August 31, 2007

Stabilization of CO2 Concentrations

Systems Analysis Group
Research Institute of Innovative
Technology for the Earth (RITE)

Introduction♦ Article 2, ‘Objective’ in The United Nations Framework Convention

on Climate Change (UNFCCC), sets a goal of achieving stabilizationof greenhouse gas concentrations, but not the specific level.
♦ To tackle the global warming, long-term efforts are crucial and also

development/diffusion of advanced energy-saving/decarbonization
technologies and transforming the social systems are required.
♦ It is sharing the global specific long-term target that would make bywhen and what technology is required to be developed clear. It is along-term target agreement that would make strategic technology
development/diffusion and social system changes possible.
♦ Once we decide a long-term target, the road map for short-,

medium-term emission reduction naturally could be narrowed down.
Also it would help an agreement on short, medium-term action plans.

Article 2 of the United Nations Framework
Convention on Climate Change, OBJECTIVE
The ultimate objective of this Convention and any related legal
instruments that the Conference of the Parties may adopt is to achieve,in accordance with the relevant provisions of the Convention,
stabilization of greenhouse gas concentrations in the atmosphere at alevel that would prevent dangerous anthropogenic interference with theclimate system. Such a level should be achieved within a time frame
sufficient to allow ecosystem to adapt naturally to climate change, toensure that food production is not threatened and to enable economic
development to proceed in sustainable manner.

What target would confront to this ‘ultimate objective’?
How could it be approached ?

International Trends in Long-term Stabilization（1/3）
EU (January, 2007)♦ Ultra-long-term target: limiting global warming to 2 Celsius♦ Mid and long-term target:- 50% GHG emission reduction by 2050 based on 1990 levels. Given the
differences between developed and developing countries, 80% reduction
by 2050 by developed countries.
- Independently 20% reduction by 2020. 30% reduction, depending on othercountries’ targets

Japan (May, 2007): ”Cool Earth 50”♦

Long-term target: Cutting global GHG emissions by half by 2050
♦ Principles:- Participation of major emitters, including US, China and India- Flexible and diverse framework, with due to considerations to the circumstancesof each country- Compatibility between environmental protection and economic growth♦

Launching a national campaign for achieving the target- Review of the target achievement plan, enhancing the reduction measures inmunicipalities and major business entities, launching a national campaign

International Trends in Long-term Stabilization (2/3)
The United States (May, 2007)♦ Long-term target: Consensus of about 15 major emitters, including

China and India, by the end of 2008
♦ Mid-term target: Setup of mid-term target, with due toconsiderations to the circumstances of each country♦ Action plan:- Sectoral working group (sharing clean technologies and bestpractices)- Stimulating development investments of technologies for clean
energy- Elimination of tariff barriers on environmental technologies

International Trends in Long-term Stabilization (3/3)
G8 Summit Heiligendamm (June 6-8, 2007)♦ Commitment to share challenges in tackling climate change for all
♦
♦

♦

♦

♦
♦

countries
Commitment to approach an optimal combination of energy security andeffective climate protection
Commitment to take urgent and concerted action to stabilize green housegas concentrations at a level that would prevent dangerous anthropogenic
interference with the climate system
In the process involving all major emitters, we will seriously consider thedecisions made by the European Union, Canada and Japan which include
at least a halving of global emissions by 2050.
Commitment to the United Nations Framework Convention on Climate
Change (UNFCCC) and to its objective with our common but differentiatedresponsibilities and respective capabilities
We will call for emerging economies to reduce carbon intensity.
We have agreed that the UN climate process is the appropriate fornegotiating future global action on climate change. It is vital that the major
emitting countries agree on a detailed contribution for a new global
agreement under the UNFCCC by the end of 2008.

Future International Negotiations for Long-term
Stabilization
An international conference against global warming hosted by
the United States♦ Invited countries: EU, France, Germany, Italy, England, Japan,

China, Canada, India, Brazil, Korea, Mexico, Russia, Australia,
Indonesia, South Africa, and United Nations♦ Scheduled to discuss the following themes in Post-Kyoto

Protocol framework- Long-term global target- Mid-term target and strategy by country- Sectoral approach- Acceleration of technology development and deployment♦ The first meeting: September 27-28, 2007

The Background for the EU 2℃ Target♦ Council of the Europe Union in 1996: Global mean temperature increases of

up to 2℃ relative to pre-industrial levels, below 550 ppm CO2 concentrations♦ No scientific backgrounds for the target can be found. It is inferred from the

doubled CO2 concentration relative to pre-industrial levels that 550 ppm wasset as a benchmark in analyses♦ Based on a climate sensitivity of 2.5℃, SOx was once said to have a goodcooling effect, so that SOx 0.5℃ cooling could keep 2℃ even in 550ppm CO2
concentration.
♦ After that, Non-CO2 GHG was learnt to have a good green house gas effect.
♦ Along with this, a new concept, equivalent CO2 concentration emerged.

Originally, 550 ppm should have been the concentration of only CO2, but 550
ppm equivalent CO2 concentration has been crucial to hold that 550 ppm
equates to 2℃ (Environment Minister’s Council, 2005).
♦ On the other hand, as SOx emissions have been notably reduced, the cooling

effect is assessed less than -0.5 ℃ in the future.
♦ With the climate sensitivity upward-adjusted to 3 ℃, hereupon 2 ℃≒350 ppm(CO2 only) is common.

Cool Earth 50: The background for halving relative tothe current level♦♦

Cool Earth 50 proposes that cutting by half from the current level is crucial to curb the GHG
emissions to the same level as the capacity of natural sinks, which is scientifically incorrect.
The capacity of natural sinks varies depending on the CO2 concentrations. The higher theconcentrations are, the larger capacity of natural sinks is, and the lower concentrations, the smaller
capacity.

♦This is why natural sinks cannot be the background for cutting by half from the current level

Projections of anthropogenic
CO2 uptake by process-basedmodels run with IPCC IS92a( -: net uptake, +: net emission)

the left panels: CO2 only
the right panels: CO2 plus
simulated climate change

Source) IPCC WG1 TARThe Targets of EU, Japan from the Viewpoint ofAtmospheric CO2 Concentration Stabilization
16
BAU: IPCC IS92a

Annual CO2 emissions (GtCO2eq.)

14Whatever level CO2 concentration
is eventually stabilized at, it has an
issue with timing but significant
emission reduction is unavoidable.

12
10
8
6
4
2

Emission cut by half in 2050
(from the 1990 level to the current level)

0
-2

EU 2℃

1990 2015 2040 2065 2090 2115 2140 2165 2190 2215 2240 2265 2290
Note) bold solid line: IPCC WG1; thin solid line: WRE (Wigley, Richels, Edmonds)

750 ppm
650 ppm
550 ppm
450 ppm
350 ppmCO2 concentration stabilization is an issue
which could not be well agreed. Here, we
discuss what level is legitimated forconcentration stability and agreeable on a
global scale from the scientific perspective

What level is scientifically legitimated forCO2 concentration stability?

The Ultimate Goal of RITE PHOENIX Project♦ We basically have to approach this issue with CBA (cost-benefit analysis) to utilize limited resources effectively andto pursue global optimality♦ But, we have to consider the specific points of global

warming.








Intersectoral integrations of warming impacts: Based on CBA, wideranging impacts of global warming have to be all converted into money,
which would be impossible.
Interregional damage integrations: CBA aggregates interregional global
warming damage costs converted into the monetary value and calculated.
Damages in small island states, for example, do not cost a bundle to thewhole world, which could not be passed undetected for some people.
Intertemporal integrations: Aggregate warming damage costs of eachtime point are calculated with money conversion. Most of the costs areaggregated using an expedient parameter such as discount rates but theburdens on future generations can be seen in many distinctive ways.
Uncertainty♦ Risk and risk perception have to be considered separately* PHOENIX: Pathways toward Harmony Of Environment, Natural resources and Industry complex

PHOENIX Quantitative Assessments–Warming Impacts and Mitigation♦ Global warming impacts and mitigation are assessed by emission

pathways.
♦ Assessed emission pathways:

Reference case (BAU)
Stabilization of atmospheric CO2 concentration(650ppm, 550ppm, 450ppm)*population and economic growth are in IPCC SRES B2, including
sensitivity analysis of A1FI
♦ Quantitative assessment of warming impacts

Impact of sea level rise on coast, on water resources, agricultural
crops, on health, on land ecosystems,

Assessment Procedures for RITE PHOENIX Project
A. The world total_2100_S550 reference scenario<Assessments of global warming impacts>
Scientificanalyses/
assessment

C. By region_2050, 2100, 2150_S650, S550, S450 reference
scenarios<Assessments of global warming impacts>

1) sea level rise/impacts on coasts
2) impacts on crops 3) impacts on
health 4) terrestrial ecosystems5) THC disruption<Assessments of mitigation costs>-impact events (e.g. WAIS, extreme weather, mountain glacier,arctic sea ice, etc.), in addition to the five items in the left box<Assessments of mitigation costs>-System cost increases calculated by an energy
system model- value-added changes by region and industry, in addition tocost increases

B. S650 and S450 reference scenarios, assessing thesame items as the A above

Expert judges
EJ: the firststep

Q1. pairwise comparisons of relative
importance of mitigation of global
warming impacts (5 items)

Negative impact inmonetary terms/cost

Net cost(= negative number of net benefit)
Mitigation cost

Q2. Health impacts on worth avoiding
health (in monetary terms)

The stabilization level when the total
cost is minimum (the maximum total
benefit) is calculated

EJ: thesecond step

Negative impacts bywarming in monetary terms
l

Ref

l

S650 S550

Q1. The most desirable stabilization level is considered comprehensively
Q2. The reasons why Q1 was answered
Q3. The emphasized items when Q1 was answered

Emission pathways/
stabilization
level
S450
l

Aggregating, analyzing
and summarizing
responses

CO2 Emission Paths for the Estimation
30
Reference

CO2 emission [GtC/yr]

25

S650
S550

20

S450

15
10
5
0
1990 2010 2030 2050 2070 2090 2110 2130 2150 2170 2190
Year

Reference: Based on SRES B2, the emission path is derived from DNE21, considering resources
restrictions by 2200. The original technical parameters of DNE21 are adjusted to berelatively close to the SRES B2 emission path.
Concentration stabilization paths (S650, 550, 450): modified concentration stabilization paths of IPCCWGI to be consistent with the latest statistics

CO2 Concentration and Global Mean
Temperature Rise
CO2 concentration (CO2 only）
1000
S650
800

S550
S450

600

Global mean temperature rise
7

Reference

400

200
1990 2010 2030 2050 2070 2090 2110 2130 2150 2170 2190
Year

Temperature rise relative to thepreindustrial level [℃]

CO2 concentration [ppmv]

Reference

6
5
4

S650
S550
S450

3
2
1

Non-CO2 GHGs is assumed based on SRES B2, in all the cases.
Equilibrium climate sensitivity is estimated 3 degrees celsius

01990 2010 2030 2050 2070 2090 2110 2130 2150 2170 2190
Year

Assessment of Global Warming Impacts
by Concentration Stability Level- Geographical Distribution of Temperature Rise (relative to 1990) –Reference case; 2100~

550 ppm stabilization case; 2100~

♦ Significant temperature rise can be seen in the arctic region.
♦ At 550 ppm stabilization level, the temperature rise is inhibited substantially, but significant temperature rise isinevitable around the Arctic.

Assessment of Global Warming Impacts
by Concentration Stability Level- Geographical Distribution of Precipitation Changes (relative to 1990) –Reference case; 2100~

550 ppm stabilization case; 2100~♦

The precipitation tends to increase largely in the equatorial region♦

The impacts on precipitation changes are not so large between emissions scenarios,
but overall, the precipitation tends grow larger in the reference caseAssessment of Global Warming Impacts
by Concentration Stability Level- Sea level Rise 120
Reference

120

S650

100
Sea level rise (cm)100

Breakdown 140

Sea level rise (cm)

S550
80

S450

60

80

Melting of Antarctic ice sheet
Melting of Greenland ice sheet
Melting of ice cap
Thermal expansion
Total

60
40
20
0
1990
-20

40

2020

2050

2080

2110

2140

2170

2200

20
0
1800
-20

1850

1900

1950

2000 2050
Year

2100

2150

2200

10 million people were flooded bystorm waves in the year of 1990 andabout 90 million people are
estimated to be flooded in 2080 incase of the 38cm sea level rise,even considering the enhancementof protective♦

In the Reference case without any measures for emission reductions, the sea level is estimatedto rise about 110cm in 2200 relative to 1990. In case of 650ppm stabilization, 80cm rise isestimated and in case of 450ppm about 55cm rise.

♦

However, even if the concentration is stabilized, the sea level will continue to rise after 2200.

The annual amount of available water
resources per capita

Assessment of Global Warming Impacts
by Concentration Stability Level- Water Resources (1/2) ♦Water stress is assessed based onwater resources abundance, 1000m3
per capita, per year, which is often used
as one of criteria.

♦

As global warming makes some parts inNorth Africa and East Asia have more
precipitation, water stress is mitigated.

♦

In contrast, some parts in Europe,
Mediterranean coast, South Asia andSouth America have increased water
stress.

No water stress
New water stress

Reducedwater stress

1000[m3/person/yr]

Water stress

Considering
Population change
onlyConsidering
the amount ofwater resources
available

No change inwater stress
Growing
water stress

Mitigatedwater stress

Decreased
Increasedwater stress water stress

Reference

Growing water stress

new water stress

Increased water stress

S450

no change

mitigated water stress

reduced water stress

Decreased water stress

Growing water stress

new water stress

Increased water stressno change

mitigated water stress

reduced water stress

Decreased water stress

2150

3,000
2,500
2,000
1,500
1,000
500
S450

S550

S650

Reference

S450

0
S550

S450

S550

S650

Reference

S450

S550

S650

Reference

S450

S550

0

S650

500

2100

S650

1,000

2050

3,500

Reference

1,500

4,000

S450

2150

S550

2100

S650

2050

Water stress-mitigated
Water stress-reduced

Reference

2,000

Population with decreased water stress (million)

Water stress-grown
Water stress-new

Reference

Population with increased water stress (million)

Assessment of Global Warming Impacts
by Concentration Stability Level- Water Resources (2/2) -♦In terms of water resources, water stress tends to be mitigated, since the wholeworld has more precipitation, as global warming continues.

♦

However, it is required to implement appropriate water management in many cases,
as rainfall sometimes tends to increase intensively.

Assessment of Global Warming Impacts
by Concentration Stability Level- Agricultural Crops (1/3) Changes in wheat productivity potentials in the reference case(relative to 1990)♦

In future developing countries can expect improved productivity and a bit of global
warming would benefit cold regions for wheat growth and increased productivity♦

The United States, European Union and Australia have less productivity potentials.

30

Wheat

20

Increase in potential production(relative to 1990)10♦WGI S450
0
-10
-20
-30
-40
-50

Mainly in developing countries, productivity improvement is expected, so the three
concentration stability scenarios show improvement of wheat production potentials.
However, only the reference scenario shows the substantial reduction of production
potentials in 2150.
Due to population growth, production potentials per capita in four scenarios in 2050,
2100, 2150 are lower than today, though production potentials increase.

WGI S450WGI S550

WGI S650

Reference

2150
WGI S450WGI S550

WGI S650

Reference

2100
WGI S450WGI S550

WGI S650

2050
Reference

2150

Decrease in potential per-capita
production (relative to 1990)♦WGI S550

WGI S650

Reference

WGI S450WGI S650

Reference

WGI S550

2100

Decrease in potential per-capita production (%)

2050

WGI S450WGI S550

WGI S650

0Reference

Increase in potential production (%)

Assessment of Global Warming Impacts
by Concentration Stability Level- Agricultural Crops (2/3) -

60
50

Rice

40
30

Increase in potential production(relative to 1990)

20
10

♦

WGI S450WGI S550

WGI S650

Reference

2150
WGI S450WGI S650

Reference

WGI S450WGI S550

WGI S650

2100
WGI S550

WGI S450

2050
Reference

2150

Decrease in potential per-capita
production (relative to 1990)♦WGI S550

WGI S650

Reference

WGI S450WGI S650

Reference

WGI S550
2100

Decrease in potential per-capita production (%)

2050

WGI S450WGI S550

WGI S650

0Reference

Increase in potential production (%)

Assessment of Global Warming Impacts
by Concentration Stability Level- Agricultural Crops (3/3) -

0

-10

-20

-30

Even the reference scenario in 2150 shows less reduction of production potentials thanwheat because rice grows in warmer climate, which should include consideration ofbreeding and changes of planting seasons. Such adaptation is required for the scenario.
Due to population growth, as well as wheat scenarios, production potentials per capita infour scenarios for 2050, 2100 and 2150 are lower than today, though production
potentials increase.

Assessment of Global Warming Impacts
by Concentration Stability Level- Health (heat stress (circulatory disease, respiratory disease)) The breakdown of the 2150
reference case

Emission path (world)-2.0

Circulaterydiseases causedby the coldness(≧65 yrs old)

-3.0

Circulaterydiseases causedby the coldness(<65 yrs old)

-5.0

China

-4.0

Developed capitalist
countries

B2-S450

B2-S550

B2-S650

B2-Ref

B2-S450

B2-S550

B2-S650

B2-Ref

B2-S450

B2-Ref-15

B2-S550

Caused by heat
Caused by coldness-1.0

Former socialist
Europe-5

Circulaterydiseases causedby the heat(<65 yrs old)

Mid-East ･North Africa

00.0

Latin America

5

Circulaterydiseases causedby the heat(≧65 yrs old)

1.0

Other Asia

10

India

2150

Sub-Sahara Africa

2100

Change in the number of deaths
related to warming (million)

2050

-10

Respiratory
diseases causedby the heat(all ages)

2.0

15

B2-S650

Change in the number of deaths
related to warming (million)

3.0♦

Decrease in deaths caused by cold is expected to be larger than increase in deaths
caused by heat.

♦Less deaths in China and increase of net deaths in sub-Saharan Africa can beassumed in the 2150 reference case by region

Assessment of Global Warming Impacts
by Concentration Stability Level- Health (malaria, dengue)Increase in deaths from malaria and dengue caused by global warming
Change in the number of deaths
related to warming (thousand)

1 20
B2-Reference
B2-S650
B2-S550
B2-S450

1 00
80
60
40

Sub-Saharan Africa is assumed to haveincreased number of death in 2050

20
0
2050

2100

2150

♦

Stabilizing the low concentration level decreases a number of deaths♦

However, the impacts are dominated by the level of economic growth, not by global
warming. With the growth of GDP per capita, Asian regions are expected to be freefrom malaria and dengue, and also all scenarios show that sub-Saharan Africa is notexpected to have increased deaths around 2100.

Assessment of Global Warming Impacts
by Concentration Stability Level- Terrestrial Ecosystems and Marine Acidification Ocean acidification
8.1

14
12
10

Reference
S650
S550
S450

Reference

S650

S550

S450

8

8

pH

Biodiversity loss relative to Y1970 [%]Terrestrial ecosystems:
biodiversity loss

7.9

6
4

7.8

2
7.7

0
Y2050

Y2100

Y2150

Y2050

Y2100

Y2150

♦

In 2150, the reference scenario shows that species might be reduced by 12% caused
by global warming, but in the 450 ppm scenario they might be reduced by less than
6%. Meanwhile, in 2500, biodiversity loss in terrestrial ecosystems is assumed to be
reduced by about 12% caused by factors other than global warming.

♦

With a CO2 concentrations in the atmosphere increased, oceans are more acidified.
In scenarios for 2050 pHs in the water are similar, but among scenarios for 2150 pH
0.2 may result in differenceAssessment of Global Warming Impacts
by Concentration Stabilization Level- the Probability of the Collapse of the Thermohaline Circulation (THC) -Probability of THC collapse (%)

B2-Reference
100
90
80
70
60
50
40

B2-S55030

B2-S650
Murphy(2004)
Annan(2006)
Hegerl(2006)20
10 B2-S450

Source) S. Rahmstorf, Nature, 2002

0
0

500

1000

1500

2000

2500

CO2 Concentration as of 2200♦♦

The collapse of the thermohaline circulation may impact ocean ecosystems as drasticallyas unpredictable
In the reference case without any measures to reduce CO2 emissions, the THC may
collapse with 60-90% probability. But if stabilized at 650ppm, the THC may collapse with
10-20% probability, and at 450ppm the probability is less than 5%.

Assessment of Global Warming Impacts
by Concentration Stability Level- Other Impacts-♦ The collapse of West Antarctic ice sheet (WAIS): If WAIS collapses,

the sea level may rise about 4-6m but potential WAIS collapses in
the 21 century is small.
♦ Forest: While rising CO2 concentration levels and global warming

may increase forest potentials, forest fires and pest increase anddamages may reduce the potentials.
♦ Fisheries: Plankton habitat changes or reductions may have effecton significant changes in fishing grounds.
♦ Tropical cyclones: Although tropical cyclones may form lessfrequently, strong tropical cyclones may have potential to form
more frequently.

Assessment of Mitigation of Global Warming
by Concentration Stability Level (1/2)

100
50
0
Y2050

Y2100

Y2150

2027 sectoral value-added loss
estimated by the DEARS model

Reference

S650

S550

S450

SectorTotal Y2027

150

9
8
7
6
5
4
3
2
1
0
-1

Other
Sectors Y2027

200

EnergySector Y2027

250

abate costs is assumed.)

Service
Sector Y2027

300

Reference
S650
S550
S450

Energyintensive
Sector Y2027

350

Marginal abatement costs of global CO2Emissions estimated by the DNE21
model. (The ideal case to equalize the world marginalGDP loss relative to Reference [%]CO2 shadow price [$/tC]

400♦

Especially in the 450 ppm stabilization case, the marginal abatement cost in 2050 ismuch higher than the other scenarios.

♦

The assessment by the DEARS model which divides sectors in details shows the
rapid tendency toward the large value-added loss in the 450 ppm stabilization case.

Assessment of Mitigation of Global Warming
by Concentration Stability Level (2/2)
Primary energy production [Gtoe/yr]

Primary energy production [Gtoe/yr]

Reference case
40
Photovoltaics
Wind
Hydro & Geoth.
NuclearBiomass
Natural Gas
Crude Oil
Coal

35
30
25
20
15
10
5
0
2000

2025

2050
Year

2075

450 ppm stabilization case

40

Photovoltaics
Wind
Hydro & Geoth.
NuclearBiomass
Natural Gas
Crude Oil
Coal

35
30
25
20
15
10
5
0
2000

2100

4
0
2000

2025

2050
Year

2075

2100

16
12

[GtC/yr]

CCS (Ocean Storage)
CCS (Injection into Deep Saline Aquifer)
CCS (Injection into Depleted Gas Well)
CCS (Enhanced Oil Recovery)
Reforestation
Net Emission

CO2 emissions & reductions

12
8

2050
Year

2075

2100

450 ppm stabilization case

16

[GtC/yr]

CO2 emissions & reductions

Reference case2025

CCS (Ocean Storage)
CCS (Injection into Deep Saline Aquifer)
CCS (Injection into Depleted Gas Well)
CCS (Enhanced Oil Recovery)
Reforestation
Net Emission

8
4
0
2000

2025

2050
Year

2075

2100

Models Used for the Assessment of Mitigation Costs♦ Super long-term assessment of the mitigation strategy (~2150): The DNE21

model







The integrated model consists of the top-down economic module (only one sector of
non-energy) and the bottom-up energy system module.
Optimized dynamic nonlinearity model (maximized consumption utility in the wholeworld)
Assessment period: ~2150
Regions: 10 divisions♦Mid-term assessment of the mitigation strategy (~2150): The DEARS model












The integrated model consists of the top-down economic module and the bottom-up
energy system module.
Optimized dynamic nonlinearity model (maximized consumption utility in the wholeworld)
Assessment period: ~mid-21st century
Regions: 18 divisions
Non-energy industries: 18 industrial sectors
Energy industries: 7 sectors in the primary energy, 4 sectors in the second energy
The economic module specified industrial frameworks, based on the GTAP modeland database
The simplified energy system module, based on the DNE21 model
DNE21: Dynamic New Earth 21
DEARS: Dynamic Energy-economic Analysis model with multi-Regions and multi-Sectors

Value Judgment by Specialists
The first step （estimation results by
CBA simple assessment）

1,500
1,000
500
0
-500
-1,000-1,500-2,000

Ref

S650

S550

S450

Group AGroup B
Group CGroup D
All the repondents

It is estimated that the mostgroups of specialists assume
around 650 ppmv (CO2 only) to be
the recommended concentration
stabilization level
The result of the second step

-2,500First step: estimation

A number of respondents
judged around 550 ppmv
(CO2 only) to berecommended in thesecond step where
impacts except the above
five, impacts every time
point and regional
differences are included.

No. of respondent

Net benefit (Billion US1990$ per year)

2,000

Stabilization level

Second step: Answer

A Domain Considered Important by Specialists andContributing to the Recommended Concentration Stabilization Level

Importance degrees by domain
Degree of importance

5
4
3
2

Intertemporal difference

Regional difference

Permafrost

Arctic sea ice

Greenland ice sheet

Weather extreme

Other industries

Livestock industry

Fishery

Forestry

Ocean acidification

Glacier, ice cap
Warming mitigation cost,
countermeasure
Others

The importance degree is mid-level andhas significant co-relation with theconcentration stabilization level

Human health

Agricultural products

Ecosystem

WAIS
Sea level rise,
impact on coastal area
Water resource

THC

1

Many considered the domain important but has no corelation with the concentration stabilization level

Scientific Assessment of the Recent Climate Change
Stern Review (October, 2006, UK)♦

Urgent! Significant reductions

The costs of damages from business-as-usual would be equivalent to at least 5% and
up to 20% of GDP.
The 450~550 ppmvCO2eq. path would well reduce catastrophic risks.
The costs of removing the most risks, getting to 500~550 ppmvCO2eq. are around 1%
of GDP per year. The costs are much lower than the path without taking actions.
Early and deceive mitigations would have more advantages than the case without
measures, economically.

♦♦♦

IPCC the Fourth Assessment Report: Climate Change 2007（summary
for policy makers, published February ~ April, 2007）
♦
♦
♦
♦
♦
♦

Concentration rises due to anthropogenic activities.
The temperature is more likely to rise than it has
been estimated.
Impacts of global warming are obvious facts.
Impacts of global warming are more various than it
has been thought.
Presenting reduction potentials by sector and cost
Presenting stabilization scenarios of only CO2
concentrations 350~790 ppmv (445～1130
ppmvCO2eq.)

Global warming isserious. There is a way
for reduction, butpreferable strategies interms of impacts ofglobal warming andmitigation costs arepolitical issues

The Stern Review♦ The Stern Review on the Economics of Climate Change(known as the Stern Review) is released for the British governmentin October, 2006 by Sir Nicholas Stern.
<The main conclusions>♦ The cost of BAU climate change would be equivalent to around

5%~20% of GDP.
♦ Stabilizing the concentration level between 450 and 550
ppmvCO2eq. would substantially reduce the worst impacts by
climate change.
♦ The annual costs of stabilization at 500-550ppmvCO2eq. are
estimated to be around 1% of GDP, which is manageable at much
lower costs than BAU path.
♦ Stabilization at 450 ppmvCO2eq. is very difficult and costly.
♦ The earlier effective action is taken, the less costly it will be.
The review does not state any defined concentration targets but can be interpreted as
implicit suggestions to stabilize at 500~550 ppmvCO2eq. (The Stern review is almost consistent
with EU policies, if cooling effect of SOx is considered, though in the review, the effect is not considered. )Comparison of the PHOENIX and the Stern Review
The Stern Review

The PHOENIXApproach tonote thedesiredconcentration
stabilization
level

Estimating mitigation costs for global
warming (GDP loss) and damage costs fromthe impact of global warming under BAU
scenarios. By comparing the two, thedesirable concentration stabilization level is
noted, which is not actually cost-benefit
analysis, though cost benefit is partiallyconsidered.

Estimating benefits from reduced global warming andthe cost for the reduction. Cost-benefit analyses
based on weighted mitigation costs among various
impacts by specialists. Taking into account of nonquantifiable impacts of global warming andintergenerational / regional equity, specialists madethe final decision of the desirable concentration
stabilization level based on the analyses.

Baseline
scenario forassessments~2100: IPCC SRES A2
2100-2200: the world population increase
0.6% p.a. (2100: 15 billions, 2200: 27
billions) <A2 is used only for the global
warming assessment. Mitigation costs are
based on B2>~2100：IPCC SRES B2 (medium population andeconomic growth rate per capita)
2100-2200： the world population increase 0.6% p.a.
(2100: 10 billions, 2200: 11 billions) <B2 is used forthe impacts of global warming and mitigationassessments consistently.>

Monetizing
the impactsof global
warming

5% relative to GDP in 2200 for the market
impacts, 20% for various aspects such as
no-market impacts. Not evidence-based.

Based on the sectoral impacts of global warming
calculated using each index, specialists evaluated theimpacts. The derivation process is clear.

Estimated
mitigation
costs

Less than 1% relative to GDP for 500–550
ppmv-CO2eq.% stabilization until 2050.
450 ppmv-CO2eq. stabilization is too costly
and unrealistic.

Less than 1% relative to GDP for 550
ppmv(CO2only). There could be more than 10%
for 450 ppmv (CO2 only) relative to GDP. To get itaround, the introduction of innovative technologies toreduce CO2 emissions is crucial by 2030

IPCC The Fourth Assessment Report WG2♦ Observational

EU２℃ target

550 ppmv CO2 only
（1.5℃ relative to 1990）

evidences show thesignificant impacts ofglobal warming♦ If the global mean

temperature rises
2~3 ℃ relative 1990,
net benefits could
reduce 【2.5~3.5 ℃
rises relative to preindustrial. Please letme note that thecosts of measures
are not included.】♦ Corals are projected
0

1

2

3

4

Global mean annual temperature change relative to 1980-1999 (℃)

5

to be bleached orwidespread mortality
by 1~3℃ warming of
surfaces waters

The PHOENIX and IPCC Fourth Assessment Report

EU proposal
The Stern
Review?
The
government
proposalI

CO2concentration(ppm)

CO2-eqconcentration(ppm CO2eq)

Temperaturerise after theindustrial
revolution

CO2
emission in
2050(relative to2000 %)

350~400

445~4902.0~2.4-85~-50

Reduction
costs in2050
(relative to
GDP %)

Globalwarming
damages(relative to
GDP %)

less than+5.5

mixture ofloss(-)/benefits(+)

II

400~440490~535

2.4~2.8-60~-30

III

440~485535~590

2.8~3.2-30~+51.3(-0~4)

IV

485~570590~710

3.2~4.0+10~+60

0.5(-1~2)

V

570~660

710~855

4.0~4.9+25~+85VI

660~790855~1130

4.9~6.1+90~+140

The PHOENIXIn all theregions +1~5

Source: IPCC fourth assessment Report, WG2 & WG3Note) When the sum of marginal abatement costs and damage costs is the minimum, the concentration would be ideal, consideredin the cost-benefit analysis.

<reference: Stern estimate of damage impacts>
5~20% (8.6 temperature rise)What is the stabilization level of
CO2 concentration ?
What is the realistic level theworld could agree?

Emission sharing among developed anddeveloping countries♦ The article 3 of the United Nation Framework Convention on Climate

Change states that the Parties should protect the climate system on thebasis of equity and in accordance with their common but differentiatedresponsibilities and respective capabilities and that the specific needs
and special circumstances of developing country Parties, especiallythose that are particularly vulnerable to the adverse effects of climatechange, and of those Parties, especially developing country Parties, thatwould have to bear a disproportionate or abnormal burden under theConvention, should be given full consideration.
♦ The concrete meaning of ‘differentiated responsibilities’ is not clear, butdeveloped countries should be required not only to provide financial
assistance to developing countries but to set their own higher reduction
targets.
♦ From the perspective of emission sharing among developed anddeveloping countries, we should consider what meaning each level ofconcentration stabilization or the proposed long-term targets have.

CO2 emissions from fossil fuel combustion(MtC/yr)

Prospects for the future CO2 emissions





16000
14000
12000

Non A-I Countries
other than China and India

10000
2050: 70%

8000

Non A-I

China, India

6000
U. S.

4000

A-I
2000

A-I Countries other than U.S.
2000: 34%

0
2000

2010

2050: 21%

2020

2030

2040
2050
RITE, DNE21+ model

Developing countries especially have potential of significant emission increases in
the future
At least the framework is needed to substantively including the United States, China
and India and also the target level is needed to facilitate participation of thedeveloping countries in the framework.

Meaning of Halving Global Emissions by 2050

At least 60%
reductions fordeveloping
countries

Reduction rate from BaU by non A-I countries (%)

Analyses of CO2 emissions related to energyNote) Emissions in BaU
case is calculated, using the
DNE21+ model

100

95
90
85
80
75
70
65
60
55
50
50

55 60 65 70 75 80 85 90 95
Reduction rate from BaU by A-I countries (%)

100♦ The agreement of this target including developing countries

seems to be very difficult.

550 ppmv CO2 only

60
55
50
45
40
35
30

450 ppmv CO2 only

25
20
15
10
40

45 50 55 60 65 70 75 80 85
Reduction rate from BaU by A-I countries (%)♦ This level may potentiallylead to agreement
including developing
countries

90

Reduction rate from BaU by non A-I countries (%)

Reduction rate from BaU by non A-I countries (%)

Reduction Rates for Developed and Developing Countries
at each level of concentration stabilization

60
55
50
45
40
35
30
25
20
15
10
40

45 50 55 60 65 70 75 80 85
Reduction rate from BaU by A-I countries (%)

90

Regional GHG Emissions per capita (2004)

Annex I

Non-Annex I

population

19.7%

80.3%

GHG emissions

48%

52%

16.1 tCO2eq./cap

4.2 tCO2eq./cap

Emissions per capita

source）IPCC WG3 AR4, SPM

What the 2050 Halving Target of AR4 Means♦ Considering the 2050 halving target with the 2004 percapita GHG emissions by region in AR4 …
♦ If GHG emission is zero at all in Annex l countries, non-Annex l countries are also required to reduce
emissions more than 2004 (CO2 emissions from fossil
fuel combustion; Annex l: Non-Annex l=0.55:0.45)♦ If the world’s population reaches 9.4 billions in 2050

(IPCC SRES B2), the global per capita GHG emissions
would be required 2.2tCO2eq. in 2050 to achieve thehalving target, which is about half of the present
emissions from Non-Annex l countries, about 1/8 fromAnnex l countries and less than the present emissions
from Africa.

An Appropriate Stability Target of CO2
Concentration
Annual CO2 emissions (billion ton CO2eq)

16

No specific emission control of CO2: IPCC IS92a scenario

14

PHOENIX（550ppm CO2 only）

12（Quite challenging ）10

Given the possibility of a
global consensus, the bestlevel we can do

8
6
4
2

Halving emissions in 2050
(from 1990~ current emissions)0
EU 2℃ proposal-2
1990 2015 2040 2065 2090 2115 2140 2165 2190 2215 2240 2265 2290
Note）IPCC WG1 scenarios are shown in thick lines and WRE (Wigley, Richels, Edmonds) scenarios with thin lines

750 ppm
650 ppm
550 ppm
450 ppm
350 ppm

Summary♦ Major countries are required to agree on a long-term target forstabilization, so that long-term technological development, social systems
change and implementation of short- and mid-term emission targets canbe facilitated.
♦ EU and Japanese governments have no scientifically based long-termtargets.
♦ The Stern Review should be considered not as a scientifically based but
as a political report, by which EU (or UK government) attempted to justify
the target.
♦ For RITE PHOENIX project, we worked on cost-benefit estimates of global
warming effects and mitigation costs by concentration stability level andalso derived the desired stabilization level, including value judgments.
♦ Our work shows that the desired stabilization level is around 550 ppmv
CO2 only and there are no discrepancies between
IPCC AR4 and the results.
♦ The target to halve the global emissions by 2050 will make the developing
countries challenging to participate. The level should be limited at most
450 ppmv CO2 only.
♦ We should aim for a global agreement at around 550 ppmv CO2 only or
CO2eq.