer timeframe or for two different timeframes, a shorter one for developed countries and a longer one for developing countries. Currently, the United States and AOSIS support five-year cycles for both commitments and assessments. In a recent development, the EU, which had previously favored a 10-year commitment cycle with assessments every five years came forward in the August-September Bonn session and publicly endorsed regularly 5-year assessment  cycles starting in the year 2020. China and India had both been pushing for 10-year periods for both targets and assessments. However, consensus has been evolving towards 5-year cycles as a result of discussions in high-level ministerials meetings held throughout the summer and continuing into the Fall. Differing opinions on when to schedule the first assessment - whether in 2020, 2025, or after 2030 - still mark the negotiations and 5-year assessment cycles are becoming more likely but are still not fully baked into the emerging Paris agreement.

Another key question centers on the length of the first commitment period. While the U.S. submitted an INDC that runs until 2025, the EU and China submitted INDCs that run until 2030. Some advocates have argued that locking in emissions policy until 2030 creates an unnecessary obstacle to reducing emissions by discouraging countries from taking advantage of any technical and economic changes that arrive over the next 15 years. These advocates argue that a 10-year outlook, as opposed to a 15-year span, is sufficient to provide the predictability called for by investors and planners.

On September 25 the U.S. and China Endorsed Common Language about a Ratchet

In the breakthrough announcement that the world's two biggest emitters and largest economies made public on September 25th, both countries signed onto the following common language on a ratchet: "As part of their commitment to a successful and ambitious Paris outcome, the two countries articulated a set of shared understandings for the agreement, including onthe importance of a successful agreement that ramps-up ambition over time, pointing toward a low-carbon transformation of the global economy this century." 

While the joint statement put out by the governments of China and the U.S. does not specify how countries will ramp up the ambition in their pledges or what rules they will follow for deciding how much or how little to ramp up ambition the fact that both countries have formally committed to some form of increased ambition post-2030 is incredibly significant and means that it is almost guarantueed to feature in the Paris package.

Designing a Ratchet: Setting the Scope and Structure of a Ratchet Mechanism

Further, there are emerging questions over what a periodic assessment and revisiting process should cover. Negotiators continue to debate whether the scope should be limited to emissions reductions and climate change mitigation targets and activities, or if it should also include reviews and revisions of adaptation and finance commitments. The view supporting an expanded focus beyond just mitigation gained some traction during the Bonn discussions in June, but no resolution was reached by the end of the session.

Beyond the questions of scope, there are various options for what the components of a ratchet mechanism would be. Possible components include:

  • An ex-ante review in which an assessment of a country’s commitment is made after it is proposed, but prior to final submission. It would look at that country’s level of effort on climate change relative to the total global effort.

  • A judgment on the aggregate adequacy of all commitments.

  • Some machinery for compelling or facilitating a commitment requiring greater effort if the contribution tabled is inadequate. This machinery could involve a set of incentives, like supplemental financial or technical assistance.

Each part of this three-fold structure could take multiple forms and has not been well defined to date.

Reflecting the Ratchet in the Paris Package: Where in the Negotiating Text will a Ratchet be Embedded

It is not yet guaranteed that clear commitment periods or a mandate for a set of rules to ramp up the ambition of commitments over time will be kept in the final agreement text adopted in Paris. Several parties have voiced a preference for relocating provisions on cycles and timeframes to a separate COP decision document that will accompany the formal legal agreement, as these topics may require periodic updates and will likely lack the durability of content in the formal agreement text.

If there are provisions anchored into either the agreement or the decision text, which seems to be a likely outcome, it is still unclear if parties will incorporate a consolidated rachet mechanism or design separate processes for increasing ambition. A consolidated ratchet mechanism would be defined in one section of the agreement or accompanying COP decisions, while the separate processes for increasing ambition over time could be sprinkled across the text—for example, the increase of adaptation commitments could be approached separately from mitigation or finance commitments.

Moving Towards a Consensus around 5-Year Cycles

While clarity is still lacking on the potential scope and structure of a ratchet mechanism would take, some promising reports emerged from a set of ministerial meetings held in late July on the timeframe for review cycles. At the conclusion of closed meetings chaired by the the French Presidency of COP21, France’s lead negotiator on climate change stated that consensus was building at a high political level to establish five-year commitment and assessment cycles as part of the Paris agreement.

In the August-September Bonn session the high-level convergence on this issue forged in informal sessions over the summer did seem to trickle down to negotiations over the Paris text itself and move discussions over the text towards a clearer set of options on structure and placement.

In the first week of October, the presiding co-chairs of the climate negotiations will release another streamlined draft agreement text that will underpin the discussions going into the third round of formal negotiating sessions in Bonn. It remains to be seen if this next iteration of the document will clarify how and where ratchets and commitment cycles will be embedded in the text.


Key Terms


The Ad Hoc Working Group on the Durban Platform for Enhanced Action (ADP) is a body created by the UN Framework Convention on Climate Change (UNFCCC). Its mission is to "develop a protocol, another legal instrument or an agreed outcome with legal force under the Convention applicable to all Parties, which is to be completed no later than 2015 in order for it to be adopted at the twenty-first session of the Conference of the Parties (COP) and for it to come into effect and be implemented from 2020." 

African Group of Negotiators

The African Group of Negotiators (AGN) represents African nations in the United Nations system. At the 20th Conference of Parties, the AGN associated itself with the G77 and China and has historically had strong ties with the positions of that negotiating bloc.  



The Independent Association of Latin American and the Caribbean (AILAC) represents six regionally proximate countries with similar positions on climate change. AILAC is officially comprised of Chile, Colombia, Costa Rica, Guatemala, Panama, and Peru. 


ALBA, formally known as the Bolivarian Alliance for the Peoples of Our America, is a negotiating bloc with 11 member countries in Central America, South America, and the Caribbean. It is associated with socialist and social democratic governments and operates under a vision of a Hispanic system of solidarity and mutual aid.

Annex I

A term used to refer to industrialized countries that were members of the Organisation for Economic Co-operation and Development (OECD) at the Earth Summit in Rio de Janiero in 1992, and countries with economies in transition. Examples of Annex I countries include the United States, member states of the European Union, and the Russian Federation.


The Association of Small Island States (AOSIS) represents 44 island and low-lying coastal countries with similar development challenges and environmental concerns. AOSIS lobbies and negotiates for small island developing states (SIDS) in the United Nations system. Climate change is a fundamental threat to many SIDS, and AOSIS has called for major global  emissions reductions at every international climate negotiation. Some members include Cuba, Samoa, Trinidad and Tobago, Marshall Islands, and Maldives.


The 5th Asssessment Report (AR5) is an extensive document of the future threats and current impacts of climate change, published by the Intergovernmental Panel on Climate Change (IPCC) in 2013 and 2014. 


The Association of Southeast Asian Nations (ASEAN) represents ten member states in Southeast Asia, including Indonesia, Malaysia, the Philippines, Singapore, and Thailand. ASEAN has a special working group on climate change that focuses on addressing climate change in the global community.


The BASIC group consists of Brazil, South Africa, India, and China. These four newly industrialized countries walked out of the Copenhagen climate summit, and often argue for equitable development and consideration of common but differentiated responsibilities and capabilities (CBDR-RC). There is a high level of overlap between BASIC and BRICS nations.


Brazil, Russia, India, China, and South Africa make up the BRICS nations. These five major emerging national economies play a significant role in global negotiations and represent around 40% of the global population. There is a high level of overlap between BASIC and BRICS nations.


Central Asia, Caucasus, Albania, and Moldova (CACAM) have formed a negotiating group for United Nations proceedings.

Cartagena Dialogue

The Cartagena Dialogue is an informal alliance of around 40 developed and developing countries party to the UN Framework Convention on Climate Change (UNFCCC) process. The dialogue meets outside of the formal negotiations to discuss progressive climate objectives.


A guiding principle as well as a source of contention in the UN climate negotiations, Common but Differentiated Responsbilities and Capabilities (CBDR–RC) takes account of a country's historic contributions to climate change, as well as its ability to contribute to a global response.

Climate Finance

Mechanisms established to help fund countries in their efforts to reduce emissions and adapt to the impacts of climate change.


The 15th Session of the Conference of Parties to the United Nations Framework Convention on Climate Change, held in Copenhagen, Denmark.


The official and commonly used acronym for the 17th Session of the Conference of Parties to the United Nations Framework Convention on Climate Change (COP17), held in Durban at the end of 2011. At COP17, countries – including the United States, China and India – agreed to reach a legally binding treaty to address climate change post–2020, by 2015.


The 20th Session of the Conference of Parties to the United Nations Framework Convention on Climate Change, held in Lima, Peru. At COP20, the draft text for the Paris Agreement was produced, including proposed language for a long term goal.


A common acronym for the 21st session of the Conference of the Parties to the United Nations Framework Convention on Climate Change, which is being held in Paris in November and December of 2015. 


Capital city of Denmark and host of the 15th Session of the Conference of Parties (COP15) to the United Nations Framework Convention on Climate Change (UNFCCC) in 2009.  

Copenhagen Accord

The result of the 15th Session of the Conference of Parties (COP15) to the United Nations Framework Convention on Climate Change (UNFCCC). The accord included a long-term goal of limiting warming to no more than 2˚C above pre–industrial levels, but excluded practical terms for achieving this goal.

Durban Platform

A common label applied to the deal reached at the 17th Session of the Conference of Parties (COP17) to the United Nations Framework Convention on Climate Change (UNFCCC), held in Durban at the end of 2011. Countries – including the United States, China and India – agreed to reach a legally binding treaty to address climate change post–2020, by 2015.


Formed in 2000, the Environmental Integrity Group (EIG) is made up of Mexico, Liechtenstein, Monaco, South Korea, and Switzerland. These nations formed this group because they did not feel represented by any groups that arose out of the 4th Conference of Parties (COP4) in 1998.

European Union (EU) Group

The European Union (EU) consists of 28 member states, and meets privately to develop unified negotiating positions. The European Commission presidency is rotated between members every six months, and the president is responsible for speaking for the EU and all member nations. The EU can be itself a party to the climate convention or to other organizations, but generally does not have a separate vote from its members.


The Group of 77 (G77) is the largest group of developing countries participating in the Paris climate talks. This group is very diverse and represents a broad variety of interests and positions. Some notable members of the G77 include Brazil, China, Mexico, South Korea, Chile, India, and Saudi Arabia.


The Green Climate Fund (GCF) is a fund set up through the United Nations Framework Convention on Climate Change (UNFCCC) with the intent to raise money from the developed world to help developing countries to reduce emissions and cope with the impacts of climate change. 


A greenhouse gas (GHG) traps heat in the atmosphere, which leads to global warming. Carbon dioxide (CO2), methane (CH4), and nitrous oxide (NO) are three common greenhouse gases.  Most greenhouse gasses are addressed by the UNFCCC, but a small handful of fluorinated GHG (aka F-gases) are currently addressed by the Montreal Protocol which seeks to manage a different issue, ozone depletion.


Intended Nationally Determined Contributions (INDCs) are outlines of the actions that countries intend to take to address climate change, submitted ahead of the Paris negotiations. 

International Climate and Forest Initiative (NICFI)

An initiative advanced by Norway to help establish a global, binding, long-term post-2012 regime to limit global temperature rise to below 2°C. It contributes to multilateral and bilateral initiatives including the Brazilian Amazon Fund, Congo Basin Forest Fund, Forest Carbon Partnership Facility and Forest Investment Program.


The Intergovernmental Panel on Climate Change (IPCC) was established by the UN Environment Programme (UNEP) and the World Meteorological Organization (WMO) in 1988 to scientifically assess and communicate the risks and challenges posed by climate change. 

Kyoto Protocol

An international climate agreement that commits countries to reduce greenhouse gas emissions toward established, legally binding targets, linked to the United Nations Framework Convention on Climate Change. It was adopted in 1997 in Kyoto, Japan, and came into force in February 2005. 

League of Arab States

The League of Arab States represents 21 independent Arab states in northern and northeastern Africa and southwest Asia. The League of Arab States was founded by Egypt, Iraq, Jordan, Lebanon, Syria, and Saudi Arabia, although Syria is currently suspended.

Least Developed Countries (LDCs)

Forty-eight countries are categorized as least developed countries (LDCs) by the United Nations. LDCs have been active as a negotiating bloc in the climate change talks in recent years, and often advocate for adaptation financing.

Like Minded Developing Countries (LMDC) Group

The Like Minded Group of Developing Countries (LMDC) is a new negotiating bloc that represents over 50% of the global population. The LMDCs, which include Venezuela, Iran, Saudi Arabia, and India, indicated during the 20th Conference of Parties that common but differentiated responsibilities and capabilities (CBDR-RC) would be a critical issue during the negotiating process. Adaptation financing and historical responsibility are two common negotiating points for the LMDCs. The LMDCs also often advocate for the maintenance of the differentiation between developed and developing countries (Annex 1 and Annex 2, in UN parlance).


Capital city of Peru and host of the 20th Conference of Parties (COP20) to the United Nations Framework Convention on Climate Change (UNFCCC).

Long-Term Goal (LTG)

A long-range goal that would help orient and guide global activity to avert catastrophic climate change. The shape and nature of this goal is still being determined, but may form a key piece of the Paris agreement.

Loss and Damage

A term used to describe climate impacts that occur when the limits of adaptation are reached. The United Nations Framework Convention on Climate Change has developed a work programme on loss and damage to help address the issue, particularly for the developing countries most vulnerable to the impacts of climate change.


A long-term goal (LTG) that would help orient and guide global activity to avert catastrophic climate change. The shape and nature of this goal is still being determined, but may form a key piece of the Paris agreement.


A greenhouse gas inventory sector that covers emissions and removals of greenhouse gases resulting from direct human-induced land use, land-use change and forestry activities.

Non–Annex I

Mostly developing countries, many of which are recognized as being at greater risk from the impacts of cliamte change or whose economies are disproportionately reliant on fossil fuel production. Examples of non–Annex I countries include Angola, Bangladesh and Fiji.  


The Organization of Petroleum Exporting Countries (OPEC) is an intergovernmental organization that often states positions on international negotiations. Twelve countries currently belong to OPEC, which was founded by Iran, Iraq, Kuwait, Saudi Arabia, and Venezuela. OPEC has taken a strong position against long-term goals that mandate shifts away from fossil fuels.

Organization for Economic Cooperation and Development (OECD)

Thirty-four member countries and the European Commission take part in the work of the Organization for Economic Cooperation and Development (OECD). The OECD is dedicated to global development and understanding economic, social, and environmental change. Notable members include Australia, Canada, Germany, the United Kingdom, and the United States.

Pacific Alliance

The Pacific Alliance is a Latin American trading bloc consisting of Chile, Columbia, Mexico, and Peru. They have collectively called for concrete measures toward a global agreement on climate change.

Paris Agreement

A label widely used to refer to the international climate agreement countries have committed to creating before the end of the talks being held in Paris in November and December of 2015.

Paris Climate Talks

A commonly used shorthand for the 21st Conference of the Parties (COP21) to the United Nations Framewrok Convention on Climate Change, which is being held in Paris in November and December of 2015. 


The Central American Integration System (SICA) consists of Costa Rica, the Dominican Republic, El Salvador, Guatemala, Honduras, Nicaragua, Panama, and Belize. As members of the Group of 77, this negotiating bloc aligned itself with the Lima statement from the G77 and China.

South-South Cooperation Fund

A climate finance fund announced by China in September 2014 with the intent to provide greater assistance to developing countries in tackling climate change. 

Umbrella Group

The Umbrella Group is an informal group made up of non-EU developed countries. Its formation occurred following the Kyoto Protocol adaptation, and its non-codified member list usually includes Australia, Japan, Canada, New Zealand, Kazakhstan, Norway, Russia, Ukraine, and the United States.


The United Nations Development Programme works with 170 countries around the world to eradicate poverty and reduce inequality and exclusion. 



The United Nations Framework Convention on Climate Change (UNFCCC) is a near-universal climate treaty established at the 1992 Earth Summit in Rio de Janeiro.