Japan

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Critically Insufficient4°C+ World

NDCs with this rating fall well outside of a country’s “fair share” range and are not at all consistent with holding warming to below 2°C let alone with the Paris Agreement’s stronger 1.5°C limit. If all government NDCs were in this range, warming would exceed 4°C. For sectors, the rating indicates that the target is consistent with warming of greater than 4°C if all other sectors were to follow the same approach.

Highly insufficient< 4°C World

NDCs with this rating fall outside of a country’s “fair share” range and are not at all consistent with holding warming to below 2°C let alone with the Paris Agreement’s stronger 1.5°C limit. If all government NDCs were in this range, warming would reach between 3°C and 4°C. For sectors, the rating indicates that the target is consistent with warming between 3°C and 4°C if all other sectors were to follow the same approach.

Insufficient< 3°C World

NDCs with this rating are in the least stringent part of a country’s “fair share” range and not consistent with holding warming below 2°C let alone with the Paris Agreement’s stronger 1.5°C limit. If all government NDCs were in this range, warming would reach over 2°C and up to 3°C. For sectors, the rating indicates that the target is consistent with warming over 2°C and up to 3°C if all other sectors were to follow the same approach.

2°C Compatible< 2°C World

NDCs with this rating are consistent with the 2009 Copenhagen 2°C goal and therefore fall within a country’s “fair share” range, but are not fully consistent with the Paris Agreement long term temperature goal. If all government NDCs were in this range, warming could be held below, but not well below, 2°C and still be too high to be consistent with the Paris Agreement 1.5°C limit. For sectors, the rating indicates that the target is consistent with holding warming below, but not well below, 2°C if all other sectors were to follow the same approach.

1.5°C Paris Agreement Compatible< 1.5°C World

This rating indicates that a government’s NDCs in the most stringent part of its “fair share” range: it is consistent with the Paris Agreement’s 1.5°C limit. For sectors, the rating indicates that the target is consistent with the Paris Agreement’s 1.5°C limit.

Role model<< 1.5°C World

This rating indicates that a government’s NDC is more ambitious than what is considered a “fair” contribution: it is more than consistent with the Paris Agreement’s 1.5°C limit. No “role model” rating has been developed for the sectors.

1.5°C Compatible< 1.5°C World

Historical data

For historical data, we use data submitted via the Common Reporting Format 2018 (UNFCCC, 2018b).

Pledges and targets

2020 pledge

Target emission level for 2020 were calculated from 2005 emission data according to Japan’s Second Biennial Report to the UNFCCC (Government of Japan, 2015). We calculated Japan's LULUCF accounting quantities in 2020 for afforestation, reforestation and deforestation based on the accounting rule under the second commitment period of the Kyoto Protocol. Net removal by forests (38 MtCO2e/yr) is taken into account for 2020.

NDC

The target for 2030 was calculated using Japan’s NDC and the UNFCCC CRF data submitted in 2018 (UNFCCC, 2018b). Because of this, the NDC emission level excluding LULUCF quantified in this analysis (1078 MtCO2e/yr) is slightly different from the one in the NDC document (1079 MtCO2e/yr).

Current policy projections

Energy-related CO2 emissions

Japan’s Third Biennial Report (Government of Japan, 2017) only provides “With measures” emissions projection, which is the NDC achievement scenario taking into account not only the policy measures already implemented in FY2013 but also those to be implemented by FY2030. The assumed GDP growth rates are also very high—on average 1.7% per year for 2013-2030 based on the government's growth target (METI, 2015).

For the analysis of current policy projections, we used the IEA World Energy Outlook (WEO) 2018 Current Policies Scenario (IEA, 2018b), which covers various climate related policies implemented as of mid-2017 and their impact on energy-related CO2 emissions as a basis. The GDP for 2030 assumed in the IEA WEO 2018, based on World Bank and International Monetary Fund estimates, is 16% lower than that assumed in the NDC.

The WEO foresees a relatively large share of nuclear energy plants in electricity generation for 2030 (17%). While this is overachieved by the current assumptions of the government (Basic Energy Plan), it is not completely supported by the rate of restart of currently shut down nuclear power plants. We explored “high nuclear” and “limited nuclear” scenarios:

For the full nuclear restart scenario, it is assumed that all 25 nuclear reactors (plus two allowed to resume construction) that applied for restart as of September 2018 will be approved and complete their extended 60-year lifetime (with an average 6500 hours/yr operation, comparable to about 6400 hours/yr assumed in IEA WEO 2018’s Current Policies Scenario). For the two reactors in construction, the Ohma reactor is assumed to start operation in 2026 and the Shimane no.3 reactor in 2020. The changes in nuclear power generation compared to the IEA WEO 2018’s Current Policies Scenario is balanced by coal and gas power. The ratio of coal and gas power converges to 1:1 by 2030 and the average capacity factor of nuclear power plants was assumed to be 80%.

For the limited nuclear scenario, it is assumed that only 14 reactors that are allowed to restart as of September 2018 after additional safety measures were implemented would be in operation up to 2030 (some with a 60-year extended lifetime) but at a much shorter 3250 hours/yr operation on average, taking into account the possible court cases and unplanned inspections. The electricity supply gap is filled by renewables and fossil fuel power (coal and gas power)—the ratio between renewables and fossil fuel power remains the same as in IEA WEO 2018 and the ratio between coal and gas power converges to 1:1 by 2030.

After the recalculation of the 2030 electricity mix, CO2 emissions were recalculated— CO2 emission factors per technology were assumed to be identical to those in the WEO 2018 CPS. Finally, the growth rates of energy-related CO2 emissions up to 2030 recalculated based on the IEA WEO 2018 CPS were applied to the 2016 historical energy related CO2 reported in the national GHG inventory report submitted to the UNFCCC.

Other emissions

For other emissions, the quantification approach has been updated since the last update to account for the recent policy developments, recent trends in F-gas emissions as well as the changes in the GWPs used to express GHG emissions. The projections from the Ministry of the Environment (MOEJ, 2012a) are no longer used—the main reason is that these rather old projections were only available for non-energy CO2 emissions and non-CO2 GHG emissions combined, thus not allowing for revising emission estimates for F-gas emissions taking into account the recent emission trends and recent policy developments.

For the emissions of non-energy CO2, CH4 and N2O, we assumed that the intensity of these emissions per unit GDP will reduce linearly towards 2030 following the historical trends observed between 2010 and 2016. The GDP growth projections up 2030 were taken from IEA (2018b).

For F-gas emissions, the expected impacts of the Act on Rational Use and Proper Management of Fluorocarbons (2013 amendment) to enhance management of F-gas use and the Ozone Layer Protection Act (‘F-gas Act’, 2018 amendment) to regulate production and imports of F-gases to comply with the Kigali Amendment were also considered. Our calculations show that the HFC emission levels to be about 8 MtCO2e/yr higher in 2020 and 22 MtCO2e/yr in 2030 compared to the levels targeted under the NDC (Government of Japan, 2015; MOEJ, 2012b; MOEJ & METI, 2014).

As described in the current policy projections section, the F-gas Act has not been successful in improving the recovery rate of refrigerants from end-of-life refrigeration and air conditioning equipment in 2015 was only 38% (METI & MOEJ, 2017). Based on the historical trends reported in METI and MOEJ (2017), we assume that the HFC recovery rate will not improve over time (40% for 2020-2030). We also assume that the leakage rates for the in-use stock will also not improve under current policies. Regarding the 2018 amendment of the Ozone Layer Protection Act, the business-as-usual consumption levels are projected to be below the Kigali cap at least until 2025 (METI, 2018b); the Kigali cap for Japan becomes significantly lower only in 2029. Since there is some time lag between consumption and emissions, we assume that the amended Ozone Layer Protection Act will not affect the HFC emission levels up to 2030.

The point of departure for the revised F-gas emission projections is the business-as-usual (BAU) projections provided in the background document of the Plan for Global Warming Countermeasures (MOEJ, 2016a)– the Plan projects F-gas emissions to increase from 39 MtCO2e/yr in 2013 to 77 MtCO2e/yr in 2030 under a BAU scenario (expressed in AR4 GWP terms). The three measures: (i) enhanced recovery from end-of-life equipment, (ii) avoidance of leakage from in-use equipment, and (iii) switch to lower GWP F-gas and non-F-gas refrigerants are expected to reduce emissions to the NDC target level of 29 MtCO2e/yr in 2030. In our assessment, we assume that only part of the NDC implementation plan would be achieved, i.e. the switch to lower GWP F-gas and non-F-gas refrigerants. The resulting F-gas emissions projections in 2030 are 66 MtCO2e/yr, which is more than double the NDC target level; the new projections are roughly 20 MtCO2e/yr higher than our previous projections.

Global Warming Potentials

The CAT uses Global Warming Potential (GWP) values from the IPCC's Fourth Assessment Report (AR4) for all its figures and time series. Assessments completed prior to December 2018 (COP24) used GWP values from the Second Assessment Report (SAR).