The Kyoto Protocol (Japanese: 京都議定書, Hepburn: Kyōto Giteisho) was an international agreement that expanded the 1992 United Nations Framework Convention on Climate Change (UNFCCC). It required countries to reduce greenhouse gas emissions, based on the idea that global warming is happening and that human-made carbon dioxide (CO₂) emissions are a major cause. The Kyoto Protocol was signed in Kyoto, Japan, on December 11, 1997, and became active on February 16, 2005. In 2020, 192 countries were part of the agreement, though Canada left the protocol in 2012.

The Kyoto Protocol aimed to lower greenhouse gas levels in the atmosphere to avoid harmful effects on the climate system, as stated in Article 2 of the UNFCCC. It focused on seven greenhouse gases listed in Annex A: carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulfur hexafluoride (SF₆), and nitrogen trifluoride (NF₃). Nitrogen trifluoride was added during the Doha Round for the second compliance period.

The protocol followed the principle of "common but differentiated responsibilities," meaning developed countries had greater responsibility to reduce emissions because they historically contributed more to current greenhouse gas levels.

The first commitment period of the Kyoto Protocol ran from 2008 to 2012. All 36 countries fully participating met their goals, but nine countries used flexibility mechanisms, such as funding emission reductions in other countries, to meet their targets. The 2008 financial crisis helped lower emissions. Countries in the former Eastern Bloc saw the largest reductions due to changes after the Soviet Union dissolved in the 1990s. Despite efforts by 36 developed countries, global emissions increased by 32% between 1990 and 2010.

A second commitment period was agreed to in 2012, called the Doha Amendment, extending the protocol to 2020. This period included 37 countries with binding targets, such as Australia, the European Union, Belarus, Iceland, Kazakhstan, Liechtenstein, Norway, Switzerland, and Ukraine. Belarus, Kazakhstan, and Ukraine considered leaving the protocol or not enforcing the amendment. Japan, New Zealand, and Russia participated in the first period but did not set new targets for the second. Canada left the protocol in 2012, and the United States never ratified it. Canadian leaders said leaving the protocol would avoid a $14 billion fine, which could harm the economy. As of October 2020, 147 countries had accepted the Doha Amendment, which became active on December 31, 2020. However, the second commitment period ended on the same day. Of the 37 countries with binding targets, 34 had ratified the amendment.

After the Kyoto Protocol’s second commitment period ended in 2020, UNFCCC Climate Change Conferences discussed future actions. This led to the 2015 Paris Agreement, a separate agreement under the UNFCCC, not an amendment to the Kyoto Protocol.

Chronology

In 1992, the United Nations Conference on the Environment and Development took place in Rio de Janeiro. This meeting led to the creation of the Framework Convention on Climate Change (UNFCCC), along with other agreements.

In 1995, countries that are part of the UNFCCC met in Berlin for the first Conference of the Parties (COP) to the UNFCCC. During this meeting, they discussed specific goals for reducing emissions.

In 1997, during December, countries reached an agreement in Kyoto, Japan, called the Kyoto Protocol. This agreement outlined general goals for reducing emissions.

In 2004, Russia and Canada officially approved the Kyoto Protocol to the UNFCCC. This action made the treaty effective on 16 February 2005.

In 2011, Canada became the first country to announce its decision to leave the Kyoto Protocol.

In 2012, the first commitment period under the Kyoto Protocol ended on 31 December 2012.

The official meeting of all countries that are part of the Kyoto Protocol is the annual Conference of the Parties (COP) to the United Nations Framework Convention on Climate Change (UNFCCC). The first COP meeting was held in 1995 in Berlin (COP 1). The first Meeting of Parties (CMP) of the Kyoto Protocol took place in 2005 alongside COP 11.

Objectives

The main goal of the Kyoto Protocol was to reduce human-caused greenhouse gas (GHG) emissions in a way that considers differences between countries, such as their levels of emissions, wealth, and ability to make reductions. The treaty follows the main principles from the 1992 UN Framework Convention on Climate Change. According to the treaty, Annex I countries that ratified the agreement were required to meet their GHG emission limits by 2012. These limits are listed in Annex B of the Protocol.

The Kyoto Protocol’s first commitment period (2008–2012) was the first detailed step under the UN Framework Convention on Climate Change. The Protocol created a system of repeated emission reduction periods. It set a timeline starting in 2006 for negotiations to establish emission reduction goals for a second commitment period. The first period’s emission reduction goals ended on December 31, 2012.

The first-round emission reduction goals under the Kyoto Protocol were not enough to keep greenhouse gas concentrations in the atmosphere at a steady level. Keeping GHG levels stable will require more reductions after the first-round commitment period ended in 2012.

The long-term goal of the UN Framework Convention on Climate Change (UNFCCC) is to "stabilize greenhouse gas concentrations in the atmosphere at a level that prevents dangerous human-caused changes to the climate system." Even if Annex I countries met their first-round goals, much larger reductions will be needed in the future to stabilize GHG levels.

For each human-caused greenhouse gas, different levels of emission reductions would be needed to achieve stabilization. Carbon dioxide (CO₂) is the most important human-caused GHG. Keeping CO₂ levels stable in the atmosphere would eventually require completely stopping human-caused CO₂ emissions.

To reach stabilization, global GHG emissions must first increase to a peak and then decrease. The lower the target stabilization level, the sooner the peak and decline must happen. For a given target, larger reductions now allow for smaller reductions later. However, smaller reductions now would require larger reductions later.

The first period of Kyoto emission limits can be seen as the first step toward stabilizing greenhouse gases in the atmosphere. In this way, the first period’s commitments may influence what future stabilization level can be achieved.

Principal concepts

The Kyoto Protocol includes several important ideas:

• Binding Commitments for Annex I Parties: The Kyoto Protocol requires countries in Annex I (mostly developed nations) to legally reduce greenhouse gas emissions. These requirements were based on the Berlin Mandate, a part of earlier UNFCCC negotiations.

• Implementation: Annex I countries must create policies to reduce emissions in their nations. They must also increase the absorption of greenhouse gases and use tools like joint implementation, the clean development mechanism, and emissions trading to earn credits that allow some emissions at home.

• Minimizing Impacts on Developing Countries: A fund was created to help developing countries adapt to climate change.

• Accounting, Reporting, and Review: These steps ensure the Kyoto Protocol is followed correctly.

• Compliance: A Compliance Committee was established to ensure countries meet their obligations.

The Kyoto Protocol includes three "flexibility mechanisms" to help Annex I countries meet their emission limits:

• International Emissions Trading (IET): This allows countries to buy and sell emissions allowances (Assigned Amount Units, or AAUs).
• Clean Development Mechanism (CDM): This encourages emission reductions in non-Annex I countries through projects.
• Joint Implementation (JI): This encourages emission reductions in Annex I countries through projects.

The flexibility mechanisms exist because the cost to reduce emissions varies between countries. Studies showed these tools could lower the overall cost of meeting emission targets and reduce economic losses for Annex I countries.

The CDM and JI are "project-based mechanisms," meaning they create emission reductions through specific projects. Unlike IET, which sets a limit on total emissions, the CDM and JI focus on producing emission reductions. The CDM supports projects in non-Annex I countries, while JI supports projects in Annex I countries.

Emission reductions from CDM and JI are measured against a hypothetical baseline of emissions that would have occurred without the project. These reductions are called Certified Emission Reductions (CERs) for CDM and Emission Reduction Units (ERUs) for JI. These are called "credits" because they represent reductions compared to a baseline.

Projects using nuclear energy are not eligible for CDM credits to avoid promoting nuclear technology exports.

Each Annex I country must report annual greenhouse gas emissions and removals under the UNFCCC and Kyoto Protocol. A designated national authority is chosen to manage these reports. Many non-Annex I countries also have a designated national authority to handle their Kyoto obligations, especially for the CDM process.

Emissions trading sets a total limit on emissions for all participating countries. Polluters who exceed their limit must buy emission rights from others. This can reduce reliance on fossil fuels and encourage investments in renewable energy like wind and solar power.

However, emissions trading schemes often do not align with global carbon budgets needed to keep warming below 1.5°C or "well below" 2°C. Surpluses of emission allowances can lead to low prices, reducing the impact on fossil fuel use. Prices for allowances vary widely, from €7 per tonne of CO₂ in China’s system to €63 per tonne in the EU-ETS (as of September 2021).

Other greenhouse gases can be traded, but their value is based on their global warming potential compared to CO₂.

An international coalition began forming at COP30 to create a global carbon market with a gradually decreasing emissions cap. This could reduce emissions seven times faster in participating countries and provide $200 billion annually for clean energy and social programs.

The European Union Emissions Trading Scheme (EU ETS) allows trade of Kyoto obligations between countries. However, most intergovernmental emissions trading outside the EU ETS has not occurred.

A major issue with IET is the large surplus of emission allowances. Countries like Russia, Ukraine, and some EU-12 members have excess allowances, while OECD countries often have deficits. Some surplus countries see this as compensation for economic restructuring. The surplus has been called "hot air," a term Russia finds offensive.

OECD countries with deficits could buy allowances from surplus countries to meet their Kyoto targets. However, without reducing the overall surplus, such trade might not lower emissions.

The Green Investment Scheme (GIS) is a plan to use surplus emission allowances (AAUs) under the Kyoto Protocol for environmental projects. The GIS aims to improve flexibility in meeting Kyoto targets while maintaining environmental integrity. However, the GIS is not required under the Kyoto Protocol, and no official definition exists.

Under the GIS, a country expecting to have surplus AAUs can sell them to another country. The money from these sales should be used for projects that reduce emissions or improve the environment.

Details of the agreement

The Kyoto Protocol is a formal agreement linked to the United Nations Framework Convention on Climate Change (UNFCCC), which was created during the Earth Summit in Rio de Janeiro in 1992. The UNFCCC did not include rules that required countries to follow specific limits on emissions or to enforce these rules. Only countries that are part of the UNFCCC can join the Kyoto Protocol. The Kyoto Protocol was created in 1997 during a meeting of the UNFCCC in Kyoto, Japan.

The Kyoto Protocol sets specific goals for reducing greenhouse gas (GHG) emissions for some countries. These goals do not include emissions from international air travel or shipping. Countries that are part of the Kyoto Protocol can use activities related to land use, land-use changes, and forestry (LULUCF) to help meet their targets. These activities are sometimes called "sink" activities because they can absorb carbon dioxide from the atmosphere. The Intergovernmental Panel on Climate Change reported that land-use changes since 1750 have contributed to about one-third of global warming. Specific rules define what types of forestry activities are included in the Kyoto Protocol.

Eligible LULUCF activities under the Kyoto Protocol include forest management, cropland management, grazing land management, and revegetation. Countries listed in Annex I of the UNFCCC (mostly industrialized nations) have limits on how much they can use forest management to meet their targets.

Under the Kyoto Protocol, 37 industrialized countries and the European Community (the European Union-15, which included 15 countries at the time of the Kyoto negotiations) agreed to legally binding targets for reducing emissions of six greenhouse gases: carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂O), sulfur hexafluoride (SF₆), hydrofluorocarbons (HFCs), and perfluorocarbons (PFCs). These gases are measured in terms of CO₂ equivalents to compare their impact on the climate. These reduction goals apply to emissions from the six gases listed, but not to emissions from industrial gases like chlorofluorocarbons (CFCs), which are addressed in a separate agreement called the Montreal Protocol.

Only countries listed in Annex I of the UNFCCC have legally binding targets for reducing emissions (called "quantified emission limitation and reduction objectives" or QELROs). Countries not listed in Annex I (mostly low-income developing countries) can participate in the Kyoto Protocol through the Clean Development Mechanism (CDM), which allows them to reduce emissions without bearing the costs themselves.

The emission reduction targets for Annex I countries vary. Some countries must reduce emissions below their 1990 levels, some must keep emissions at 1990 levels, and others may increase emissions slightly. Emission limits do not include emissions from international aviation or shipping. Belarus and Turkey are listed in Annex I but do not have emission targets because they were not Annex I countries when the Kyoto Protocol was created. Kazakhstan is not listed in Annex I but has expressed interest in joining.

The following countries have specific emission reduction targets based on their 1990 emissions levels:
– Australia: 108% (2.1% of 1990 emissions)
– Austria: 87%
– Belarus: 95% (subject to acceptance by other parties)
– Belgium: 92.5%
– Bulgaria: 92% (0.6%)
– Canada: 94% (3.33%) (withdrew)
– Croatia: 95%
– Czech Republic: 92% (1.24%)
– Denmark: 79%
– Estonia: 92% (0.28%)
– Finland: 100%
– France: 100%
– Germany: 79%
– Greece: 125%
– Hungary: 94% (0.52%)
– Iceland: 110% (0.02%)
– Ireland: 113%
– Italy: 93.5%
– Japan: 94% (8.55%)
– Latvia: 92% (0.17%)
– Liechtenstein: 92% (0.0015%)
– Lithuania: 92%
– Luxembourg: 72%
– Netherlands: 94%
– New Zealand: 100% (0.19%)
– Norway: 101% (0.26%)
– Poland: 94% (3.02%)
– Portugal: 92%
– Romania: 92% (1.24%)
– Russian Federation: 100% (17.4%)
– Slovakia: 92% (0.42%)
– Slovenia: 92%
– Spain: 115%
– Sweden: 104%
– Switzerland: 92% (0.32%)
– Ukraine: 100%
– United Kingdom: 87.5%
– United States of America: 93% (36.1%) (non-party)

For most countries, 1990 is the base year used to calculate emission targets. However, five countries used different base years:
– Bulgaria: 1988
– Hungary: average of 1985–1987
– Poland: 1988
– Romania: 1989
– Slovenia: 1986

Annex I countries can use various methods, such as reducing emissions from major industries or buying emission credits from other countries, to meet

Ratification process

The Kyoto Protocol was adopted by COP 3 of the UNFCCC on 11 December 1997 in Kyoto, Japan. It was opened for signature on 16 March 1998, and remained open for one year. During this time, countries such as Antigua and Barbuda, Argentina, the Maldives, Samoa, St. Lucia, and Switzerland signed the Protocol. At the end of the signature period, 82 countries and the European Community had signed. To become a party to the Protocol, countries needed to ratify it. Ratification began on 17 September 1998, with Fiji being the first country to ratify. Countries that did not sign could still join the Protocol by acceding to it, which has the same legal effect as signing.

Article 25 of the Protocol states that it will enter into force 90 days after at least 55 countries that are part of the UNFCCC, including countries in Annex I (which together account for at least 55% of carbon dioxide emissions from Annex I countries in 1990), have deposited their instruments of ratification, acceptance, approval, or accession.

The European Union and its member states ratified the Protocol in May 2002. The "55 parties" condition was met on 23 May 2002 when Iceland ratified the Protocol. The "55%" condition was met on 18 November 2004 when Russia ratified the Protocol. This caused the Protocol to enter into force on 16 February 2005, 90 days after Russia’s ratification.

As of May 2013, 191 countries and one regional economic organization (the European Community) had ratified the agreement. These countries represent over 61.6% of the 1990 emissions from Annex I countries. Among the 191 ratifying countries, Canada has renounced the Protocol.

The following countries have ratified the Protocol: Afghanistan, Albania, Algeria, Angola, Antigua and Barbuda, Argentina, Armenia, Australia, Austria, Azerbaijan, Bahamas, Bahrain, Bangladesh, Barbados, Belarus, Belgium, Belize, Benin, Bhutan, Bolivia, Bosnia and Herzegovina, Botswana, Brazil, Brunei, Bulgaria, Burkina Faso, Myanmar, Burundi, Cambodia, Cameroon, Canada, Cape Verde, Central African Republic, Chad, Chile, China, Colombia, Comoros, Democratic Republic of the Congo, Republic of the Congo, Cook Islands, Costa Rica, Ivory Coast, Croatia, Cuba, Cyprus, Czech Republic, Denmark, Djibouti, Dominica, Dominican Republic, Ecuador, East Timor, Egypt, El Salvador, Equatorial Guinea, Eritrea, Estonia, Eswatini, Ethiopia, European Union, Fiji, Finland, France, Gabon, Gambia, Georgia, Germany, Ghana, Greece, Grenada, Guatemala, Guinea, Guinea-Bissau, Guyana, Haiti, Honduras, Hungary, Iceland, India, Indonesia, Iran, Iraq, Ireland, Israel, Italy, Jamaica, Japan, Jordan, Kazakhstan, Kenya, Kiribati, North Korea, South Korea, Kuwait, Kyrgyzstan, Laos, Latvia, Lebanon, Lesotho, Liberia, Libya, Liechtenstein, Lithuania, Luxembourg, Madagascar, Malawi, Malaysia, Maldives, Mali, Malta, Marshall Islands, Mauritania, Mauritius, Mexico, Federated States of Micronesia, Moldova, Monaco, Mongolia, Montenegro, Morocco, Mozambique, Namibia, Nauru, Nepal, Netherlands, New Zealand, Nicaragua, Niger, Nigeria, Niue, North Macedonia, Norway, Oman, Pakistan, Palau, Panama, Papua New Guinea, Paraguay, Peru, Philippines, Poland, Portugal, Qatar, Romania, Russia, Rwanda, Saint Kitts and Nevis, Saint Lucia, Saint Vincent and the Grenadines, Samoa, San Marino, São Tomé and Príncipe, Saudi Arabia, Senegal, Serbia, Seychelles, Sierra Leone, Singapore, Slovakia, Slovenia, Solomon Islands, Somalia (non-party to Kyoto), South Africa, Spain, Sri Lanka, Sudan, Suriname, Sweden, Switzerland, Syria, Tajikistan, Tanzania, Thailand, Togo, Tonga, Trinidad and Tobago, Tunisia, Turkey, Turkmenistan, Tuvalu, Uganda, Ukraine, United Arab Emirates, United Kingdom, United States (non-party to Kyoto), Uruguay, Uzbekistan, Vanuatu, Venezuela, Vietnam, Yemen, Zambia, Zimbabwe.

Andorra (non-party to Kyoto) and the Holy See (non-party to Kyoto) are not parties to the Protocol.

The United States signed the Protocol on 12 November 1998 during the Clinton administration. However, for the Protocol to become legally binding in the US, it needed to be ratified by the US Senate. In 1997, the Senate passed the non-binding Byrd-Hagel Resolution, which expressed disapproval of any international agreement that did not require developing countries to reduce emissions and warned that the Protocol could harm the US economy. The resolution passed 95–0. As a result, the Clinton administration did not submit the Protocol to the Senate for ratification.

At the start of the Bush administration, Senators Chuck Hagel, Jesse Helms, Larry Craig, and Pat Roberts wrote to President George W. Bush to ask about his position on the Kyoto Protocol and climate change policy. In a letter dated 13 March 2001, President Bush stated that his administration took climate change seriously but opposed the Kyoto Protocol because it excluded 80% of the world’s population, including major countries like China and India, and could harm the US economy. He also questioned the scientific certainty of climate change and cited potential economic harms from emissions reductions.

The Tyndall Centre for Climate Change Research reported in 2001 that President Bush’s comments were an overstatement used to justify support for the US oil and coal industries, which had strong influence in the administration and among conservative Republican lawmakers.

As of 2023, the United States is the only signatory that has not ratified the Protocol. In 1990, the US accounted for 36.1% of global emissions. For the Protocol to go into legal effect without US ratification, a coalition including the EU, Russia, Japan, and other small parties would be required. A deal without US participation was reached during the Bonn climate talks (COP-6.5) in 2001.

In 2011, Canada, Japan, and Russia stated they would not take on further Kyoto targets. Canada announced its withdrawal from the Protocol on 12 December 2011, effective 15 December 2012. Canada had committed to reducing its greenhouse gas emissions to 6% below 1990 levels by 2012 but failed to meet this goal, with emissions in 2009 being 17% higher than in 1990. The Harper government prioritized oil sands development in Alberta and reduced efforts to cut emissions. Environment Minister Peter Kent cited the risk of "enormous financial penalties" under the Protocol as a reason for withdrawal. He also suggested that the

Country types and their emissions

Total greenhouse gas (GHG) emissions, not including emissions from land use, land use change, and forestry (LULUCF), for all Annex I Parties (see list below), including the United States, decreased from 19.0 to 17.8 thousand teragrams (Tg, which is equal to 1,000,000,000 kg) CO₂ equivalent, a drop of 6.0% between 1990 and 2008. Several reasons contributed to this decrease. One reason is economic changes in the Annex I Economies in Transition (EITs). Between 1990 and 1999, emissions in EITs dropped by 40% after the collapse of central planning in former Soviet Union and Eastern European countries. This led to a large decline in heavy industry, reducing fossil fuel use and emissions.

Emissions growth among Annex I Parties was limited due to policies and measures (PaMs). After 2000, PaMs improved, helping increase energy efficiency and develop renewable energy. Energy use also dropped during the 2007–2008 economic crisis.

The group of industrialized countries that agreed to a Kyoto target (Annex I countries excluding the United States) aimed to reduce their average GHG emissions by 4.2% between 2008 and 2012 compared to 1990 levels.

As noted earlier, between 1990 and 1999, emissions in EITs fell significantly. This reduction is the main reason for the overall decrease in GHG emissions (excluding LULUCF) for Annex I countries (excluding the United States). Emissions from Annex II countries (Annex I countries without EITs) rose slightly from 1990 to 2006, then stabilized and decreased after 2007. The early 1990s reductions by 12 EIT countries that later joined the European Union (EU-27) helped the EU meet its Kyoto target.

In December 2011, Canada’s environment minister, Peter Kent, officially announced Canada would leave the Kyoto agreement one day after the 2011 United Nations Climate Change Conference (see the section on Canada’s withdrawal).

Belarus, Malta, and Turkey are Annex I Parties but did not have initial Kyoto targets. The United States had a Kyoto target of reducing emissions by 7% from 1990 levels but did not ratify the treaty. If the United States had ratified the Kyoto Protocol, the average GHG emission reduction for Annex I countries would have been 5.2% compared to 1990 levels.

The United Nations Framework Convention on Climate Change (UNFCCC, 2005) collected and summarized information from non-Annex I Parties. Most non-Annex I Parties were low-income countries, with few classified as middle-income. Many provided details about policies related to sustainable development, such as reducing poverty, improving education, and increasing access to healthcare. Many non-Annex I Parties are updating their environmental laws to address global issues like climate change.

A few countries, such as South Africa and Iran, expressed concerns that efforts by Annex I Parties to reduce emissions could harm their economies. These countries rely heavily on income from producing, processing, and exporting fossil fuels.

GHG emissions, excluding land use change and forestry (LUCF), reported by 122 non-Annex I Parties for 1994 or the nearest available year, totaled 11.7 billion tonnes (1,000,000,000 tonnes) of CO₂ equivalent. CO₂ made up the largest share (63%), followed by methane (26%) and nitrous oxide (N₂O) (11%).

The energy sector was the main source of emissions for 70 countries, while the agriculture sector was the main source for 45 countries. On average, per capita emissions (in tonnes of CO₂ equivalent, excluding LUCF) were 2.8 tonnes for the 122 non-Annex I Parties.

• The Africa region’s total emissions were 1.6 billion tonnes, with an average of 2.4 tonnes per person.
• The Asia and Pacific region’s total emissions were 7.9 billion tonnes, with an average of 2.6 tonnes per person.
• The Latin America and Caribbean region’s total emissions were 2.0 billion tonnes, with an average of 4.6 tonnes per person.
• The “other” region includes Albania, Armenia, Azerbaijan, Georgia, Malta, Moldova, and North Macedonia. Their total emissions were 0.1 billion tonnes, with an average of 5.1 tonnes per person.

Parties reported high uncertainty in LUCF emissions, but overall, the difference between including and excluding LUCF was small (1.7%). Including LUCF, emissions totaled 11.9 billion tonnes, while excluding LUCF, emissions totaled 11.7 billion tonnes.

Problem areas

Gupta et al. (2007) studied the literature about climate change policies. They found that no official evaluations of the UNFCCC or its Protocol claimed these agreements would solve the climate problem. In these studies, it was assumed the UNFCCC or its Protocol would not be changed. The Framework Convention and its Protocol include plans for future actions to address climate change.

Gupta et al. (2007) described the Kyoto first-round commitments as "modest," meaning they limited the treaty's ability to reduce emissions. Experts suggested that future Kyoto commitments could be more effective if they included stronger efforts to cut emissions and applied policies to a larger share of global emissions. In 2008, countries with Kyoto emission limits covered less than one-third of the world's carbon dioxide emissions from fuel use.

The World Bank (2010) noted that the Kyoto Protocol had only a small effect on slowing global emissions growth. The treaty was created in 1997, but by 2006, energy-related carbon dioxide emissions had increased by 24%. The World Bank also stated that the treaty provided limited financial help to developing countries to reduce emissions and adapt to climate change.

Some environmentalists supported the Kyoto Protocol because it was "the only game in town," meaning it was the only major international agreement on emissions. They also believed future commitments might require stricter emission reductions. In 2001, seventeen national science academies said ratifying the Protocol was a "small but essential first step" toward stabilizing greenhouse gas levels. Others criticized the current commitments for being too weak.

The United States (under former President George W. Bush) and Australia (under former Prime Minister John Howard) did not ratify the Kyoto Protocol. Stern (2006) explained their decision was based on the lack of emission limits for developing countries. Australia later ratified the treaty under former Prime Minister Kevin Rudd, and it became effective in March 2008.

Thirty-eight developed countries agreed to limit their greenhouse gas emissions. However, the United States did not ratify the treaty, and Canada withdrew, leaving 36 countries with emission limits. All 36 countries followed the Protocol. Nine of them (Austria, Denmark, Iceland, Japan, Lichtenstein, Luxembourg, Norway, Spain, and Switzerland) used flexibility mechanisms because their emissions slightly exceeded their targets.

The 36 countries committed to reducing emissions by 4% compared to 1990 levels. Their average emissions in 2008–2012 were 24.2% lower than in 1990, meaning they met their goal by a large margin. Including the United States and Canada, global emissions dropped by 11.8%. These reductions were largely due to the collapse of the Soviet Union, which sharply reduced emissions in Eastern Europe in the 1990s, and the 2008 financial crisis, which cut emissions during the Kyoto commitment period.

The 36 countries that reduced emissions made up 24% of global greenhouse gas emissions in 2010. Even though they cut their emissions significantly, other countries increased theirs so much that global emissions rose by 32% from 1990 to 2010.

Several large developing countries and fast-growing economies (China, India, Thailand, Indonesia, Egypt, and Iran) saw rapid increases in greenhouse gas emissions (PBL, 2009). For example, China's emissions rose strongly from 1990 to 2005, often by more than 10% per year. Emissions per person in non-Annex I countries are still much lower than in industrialized countries. These countries do not have specific emission reduction targets but are required to take steps to reduce emissions. China, for example, has a national plan to slow emissions growth, including closing outdated coal-fired power plants.

The Kyoto flexibility mechanisms—carbon trading, Joint Implementation, and the Clean Development Mechanism (CDM)—have received both praise and criticism. Supporters argue these mechanisms help developed countries meet their emission goals more affordably. Critics say carbon trading does not encourage investment in clean energy and that CDM projects sometimes harm local communities in developing countries.

China, India, Indonesia, and Brazil were not required to reduce their carbon dioxide emissions. Other signatory countries were not obligated to follow a common framework or specific measures but were required to meet emission targets. They could buy carbon credits from other countries through a multilateral carbon trading system. This allowed countries to host polluting industries and purchase environmental benefits from others.

A 2021 review examined the design of the Kyoto Protocol and the political strategies that influenced its adoption. It concluded the Protocol's limited impact on global emissions was due to factors like "deliberate political strategy, unequal power, and the absence of leadership" among nations. Efforts by fossil fuel companies and conservative groups to spread misinformation about climate change have affected public opinion and slowed political action on climate issues in the United States and globally. Direct lobbying by fossil fuel companies and their financial support for political leaders have slowed climate action at local, national, and international levels.

Amendment and successor

In the non-binding "Washington Declaration" signed on 16 February 2007, leaders from Canada, France, Germany, Italy, Japan, Russia, the United Kingdom, the United States, Brazil, China, India, Mexico, and South Africa agreed on the general plan for a new agreement to replace the Kyoto Protocol. They planned a global system where countries would have limits on emissions and could trade credits. They hoped this system would be ready by 2009.

The United Nations Climate Change Conference in Copenhagen in December 2009 was part of a series of yearly meetings started after the 1992 Earth Summit in Rio. In 1997, these talks led to the Kyoto Protocol. The Copenhagen meeting was seen as a chance to create a new agreement to replace Kyoto and reduce carbon emissions effectively.

The 2010 Cancún agreements included promises from 76 developed and developing countries to control their greenhouse gas emissions. In 2010, these 76 countries were responsible for 85% of the world's annual greenhouse gas emissions.

By May 2012, the United States, Japan, Russia, and Canada said they would not join a second Kyoto commitment period. In November 2012, Australia said it would join the second commitment period under the Kyoto Protocol, while New Zealand said it would not.

New Zealand’s climate minister, Tim Groser, stated the Kyoto Protocol, which was 15 years old, was outdated and that New Zealand was “ahead of the curve” in seeking a replacement that includes developing nations. Non-profit environmental groups, such as the World Wildlife Fund, criticized New Zealand’s decision to leave the agreement.

On 8 December 2012, at the end of the 2012 United Nations Climate Change Conference, an agreement was reached to extend the Kyoto Protocol until 2020 and set a date of 2015 for creating a new agreement to be used starting in 2020. The outcome of the Doha talks received mixed reactions, with small island nations criticizing the overall plan. The Kyoto second commitment period covers about 11% of the world’s annual greenhouse gas emissions. Other results from the conference included a plan for a global agreement to be adopted by 2015, involving all countries. At the Doha meeting, the European Union’s chief climate negotiator, Artur Runge-Metzger, promised to extend the Kyoto Protocol, which applies to the 27 European Union member states, until 2020, pending approval within the EU.

Ban Ki-Moon, the United Nations Secretary-General, urged world leaders to agree on ways to stop global warming during the 69th Session of the UN General Assembly on 23 September 2014 in New York. The next climate summit was held in Paris in 2015, where the Paris Agreement, the replacement for the Kyoto Protocol, was created.