Editing IPCC:AR6/WGIII/Chapter-14 (section)

==== 14.3.3.1 Ex-post Assessment of the Kyoto Protocol’s Effects ====

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Previous assessment reports have assessed the Kyoto Protocol with respect to each of the criteria identified in this chapter. However, at the time of AR5, it was premature to assess the impact of Kyoto on emissions, as these data had not been entirely compiled yet. Since AR5, a number of studies have done so. [[IPCC:Wg3:Chapter:Chapter-2|Chapter 2]] of this report lists at least 18 countries that have sustained absolute emissions reductions for at least a decade, nearly all of which are countries that had Kyoto targets for the first commitment period. Most studies have concluded that Kyoto did cause emissions reductions. Such studies find a positive, statistically significant impact on emissions reductions in Annex I countries ( [[#Kim--2020|Kim et al. 2020]] ), Annex B countries ( [[#Grunewald--2012|Grunewald and Martínez-Zarzoso 2012]] ; Kumazawa and Callaghan 2012; [[#Grunewald--2016|Grunewald and Martínez-Zarzoso 2016]] ; [[#Maamoun--2019|Maamoun 2019]] ), or all countries respectively ( [[#Aichele--2013|Aichele and Felbermayr 2013]] ; [[#Iwata--2014|Iwata and Okada 2014]] ). Overall, countries with emissions reduction obligations emit on average less CO 2 than similar countries without emissions reduction obligations – with estimates ranging from 3–50% ( [[#Grunewald--2012|Grunewald and Martínez-Zarzoso 2012]] , 2016). [[#Maamoun--2019|Maamoun (2019)]] estimates that the Kyoto Protocol reduced GHG emissions of Annex B countries by 7% on average below a no-Kyoto scenario between 2005 and 2012. [[#Aichele--2013|Aichele and Felbermayr (2013)]] conclude that Kyoto reduced CO 2 and GHG emissions by 10% compared to the counterfactual. By contrast, [[#Almer--2017|Almer and Winkler (2017)]] find no evidence for binding emission targets under Kyoto inducing significant and lasting emissions reductions for any of the Annex B or non-Annex B countries. The authors identify both negative and positive associations between Kyoto and emissions for several countries in several years, but no coherent picture emerges. [[#Hartl--2019|Hartl (2019)]] calculates a Kyoto leakage share in global CO 2 trade of 4.3% for 2002–2009.

In terms of transformative potential, the Kyoto Protocol has been found to increase international patent applications for renewable energy technologies, especially in the case of solar energy technologies and especially in countries with more stringent emissions reduction targets, and has even led to an increase in patent applications in developing countries not obliged to reduce emissions under Kyoto ( [[#Miyamoto--2019|Miyamoto and Takeuchi 2019]] ). Kyoto also had a positive and statistically significant impact on the cost-effectiveness of renewable energy projects, as well as renewable energy capacity development, as it stimulated the introduction of domestic renewable energy policies ( [[#Liu--2019|Liu et al. 2019]] ).

The issue of institutional strength of Kyoto has been analysed by many authors, and much of this has been assessed in previous assessment reports. Since AR5, several papers question the environmental efficacy of the Kyoto Protocol based on its institutional design ( [[#Rosen--2015|Rosen 2015]] ; [[#Kuriyama--2018|Kuriyama and Abe 2018]] ). Particular attention has focused on Kyoto’s market mechanisms ( [[#Erickson--2014|Erickson et al. 2014]] ; [[#Kollmuss--2015|Kollmuss et al. 2015]] ).

As described in previous IPCC reports and above, the 1997 Kyoto Protocol included three international market-based mechanisms. These operated among Annex I Parties (i.e., International Emissions Trading and Joint Implementation) and between Annex I Parties and non-Annex I countries (i.e., the CDM) ( [[#Grubb--2014|Grubb et al. 2014]] ; [[#World%20Bank--2018|World Bank 2018]] ). Joint Implementation led to limited volumes of emissions credit transactions, mostly from economies in transition but also some Western European countries; International Emissions Trading also led only to limited transaction volumes ( [[#Shishlov--2016|Shishlov et al. 2016]] ).

Of the Kyoto Protocol’s mechanisms, the CDM market has led to a greater amount of activity, with a ‘gold rush’ period between 2005 and 2012. The main buyers of CDM credits were private companies surrendering them within the European Union (EU) Emissions Trading System (ETS). Once the EU tightened its rules and restricted the use of CDM credits in 2011, there was a sharp drop in the price of CDM credits in 2012. This price never recovered, as the demand for CDM was very weak after 2012, in part because of the difficulties encountered in securing the entry into force of the Doha Amendment ( [[#Michaelowa--2019b|Michaelowa et al. 2019b]] ).

Assessing the effectiveness of Kyoto’s market mechanisms is challenging, and the results have been mixed ( [[#Aichele--2013|Aichele and Felbermayr 2013]] ; [[#Iwata--2014|Iwata and Okada 2014]] ; [[#Kuriyama--2018|Kuriyama and Abe 2018]] ). [[#Kuriyama--2018|Kuriyama and Abe (2018)]] assessed emissions reduction quantities taking into account heightened criteria for additionality. They identified annual energy-related emissions reductions of 49 MtCO 2 -eq yr –1 flowing from the CDM, and non-energy related emissions reductions of 177 MtCO 2 -eq yr –1 . Others have pointed to issues associated with non-energy related emissions reductions that suggest the latter estimate may be of questionable reliability, while also noting that regulatory tightening led later CDM projects to perform better with respect to the additionality criterion ( [[#Michaelowa--2019b|Michaelowa et al. 2019b]] ). The CDM’s contribution to capacity building in some developing countries has been identified as possibly its most important achievement ( [[#Spalding-Fecher--2012|Spalding-Fecher et al. 2012]] ; [[#Gandenberger--2015|Gandenberger et al. 2015]] ; [[#Murata--2016|Murata et al. 2016]] ; [[#Xu--2016|Xu et al. 2016]] ; [[#Dong--2017|Dong and Holm Olsen 2017]] ; [[#Lindberg--2018|Lindberg et al. 2018]] ). There is evidence that the CDM lowered compliance costs for Annex 1 countries by at least USD3.6 billion ( [[#Spalding-Fecher--2012|Spalding-Fecher et al. 2012]] ). In host countries, the CDM led to the establishment of national approval bodies and the development of an ecosystem of consultants and auditors ( [[#Michaelowa--2019b|Michaelowa et al. 2019b]] ).

On the negative side, there are numerous findings that the CDM, especially at first, failed to lead to additional emissions cuts in host countries, meaning that the overall effect of CDM projects was to raise global emissions. [[#Cames--2016|Cames et al. (2016)]] concluded that over 70% of CDM projects led to emissions reductions that were likely less than projected, including the absence of additional reductions, while only 7% of projects led to actual additional emissions reductions that had a high likelihood of meeting or exceeding the ''ex-ante'' estimates. The primary reason the authors gave was associated with the low price for CDM credits; this meant that the contribution of the CDM to project finance was negligible, suggesting that most CDM projects would have been built anyway. A meta-analysis of ''ex-post'' studies of global carbon markets, which include the CDM, found net combined effects on emissions to be negligible ( [[#Green--2021|Green 2021]] ). Across the board, CDM projects have been criticised for lack of ‘additionality’, problems of baseline determination, uneven geographic coverage ( [[#Michaelowa--2011a|Michaelowa and Michaelowa 2011a]] ; [[#Cames--2016|Cames et al. 2016]] ; [[#Michaelowa--2019b|Michaelowa et al. 2019b]] ), as well as failing to address human rights concerns ( [[#Schade--2014|Schade and Obergassel 2014]] ).

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