ALPS International Symposium
Otemachi Sankei-Plaza
February 10, 2016

Evaluations on emission reduction effortsof INDCs and pathways to deep emission
reductions beyond 2030
Keigo AkimotoGroup Leader, Systems Analysis Group
Research Institute of Innovative Technology for the Earth (RITE)

Contents
1. Background and objective
2. Evaluations of NDCs (GHG emission reduction
targets)
3. The relationship between the global emission
estimated from the NDCs and the long-term
temperature goal (2 C/1.5C target), andrequired emission reductions beyond 2030

4. Conclusions

2

Background and objective

Trajectory of Global GHG Emission by Source
4

Source) IPCC AR5, 2014

The global emissions after 2000 increased more rapidly. The Kyoto Protocol was not able
to exert large effects.

Trajectory of Global CO2 Emission by Region
5

Consumption-based
CO2 emissions haveHigh income not decreased even incountries
HIC.
($12,616 and more)

Upper middle income countries($4,086 to $12,615)(China, Brazil, Iran, Malaysia, South
Africa etc.)
Rapid increase in CO2 emissions

Lower middle income countries($1,036 to $4,085)(India, Indonesia, Philippine, Egypt etc.)
Tackling poverty; less priority
to CO2 emission mitigation

Low income countries($1,035 and less)

Source) IPCC AR5, 2014

GHGs Emissions Covered by the Countries in
Kyoto Protocol and Paris Agreement

6

Australia 1.2%

Kyoto Protocol

Kazakhstan 0.7%
Other KP nations 1.4%
(The first commitment period)

Japan 2.8%
Russia 5.1%
OthersCanada 1.5%

(The second commitment period)
US

The agreement of participations by
all countries (post-2020 framework)
159 nations and 1 regions that havesubmitted their NDCs by Dec. 14.
(over 95% of global GHG emissions)

India

China

Emission share in 2010

Source: METI

Background and objectives of ALPS projectand its major topics

7

Climate change is a very complex issue. Effectiveness of response measures in the realworld are important. The aim of the ALPS project is to support the developments ofinternational frameworks to achieve green growth and effective response measuresthrough better understandings of technologies, economics, policies etc. and quantitative
analyses and evaluations.
【major topics】
 Risk management strategy for climate change responses- Estimates of climate change damages, adaptations, and mitigation costs and theiruncertainties- Long-term target and the corresponding emission pathways- Risk management strategy for climate change responses under uncertainties etc.


Better economic understandings and analysis for real green growth- Considering the possibilities and limitations of removing energy saving barriers,
relationship between climate change and air pollution mitigation, etc., and model analyses- Estimations of international energy productivity gaps (comparisons between the U.S. and Japan)
competitiveness and green growth- Analyses for international constraint for funding to coal poweretc.



Climate change mitigation measures, particularly the systems measures.
- hydrogen systems (total systems including supply, transport, consumption)- systems of building, and transportationsetc.



Analyses regarding international frameworks, discussions and policy interests- Evaluations of post-2020 emission reduction targets of NDCs
- Contributions to international model comparison projects
etc.

The Paris Agreement
 Submissions of NDCs and Reviews  “Each party shall prepare […] nationally determined contributions

that intends to achieve.” (Article 4 Paragraph 2); “Each Party shallcommunicate a nationally determined contribution every five years”(Article 4 Paragraph 9).
 “Each Party’s successive nationally determined contribution will
represent a progression beyond the Party’s then current nationallydetermined contribution” (Article 4 Paragraph 3).
 However, the Paris Agreement does not specify each country’s GHG
emissions reductions target (one of the major differences with the
Kyoto Protocol).
 In order to ensure an effective implementation, transparency isenhanced: all Parties’ implementation progress is shared andreviewed with flexibility (Article 13).

Appropriate reviews for the NDCS in the Paris Agreement processes
are important in order to make worldwide effective GHG emission
reductions.

8

The Paris Agreement
 Long-term Targets 9 “To hold the increase in the global average temperature to well below 2 C above

pre-industrial levels and to pursue efforts to limit the temperature increase to 1.5
C above pre-industrial levels” (Article 2, Paragraph 1(a) (According to the
COP21 Decision, IPCC is invited to write “a special report in 2018 on the impactsof global warming of 1.5 C above pre-industrial levels and related global
greenhouse gas emission pathways”)
 “In order to achieve the long-term temperature goal set out in Article 2, Parties

aim to reach global peaking of greenhouse gas emissions as soon as possible,[…] and to undertake rapid reductions thereafter in accordance with best
available science, so as to achieve a balance between anthropogenic emissions
by sources and removals by sinks of greenhouse gases in the second half of
this century”(Article 4, Paragraph 1)
 All Parties should strive to formulate and communicate long-term low

greenhouse gas emission development strategies (Article 4 Paragraph 19) (andthe time horizon was clarified until 2020 according to the COP21 Decision) In order to assess the world’s progress towards the Agreement’s goal and long-term targets, the state of implementation will be examined every 5 years.
(”Global stocktake”, first time in 2023)
 Besides, major economies announced the initiative by private and public sectors

for research and development of clean energies “Mission innovation”.

Evaluations of NDCs (GHG
emission reduction targets)Principals of Indicators for Measuring
Fair and Equitable Emission Reduction Efforts
Aldy & Pizer (2014) pointed out the importance ofreviewing each country’s pledge in terms of emissions
reductions:

The metrics used for the comparative analysis of countries’
emissions reduction efforts have to comply with thefollowing principles:- Comprehensive: in order to capture the entire effort undertaken- Measureable: direct or indirect measurement possible- Replicable: transparent enough as to be easily replicated- Universal: applicable to as broad a set of countries as possible

There is no unique indicator to rate the fairness and equity ofemissions reduction efforts. It is thus important to adopt a
multifaceted approach using a number of relevant indicators.

Aldy & Pizer, Comparability of Effort in International Climate Policy Architecture, Harvard Kennedy School (2014)11

How to measure the comparability of efforts

12

The submitted INDCs include the targets of emissions reduction fromdifferent base years, CO2 intensity, and CO2 emission reductions
from baseline (w/w.o. clear definition of baseline). We need tointerpret them through comparable metrics to measure the efforts:
Simple metrics (easily measurable and replicable)- Emissions from the same base yearetc.

More advanced metrics (more comprehensive, but require
forecasts)- Emission reduction ratios from baseline emissions- Emissions per unit of GDP
etc.



Most advanced metrics (most comprehensive, but require
modeling)- Energy price impacts- Marginal abatement cost (per ton of CO2)
- Abatement costs as a share of GDP
etc.

Employed indicators for measuring emissions
reduction efforts (1/2)
Emissions reduction
efforts evaluation method

Framework

Notes

Emissions
reduction ratio
from base year
(only for OECD
countries orAnnex I countries)

When baseline emissions are expected
to stagnate, it is more relevant to simply
compare the projected reduction rates(all the more since there areuncertainties regarding the BAU). This
is why we use the reduction ratio
compared to BAU for OECD countries
only - on the other hand, such an
approach would be irrelevant for
countries where emissions are
expected to grow substantially.

Most countries use 2005 as theirbase year (as a matter of fact, 1990
seems too far in the past to be used
as a base year to evaluate theemissions reduction effort forupcoming emissions)Compared to2005

Compared to2012 (or 2010)13

This seems a relatively good choice
to evaluate future efforts as it allows
assessing reduction ratios incomparison with recent
circumstances.

Emissions per
capita (only for
non-OECD
countries or nonAnnex I countries)

Absolute value

For OECD countries, we adopt the
reduction ratio from base year insteadof the absolute value of emissions per
capita.

As it is highly dependent on the
country’s level of economic activity
and situation in general, it can bedifficult to assess emissions reduction
efforts through this indicator.

CO2 intensity(GHG emissions
per GDP)

Absolute value

Reveals what level of CO2 emissions
corresponds to what degree of
economic activity

It can easily reach bad values forcountries with a low GDP; it is also
highly dependent on the country’s
industry structure.

Improvement
rate(compared to2012 or 2010)

As it removes the bias due to the factthat economic growth has changed
compared to the base year, it reveals
the real effort in emission reduction.

For countries with a low GDP, carbon
intensity can improve greatly just due
to high economic growth.

Employed indicators for measuring emissions
reduction efforts (2/2)

14

Emissions reduction efforts
evaluation method

Framework

Notes

Emissions
reduction ratio
compared to BAU

It allows taking into account thedifference of economic growths, etc.

It puts aside past efforts inenergy savings and abatement
potential of renewables.

CO2 marginal
abatement cost(carbon price)

This is a particularly relevant
indicator to assess reduction efforts
as it contains countries’ differences interms of economic growth, energy
savings efforts, abatement potentialof renewables.

Past measures such as taxes onenergy are out of the scope(however, one must keep in mind
that, as energy savings efforts
have already been made in thepast, this may lead to higher
estimates of marginal abatement
costs.)

While marginal abatement costs
show the additional effort to be made,this indicator also includes the efforts
made in the baseline.

Market data is available for expost evaluation, but for ex-anteevaluation, only model-based
estimates are available whichmakes uncertainties rather high.

As marginal abatement costs do nottake into account the economy’s
ability to bear such an effort, thisindicator does.

Uncertainties are high as this is amodel-based estimation.

Retail prices ofenergy(electricity, citygas, gasoline,
diesel)Emission
reduction costs
per GDP

Weighted
average ofhistorical datafrom 2012 or2010

Evaluated INDCs (1/2)
The 119 INDCs submitted as of October 1st, 2015 were evaluated.
As of October 1st, 2015, 119 INDCs had been submitted, and representing
about 88 per cent of global emissions in 2010.
Comprehensive evaluations of emission reduction efforts were only for 20
countries (see below) due to the limited regional resolution of the model.
2020 (Cancun Agreements)

Post-2020 (INDCs)

United States-17% compared to 2005-26% to -28% by 2025 compared to 2005

Canada-17% compared to 2005-30% by 2030 compared to 2005

EU28

-20% compared to 1990-40% by 2030 compared to 1990

Switzerland-20% compared to 1990

-50% by 2030 compared to 1990（-35% by 2025 compared to 1990）

Norway-30% compared to 1990-40% by 2030 compared to 1990Japan

-3.8% compared to 2005*-26% by 2030 compared to 2013

Australia-5% compared to 2000

-26% to -28% by 2030 compared to 2005

New Zealand-5% compared to 1990-30% by 2030 compared to 2005

Russia-15 to -25% compared to 1990-25% to -30% by 2030 compared to 1990

Note: More ambitious emission reduction targets had been submitted as “conditional “ targets from some countries,
but they are not included in this table.
* Emission reduction target assuming zero nuclear power

15

Evaluated INDCs (2/2)
162020 (Cancun Agreements)

Post-2020 (INDCs)

Non-EU Eastern
Europe―-19% by 2030 compared to 1990*

Ukraine-20% compared to 1990-40% by 2030 compared to BAU

Belarus-5 to -10% compared to 1990-28% by 2030 compared to 1990

Kazakhstan-15% compared to 1992-15% by 2030 compared to 1990

Turkey―-21% by 2030 compared to BAU

Korea-30% compared to BAU-37% by 2030 compared to BAU

Mexico-30% compared to BAU-25% by 2030 compared to BAU**(-22% by 2030 compared to BAU in GHG)

South Africa-34% compared to BAU

614MtCO2eq/yr by 2030

Thailand-7 to -20% compared to BAU(Energy and transportation sectors)-20% by 2030 compared to BAU

China

To reduce CO2/GDP by-40 to -45% compared to 2005

To reduce CO2/GDP by -60 to -65% by2030 compared to 2005 (To achieve thepeaking of CO2 emissions around 2030
and making best efforts to peak early)

India

To reduce GHG/GDP by-20 to -25% compared to 2005

To reduce GHG/GDP by -33 to -35% by2030 compared to 2005

* The reduction rate was estimated from the total emissions by the INDCs of Albania, Makedonia, Moldova, and Serbia.
** Emission reduction target of Mexico includes black carbon.

International comparison of emission reduction ratiosfrom the base year of 2005
Switzerland
NorwayEU28
CanadaNew ZealandUnited States
Australia
Japan
Korea
RussiaEast Europe(Non-EU
countries)
Europe(Non-EU
countries)
Belarus
Kazakhstan
ThailandUkraineMexicoSouth Af rica
China
Turkey
India
300

-51.6
-44.5
-34.8
-30.0
-30.0
-27.0
-26.0
-25.4

17

larger

-5.3
14.2
15.6
19.0
19.7
30.1
32.2
32.8
38.2
116.9
180.9

smaller

235.4

250

200

150

100

50

0

-50

-100

GHG emission compared to base year (2005) (%)* The average values are shown for the countries submitted the INDC with the upper and lower ranges.

Note) This indicator was employed only for OECD countries or Annex I countries for the integrated ranking.

International comparison of
GHG emissions per capita
Switzerland
India
Europe(Non-EU
EastEast
Europe(Non-EU
countries)…
NorwayMexicoThailand
EU28
Japan
TurkeyNew Zealand
Korea
South Af rica
China
BelarusCanadaUkraineAustralia
United States
Kazakhstan
Russia0

18

3.1

larger

4.7
5.1
5.5
5.7
6.2
6.6
8.9

10.8
10.9
10.9
11.0
11.8
11.8
12.8
13.9
14.5
15.0

17.2

5

10

15

18.5 smaller

20

GHG emission per capita (tCO2eq/capita)* The average values are shown for the countries submitted the INDC with the upper and lower ranges.

Note) This indicator was employed only for Non-OECD countries and Non-Annex I countries for the integrated ranking.

International comparison of
GHG emissions per GDP (MER)
Switzerland
NorwayJapan
EU28
United States
CanadaAustralia
New Zealand
Korea
MexicoTurkeyEast
Europe(Non-EU
countries)…
East
Europe(Non-EU
ThailandRussiaChina
South Af rica
Belarus
Kazakhstan
India
Ukraine
0

19

0.05
0.07
0.16
0.18
0.27
0.28
0.29
0.31
0.32
0.43

larger

0.83
0.89
0.92
0.94
1.13
1.17
1.21
1.37
1.62
2.67

0.5

1

1.5

2

2.5

GHG emission per GDP (kgCO2eq/$2005)* The average values are shown for the countries submitted the INDC with the upper and lower ranges.

smaller3International comparison ofchange in CO2 intensity (GHG/GDP)

20

-5.5

Kazakhstan
RussiaSwitzerland
NorwayChina
Australia
United States
New Zealand
CanadaThailand
Korea
Japan
EU28
Belarus
UkraineEast (Non-EU
Europe(Non-EU
countries)
urope
countries)
MexicoSouth Af rica
India
Turkeylarger

-5.1
-5.0
-4.8

-4.2
-4.0
-4.0
-3.8
-3.6
-3.5
-3.4
-3.3
-3.0
-2.7
-2.5
-2.4
-1.9
-1.8
-1.6

smaller

0.7

2

1

0

-1

-2

-3

-4

-5

Change in CO2 intensity (GHG/GDP) (%/yr)* The average values are shown for the countries submitted the INDC with the upper and lower ranges.

-6International comparison of emissions reduction
ratio compared to BAU (Baseline)-54.4

Switzerland
NorwayThailandKorea
New ZealandAustralia
CanadaEU28
United StatesJapan
Kazakhstan
MexicoEastEurope(Non-EU
countries)
Europe (Non-EU countries)
South Af rica
Belarus
RussiaChina
India
Ukraine 33.2
Turkey 33.3
40

21

-46.2
-42.8
-41.0
-40.1
-38.7
-38.5
-38.0

larger

-30.8
-25.9
-25.1
-24.8
-24.2
-15.7
-15.4
-9.6
-3.8
0.3

smaller
30

20

10

0

-10

-20

-30

-40

GHG emission compared to BAU (%)* The average values are shown for the countries submitted the INDC with the upper and lower ranges.

-50

-60

International comparison of
CO2 marginal abatement costs
Switzerland
Japan
EU28
CanadaKorea
New ZealandUnited States
NorwayEast
Europe(Non-EU
countries)…
East
Europe(Non-EU
Thailand33
Australia
27
Mexico14
Kazakhstan
12
Belarus4
Russia1South Af rica0
Turkey0India
0Ukraine
0
China
0

50

22

380
378

larger

210
166
144

95
85
70
58
54

smaller
100

150

200

250

300

350

CO2 marginal abatement cost ($/tCO2)* The average values are shown for the countries submitted the INDC with the upper and lower ranges.

400International comparison ofretail prices of energy (electricity)
EU28
Japan
Switzerland
Australia
New ZealandTurkeyUnited States
East
Europe(Non-EU
countries)…
East
Europe(Non-EU
ThailandBelarus
MexicoCanadaChina
NorwayKazakhstan
South Af rica
Korea
Ukraine
India
Russia
0

23

35.8

33.9

larger

27.7
24.2
23.5
15.9
15.9
15
13.5
12.3
11.4
11.0
10.5
8.6
8.4
7.7
5.6
5.4
5.2

smaller

1.8

5

10

15

20

25

30

35

Electricity (household) price（UScent/kWh）* The average values are shown for the countries submitted the INDC with the upper and lower ranges.

40International comparison ofemission reduction costs per GDP
Australia
UkraineThailand
New Zealand
East
Europe(Non-EU
countries)
East
Europe(Non-EU…
Switzerland
Korea
EU28
Japan
CanadaUnited States
South Af rica
MexicoBelarus
0.0
Russia0.0
Turkey
0.0
India
0.0
Kazakhstan
0.0
China
0.0
Norway
0

24

2.4
1.8

larger

1.4
1.1
1.0
1.0
0.8
0.8
0.6
0.5
0.4
0.3
0.3
0.2

smaller
0.5

11.5
Emission reduction cost per GDP (%)

2* The average values are shown for the countries submitted the INDC with the upper and lower ranges.

2.5

Ranking index of emissions reduction efforts(ambition) of INDCs by indicator

25

Emissions reduction
ratio from base year/
Emissions per capita
Emission per GDP
Emission reduction
ratio compared to BAU
CO2 marginal
abatement cost
Retail prices of energy
Emission reduction
costs per GDP

The wider the radar chart is, the greater the emission reduction efforts (ambition) are.

Many indicators (excepting emission reduction costs per GDP) of Switzerland and Japan
were evaluated to have high rankings. CO2 marginal abatement cost of Australia is nothigh, but the emission reduction cost per GDP is large.

Marginal abatement costs by two models
26(RITE DNE21+ and FEEM WITCH)
CO2 marginal abatement costs, averaged
costs for 2025-30 (US$2005/tCO2)

160
140
120
100
80

USG Social Cost of
Carbon (SCC):
53$/tCO2 for 2025-30

60
40
20
0
WITCH DNE21+ WITCH DNE21+ WITCH DNE21+ WITCH DNE21+ WITCH DNE21+
USA

EU

China

India

Marginal abatement
costs if theaggregated INDCs
are achieved mostcost- efficiently:
16$/tCO2 by WITCH,
6$/tCO2 by DNE21+

Korea/S.Africa/Australia

Source: B. Pizer, J. Aldy, R. Kopp, K. Akimoto, F. Sano, M. Tavoni- The marginal abatement costs vary across models for some countries, but are comparable for many
countries/regions.
- The CO2 marginal abatement costs of the INDCs of OECD countries are much higher than the marginal
cost that is estimated assuming that the total reductions are achieved most cost-efficiently (globally
uniform marginal abatement cost).

The relationship between the
global emission estimated fromthe NDCs and the long-term
temperature goal (2 C/1.5Ctarget), and required emission
reductions beyond 2030

GHG emission outlook of NDCs (UNFCCC estimate)
28

INDC Synthesis Report of UNFCCC

http://unfccc.int/focus/indc_portal/items/9240.php
Based on the submissions made on 2015,
October 1st, by 119 countries

56.7 (53.1～58.6) GtCO2eq

P3
P1
P2

P1: immediately reduced from 2010 level to +2 C target (>66% achievability)
P2: reduced after Cancun Pledge to +2 C target (>66% achievability)
P3: reduced after 2030 NDCs to +2 C target
There are wide gap between P2 (also P1) and P3. However, there remains pathways to reach +2 C target(>50%) after 2030 NDCs by deepening emission reductions thereafter.

Expected global GHG emissions of the aggregated INDCs andthe corresponding emission pathways up to 2100 toward +2 C goal

29

GHG emissions (GtCO2-eq./yr)

200

Marginal abatement cost under the least cost measures
150

About 6$/tCO2 in 2030 for the achievement of the
expected global emission reductions by INDCs

About 70$/tCO2 in 2050

Baseline emissions reported
in the IPCC AR5

It is important to induce the achievements of
INDCs and further emission reductions forcountries having room for more reductions
through PDCA (plan-do-check-act) cycle.

100

It is important to seek deeper emission
reductions through developments anddeployments of innovative technologies.

50

around +2.5 to 3ºC
around +2 to 2.5ºC
below +2ºC

About 320$/tCO2 in 2050
0
1990

2000

2010

2020

2030

2040

2050

2060

Historical emissions

2070

2080

2090

2100

Source) Estimate by RITE

Emission outlook under current policies+2.5 ºC stabilization under climate sensitivity of 2.5 ºC (around +2.6 ºC in 2100 and +3.0 ºC in 2200 under C.S. of 3.0 ºC）+2 ºC stabilization under climate sensitivity of 2.5 ºC; temporary overshoot of 580 ppm (+2.5 ºC stabilization under C.S. of 3.0 ºC)
Below +2 ºC in 2100 under climate sensitivity of 3.0 ºC; temporary overshoot of 530 ppm+2 ºC stabilization under climate sensitivity of 3.0 ºC; temporary overshoot of 500 ppm and around 450 ppm in 2300
INDC submitted by October 1 (119 countries) assumed to be implemented- The expected global GHG emission in 2030 is about 59.5 GtCO 2eq. when all the submitted INDCs are successfully achieved.
Emissions reductions from the baseline are estimated to be about 6.4 GtCO 2eq, in which about 0.5 GtCO2eq reductions are offset due
to carbon leakages from nations with INDCs of high marginal abatement costs to those with zero or low costs through induced lower
fossil fuel prices.
- The expected temperature change in 2100 is +2 to +3 C from preindustrial levels. The range depends on the uncertainties of climate
sensitivity, and on future deep emission reductions through developments and deployments of innovative technologies.

Emission reduction costs by INDCs- Comparison between the individual achievement by each country/region
and the global least cost -30

120
Emission reduction costs rise compared withbaseline (billion US$ (in 2000 price)/year)

Costs of INDCs achieved by each country/region

100
The least costs of the expected global emissions byaggregated INDCs (globaly uniform marginal cost of 6$/tCO2)

80
60

40
20
0
United States

EU28

Japan

FUSSR

Korea

China

-20
-40
Source) Estimate by RITE

- Due to large differences in marginal abatement costs across countries, we observe on the one handsevere economic impacts for some countries with high marginal abatement costs for the INDCs, and on
the other hand positive impacts for countries with zero or low marginal abatement costs.
- In reality, achieving the INDCs could require much higher costs per country than the global least-costemission reduction as the IPCC scenarios show.

Atmospheric GHG Concentration, Emission Reduction
in 2050, and Expected Temperature Increase
Sub-category<430

Only a limited number of individual model studies have explored levels below 430 ppm CO2eq

450 (430-480)―

500 (480-530)

550 (530-580)(580-650)

Temperaturein 2100 (C,
relative to1850-1900)

Probability of exceeding thetemperature rise over 21st
century (relative to 1850-1900)

Category byconcentrationin 2100 (ppm
CO2eq)

RCPs

Global GHG
emissions in
2050 (relative
to 2010)31

1.5 C2.0 C3.0 C

RCP2.6 -72-41%

1.51.7C(1.02.8)

49-86%

12-37%

1-3%-57-42%1.71.9C(1.22.9)

80-87%

32-40%

3-4%-55-25%

1.82.0C(1.23.3)

88-96%

39-61%

4-10%-47-19%2.02.2C(1.43.6)

93-95%

54-70%

8-13%

95-99%

66-84%

8-19%

96-100%74-93%

14-35%

99-100%88-95%

26-43%

No exceedanceof 530 ppm
CO2eq
Exceedance of
530 ppm CO2eq
No exceedanceof 580 ppm
CO2eq
Exceedance of
580 ppm CO2eq-16+7%―-38+24%
RCP4.5(650-720)―-11+17%(720-1000)―

RCP6.0 +18+54%

>1000

―

RCP8.5 +52+95%

2.12.3C(1.43.6)
2.32.6C(1.54.2)
2.62.9C(1.84.5)
3.13.7C(2.15.8)
4.14.8C(2.87.8)

100-100% 97-100% 55-83%
100-100%

100100%92-98%

GHG Emission Pathways for Below +2 C

32

70

+9%

60
GHG emissions [GtCO2eq/yr]

Below +2℃ in 2100 underclimate sensitivity of 2.5℃
(overshoot)
Below +2℃ in 2100 underclimate sensitivity of 3.0℃
(overshoot)+2℃ stabilization under climate
sensitivity of 2.5℃

▲19%

50
40
30

+2℃ stabilization under climate
sensitivity of 3.0℃

▲31%

20

450ppm stabilization▲42%
10
Compared to 2010▲71%

Estimate of INDCs by RITE

0
1990

2010

2030

2050

2070

2090

Source) estimated by RITE using MAGICC and DNE21+- The emission pathways are very different even for a certain level of temperature target, i.e.,
below 2 C, depending on the assumptions of the target year, the achievability, climate
sensitivity uncertainties etc.
- The required emission reduction measures also vary according to these uncertainties evenfor the political decisions of the temperature below 2 C.

CO2 Marginal Abatement Costs for Below +2 C
1690$/tCO2 in 2030; 2794$/tCO2 in 2050

500
CO2 marginal abatement cost [$/tCO2 in US 2000 price]

33

400

Below +2℃ in 2100 underclimate sensitivity of 2.5℃
(overshoot)300

Below +2℃ in 2100 underclimate sensitivity of 3.0℃
(overshoot)+2℃ stabilization underclimate sensitivity of 2.5℃
200
+2℃ stabilization underclimate sensitivity of 3.0℃

100
450ppm stabilization
0
2010

2020

2030

2040

2050

Source) estimated by RITE

- According to the analysis by DNE21+, the mitigation measures with over 1000 $/tCO2 arerequired after 2030 for the stabilization at 450 ppm CO2-eq even if the least global cost measures(the equal marginal abatement costs) are implemented.
- The mitigation measures with over 300$/tCO2 are required even for the 2.0 C stabilization
under climate sensitivity of 3.0 C.
- The mitigation costs for below 2 C with overshoot and climate sensitivity of 2.5 C are muchsmaller than those for 450 ppm CO2-eq and +2 C stabilization under climate sensitivity of 3.0 C.

GHG Emission Pathways for Below +1.5 C

34+1.5℃ stabilization underclimate sensitivity of 2.5℃
1.6

+1.5℃ stabilization underclimate sensitivity of 3.0℃

1.4

+1.5℃ stabilization underclimate sensitivity of 3.4℃

1.2Below +1.5℃ in 2100 underclimate sensitivity of 2.5℃

1Below +1.5℃ in 2100 underclimate sensitivity of 3.0℃

0.8

Below +1.5℃ in 2100 underclimate sensitivity of 3.4℃

0.6
1990

Estimate of INDCs by RITE

60
2040

2090

2140

2190

2240

2290

50

Source) estimated by RITE using MAGICC- The global GHG emissions in 2030 should
be reduced by 85% and 52% relative to 2010
for below 1.5 C with over 66% achievability(corresponding to climate sensitivity of
about 3.4 C) and over 50% achievability.
- The emissions in 2030 should be reduced
by 22% for below 1.5 C in 2100 withovershoot with over 66% achievability.

GHG emissions [GtCO2eq/yr]

Global mean temperature increase relative to 1850-1899 [K]

1.8

40

▲22%
30
20

▲52%

10

▲85%
0
1990

2010

-10

-20

Compared to 2010

2030

2050

2070

2090

CO2 Emission Pathways for Below +2 and +1.5 C
50+2℃ stabilization
under climate
sensitivity of 2.5℃

CO2 emissions [GtCO2/yr]

40

35

Below +2 C+2℃ stabilization
under climate
sensitivity of 3.0℃

30

20Below +2℃ in 2100
under climate
sensitivity of 3.0℃
(overshoot)10

Below +2℃ in 2100
under climate
sensitivity of 2.5℃
(overshoot)

0
2010

2060

2110

2160

2210

2260

Below +1.5 C

-10

50

Source) estimated by RITE

40
CO2 emissions [GtCO2/yr]

In both temperature targets
CO2 emissions in a far future
are almost zero, while these
trajectories are very different.

+1.5℃ stabilization
under climate
sensitivity of 2.5℃
+1.5℃ stabilization
under climate
sensitivity of 3.0℃

30

+1.5℃ stabilization
under climate
sensitivity of 3.4℃

20
10
0
2010
-10
-20
-30

2060

2110

2160

2210

2260

Below +1.5℃ in
2100 under climate
sensitivity of 2.5℃
Below +1.5℃ in
2100 under climate
sensitivity of 3.0℃
Below +1.5℃ in
2100 under climate
sensitivity of 3.4℃

Discussions on the Long-term Goals
including 2 C target (1/2)

36David Victor and Charles F. Kennel, Nature, October 2014


Politically and scientifically, the 2 C goal is wrong-headed. Politically, it has allowed
some governments to pretend that they are taking serious action to mitigate global
warming, when in reality they have achieved almost nothing.

A single index of climate-change risk would be wonderful. Such a thing, however,cannot exist. Instead, a set of indicators is needed to gauge the varied stresses thathumans are placing on the climate system and their possible impacts. A global goal for
average concentrations in 2030 or 2050 must be agreed on and translated into specificemissions and policy efforts, updated periodically.

Oliver Geden（SWP）, Nature, May 2015
The fourth assessment of the IPCC stated that emissions must peak by 2015 to staywithin 2 C of warming; yet the fifth IPCC report, released last year, refers to 2030
emissions levels higher than today’s that are still compatible with this limit, albeit withannual emissions-reduction rates of 6%.

Policy-makers are delighted to hear that despite 20 years of mounting emissions, the 2
C target is still theoretically within reach, ignoring the fine print of the IPCC reports.

 The climate policy mantra — that time is running out for 2 C but we can still make it if

we act now — is a scientific nonsense. Advisers who shy away from saying sosquander their scientific reputations and public trust in climate research.

Discussions on the Long-term Goals
including 2 C target (2/2)

37Jeff Tollefson, Nature, November 2015


Climate modellers have developed dozens of rosy 2 C scenarios over several years, and these fed
into the latest assessment by the IPCC. The panel seeks to be policy-neutral and has neverformally endorsed the 2 C target, but its official message, delivered was clear: the goal isambitious but achievable. Despite broad agreement that the emissions-reduction commitments thatcountries have offered up so far are insufficient, policymakers continue to talk about bending theemissions curve downwards to remain on the path to 2 C.



The 2 C scenarios that define that path seem so optimistic and detached from current politicalrealities. In particular, some researchers have questioned the viability of large-scale bioenergy use
with carbon capture and storage (CCS), on which many models now rely as a relatively cheap way
to provide substantial negative emissions.

Knutti, R.（ETH Zürich）et al. , Nature Geoscience, January 2016



The 2 C warming target is perceived as a universally accepted goal, identified by scientists as asafe limit that avoids dangerous climate change. This perception is incorrect: no scientificassessment has clearly justified or defended the 2 C target as a safe level of warming. Global
temperature is the best climate target quantity, but it is unclear what level can be considered safe.
A meaningful target for limiting warming must be clearly related to what should be achieved. In
addition (i) it needs to be observed with sufficient accuracy, both today and back in the past, (ii) a
robust understanding is required of how humans have affected the level of warming so far and how
we can control it, and (iii) it should be easy to communicate. Global mean surface temperaturelargely meets these requirements, but it does not capture ocean acidification, etc.
Global surface temperature is the indicator that meets most of the requirements for a climate target,
but one potential drawback is that the baseline — pre-industrial conditions — is poorly defined.

Conclusions

Managing Long-term Climate Change Risk

39

 Uncertainties in climate change such as climate sensitivity are still high.
 So far, there are wide gaps between the expected global emissions andthe targets of below 2 C and 1.5 C from pre-industrial levels.

 On the other hand, international political communities agree with the 2 Ctarget politically, despite of several critiques claiming that 2 C is unreal,
leading to wrong recognition and wrong policies.

 The following strategy will be a relatively rational when we recognize thereal world and real politics:
1) Short- and mid-term emission reductions should be conducted to meetthe emission pathways below about 600 ppm CO2eq which still havechances to meet the 2 C goal.
2) Policies and measures for inducing technology innovations should beenhanced. The achievability of 2 C target should be increased throughthese activities, and zero emission societies should be aimed in far future.
3) It seems reasonable that research, at least, on geoengineering approache.g. SRM should be pursued as well as adaptation, preparing for the case ofhigh climate sensitivity and serious climate damages.

Evaluations of NDCs and Toward an Increasein Effectiveness40

 Appropriate review of NDCs are very important in order to increase

effectiveness of NDCs and enhance them for deeper emission reductions.
 In the review, multiple and appropriate indicators should be employed formeasuring the efforts.
 We evaluated ‘emission reduction efforts (degree of ambition)’ of INDCs

from various aspects, using multiple measurable indicators, for thenations who had submitted them before October 1st, 2015.
 Many indicators of Switzerland, Japan and EU were evaluated to rank
high. On the other hand, many indicators of Turkey, Kazakhstan and
China were evaluated to rank low. The US was in the middle. However,this result should be interpreted with care because the US’s target year is2025 while many other nations’ are 2030.
 For several nations such as China and India, marginal abatement costs
were evaluated as zero, meaning their INDCs are to be realized in BAU,
according to our socio-economic scenario. Large differences in marginal
abatement costs across nations induce carbon leakage, damaging theeffectiveness of global emission reduction, and causing a great concern.