Introduction of Top-down Researchin Impact Analysis
National Institute for Environmental Studies, Japan
Hideo Harasawa

Temperature Anomaly in
July 2004 (℃)

Ogasawara Islands

Precipitation Anomaly in
July 2004(%)

Ogasawara Islands

Japan Meteorological Agency

Numberof Heat Stroke Patients
気温別熱中症患者発生数
transported to hospitals（ｂ）補正済み
Standalized

201510Tokyo (center)
東京２３区
Tokyo (suburban)
東京都下Kawasaki
川崎市
Nagoya名古屋市

5020 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35

Number of heat stroke patients
熱中症患者平均搬送数
transportedto hospitals

Numberof heat stroke patients
熱中症患者平均搬送数
transported to hospitals（ａ）

Numberof Heat Stroke Patients
気温別熱中症患者発生数
transported to hospitals

3.0
2.5
2.0
1.5

Tokyo (center)
東京２３区
Tokyo (suburban)
東京都下
Kawasaki
川崎市
Nagoya名古屋市

1.00.50.0
20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35

日最高気温（℃）
Dailymax. temp(oC)

181614121086
4
20Tokyo (center)
東京２３区
Tokyo (suburban)
東京都下
Kawasaki
川崎市
Nagoya名古屋市

15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
日平均気温（℃）
Dailyave. temp(oC)

Number of heat stroke patients
熱中症患者平均搬送数
transported to hospitals

Numberof heat stroke patients
熱中症患者平均搬送数
transported to hospitals

日最高気温（℃）
Dailymax. temp(oC)
4.0
3.5
3.0
2.5
2.0
1.5

東京２３区
Tokyo (center)
東京都下Tokyo (suburban)
川崎市
Kawasaki
名古屋市
Nagoya1.0
0.5
0.0
15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

Daily日平均気温（℃）
ave. temp(oC)Annual Mean Surface Temperature by high resolution
Climate Model (K1)A1B Scenario ave. temp in 2071～2100年 minus ave temp.
in 1971～2000

NIES/CCSR/JAMSTEC

160140120
100806040

Change in higher temperaturedays（1900～2100）
Daily maximum temperature 30 oC
without heat island effects

2001900 1920 1940 1960 1980 2000 2020 2040 2060 2080 2100
1210864

Change in summer heavy rain
(June-August, 1990～2100）
Daily precipitation is more than100mm

201900 1920 1940 1960 1980 2000 2020 2040 2060 2080 2100

NIES/CCSR/JAMSTEC

・1 February 2005 – 3 February 2005
・Hadley Centre (Exeter, UK)
・HOST: DEFRA Dep. For Environment, Food and Rural Affairs
・about 200 participants from about 30 countries
The aim of the symposium was to advance scientific understanding of and encourage
an international scientific debate on the long term implications of climate change, therelevance of stabilization goals, and options to reach such goals; and to encourage
research on these issues.
Themes
1. For different levels of climate change what are the key impacts, for different regions
and sectors and for the world as a whole?
2. What would such levels of climate change imply in terms of greenhouse gas
stabilization concentrations and emission pathways required to achieve such levels?
3. What options are there for achieving stabilization of greenhouse gases at differentstabilization concentrations in the atmosphere, taking into account costs anduncertainties?

Assessment of Impacts
Compared with the TAR there is greater clarity and reduced uncertainty about the impacts of climate change across a wide rangeof systems, sectors and societies. In many cases the risks are more serious than previously thought. As noted in the TAR changes
up to 1 oC may be beneficial for a few regions and sectors such as agriculture in mid to high latitudes. A number of new impacts
were identified that are potentially disturbing.
One example is the recent change that is occurring in the acidity of the ocean. This is likely to reduce the capacity to remove CO2from the atmosphere and affect the entire marine food chain. A number of critical temperature levels and rates of change relative topre-industrial times were noted. These vary for the globe, specific regions and sensitive ecosystems. For example a regional
increase above present of 2.7 oC (this would be associated with a global temperature rise of about 1.5 oC) may be athreshold that triggers melting of the Greenland ice-cap, while an increase in global temperatures of about 1 oC is likely to leadto extensive coral bleaching. In general, surveys of the literature suggest increasing damage if the globe warms from about 1 to 3oC. Serious risk of large scale, irreversible system disruption, such as changes to the thermohaline circulation, reversalof the land carbon sink and possible destabilisation of the Antarctic ice sheets is more likely above 3 oC. Such levels arewell within the range of climate change projections for the century. In this context, some felt that it would be useful to agree upon aset of critical thresholds that we should aim not to cross. Others noted it would be difficult to objectively choose such a level.
The impacts of climate change are already being observed in a variety of sectors Ecosystems are already showing the effects ofclimate change. Changes to polar ice and glaciers and rainfall regimes have already occurred. While consistent with model
projections the links to anthropogenic climate change need to be investigated further.
Many climate impacts, particularly the most damaging ones, will be associated with an increased frequency or intensity of extreme
events. This is an important area for further work since many studies do not explicitly take into account the effects of extremes,
although it is known that such extremes pose significant risks to human well being. The heat-wave that affected Europe in 2003 isa prime example.
Adaptive capacity is highly important to determining the potential future critical or dangerous effects of climate change. In some
sectors and systems this capacity may be sufficient to delay or avoid much potential damage, though in others it is quite limited.
The capacity to adapt is closely related to how society develops with respect to technological ability, level of income and type ofgovernance. Thus adaptation and choice of development pathways need to be taken into account in developing strategies to avoid
dangerous anthropogenic climate change. This was seen particularly in the review of impacts in Africa.

Climate sensitivity and emission pathways
It is possible to decouple the issue of choice of levels from consideration of the questionof what is dangerous. The conference thus explored the emission pathways associatedwith different greenhouse gas stabilization levels and different global temperature limits.
It is helpful to take into account uncertainty in the sensitivity of the climate system togreenhouse forcing by presenting pathways in probabilistic terms. There is evidence thatthe sensitivity is now likely to be higher than quoted in the TAR, however further
observations may constrain the range.
There are a range of emission pathways that could be followed theoretically to avoid
different temperature levels. Probability analysis provides a quantitative estimate of therisk that a particular temperature level would not be exceeded. For example, limiting
warming to a 2 oC increase with a relatively high certainty requires the equivalentconcentration of CO2 to stay below 400 ppm. Conversely if less certainty was
required concentrations could rise to 550 ppm equivalent. In many cases this would
mean that concentrations would peak before stabilising, though whether this could beachieved practically was not considered.
Different models suggest that delaying action would require greater action later for thesame temperature target and that even a delay of 5 years could be significant. If action
to reduce emissions is delayed by 20 years, rates of emission reduction may need to be
3 to 7 times greater to meet the same temperature target.

Technological options
The IEA World Energy Outlook 2004 predicts that CO2 emissions will increase by 63% over 2002
levels by 2030. This is generally consistent with the IPCC emission scenarios, published in 2000.
This means that the world will, in the absence of urgent and strenuous mitigation actions in the next
20 years, almost certainly be committed to a temperature rise of between about 0.5 oC and 2 oC by
2050. Such changes will require significant investment in energy infrastructure, which will have alifetime of several decades.
Technological options for reducing emissions over the long term already exist and significant
reductions can be attained, using a portfolio of options and the costs are likely to be smaller thanpreviously considered. Sustainable development strategies and make low-level stabilization easier.
There are no magic bullets; a portfolio of options is needed and excluding any options will increase
costs; multi-gas strategies, emission trading, optimal timing and strong technology development,
diffusion and trading are all required to keep costs of low-level stabilization relatively low.
Conceptually, the challenges could be broken down into discrete wedges, covering for example
energy efficiency, nuclear energy and carbon capture and storage. Limiting climate change to 2 deg
C implies stabilizing the atmospheric concentration of all greenhouse gases.
The CO2 concentration must not exceed 500ppmv, if the climate sensitivity is 2.5 oC. Globalemissions would need to peak in 2020 and decline to 3.1 GtC/year by 2095. Inclusion oftechnological learning in models reduces emission the projected costs of reductions by over half.
Globalization and market forces will drive the developing countries to follow the same pattern
practiced by the developed countries. However energy efficiency improvements under the present
market system are not enough to offset increases in demand caused by economic growth.
Efficiency improvements and alternatives of supplies such as nuclear and renewables are of priority
for developing country to join the effort of stabilization.

New Strategic Impacts Research Project・2004FY – 5 years
・Funded by Ministry of Environment
・Project Leader: Prof. Mimura (Ibaraki Univ.) and TSU (NIES)
・Research Areas: Japan, Asia and Globe
・Top-down and Bottom-up Research(1)Emission - Stabilization – Temp. – Impacts (AIM/Impact Group)- AIM/Impact[Policy]- Climate Scenarios, Socio-economic Scenarios- Impact Function(2)Sector impacts in Japan- Water Resources (Tohoku Univ.)- Human Health (NIES and National Infectious Disease Institute)- Agriculture and Food security (National Institute for Agro-Environ. Sciences)- Forest and Ecosystem (Forest and Forest Product Research Institute)- Coastal Region (Ibaraki Univ.)- Economic assessment (Tohoku Univ. and Meijo Univ.)

Research Purpose• Development of AIM/Impact[Policy]-Stabilization, Impacts, Emission Path・ Criteria for Evaluation of Stabilization Target- Definition of “Dangerous level” from the view
points of Equity, Precautionary Principle, andUncertainties• Assessment of Stabilization Target, Emission
Target- Application of AIM/Impact[Policy]

Dangerous Level, GHG/Temp. Target, GHG Emission Path
GHG Emission Path
1412750ppm

106508・Impact Function
・Adaptation

2350

02000

2050

2100

2150

2200

2250

2300

-2

UNFCCC: Target
Atmospheric GHG
Conc.

3000
2500

250

マラリア
200

2000

150

1500
1000

飢餓100500

50

沿岸洪水
000.5

11.5

22.503

全球平均気温上昇（℃）

CarbonCycle
ModelImpact
Model

Atmospheric GHG
800

Global Temp.
TargetGlobal GHG
Conc. Target
750ppm700

Temp, Rainfall,
Sea Level Rise

4.5
4650

750ppm3.5600550500

気温上昇(℃）

ＣＯ２濃度(ppm)

650ppm

沿岸洪水
3500

水不足

300

450

41000ppm

水不足／マラリア／飢餓
350

550

6550ppm

450ppmDangerous
Level

リスク人口（百万人）

GHG Emission
Target16

ＣＯ２排出量（ＧｔＣ）

Impacts(Global, Japan)

450400

350

650

3550

2.5
450
2350

1.513000.5

Climate Model

200
2000

2050

2100

2150

2200

2250

2300

02000

2050

2100

2150

2200

2250

2300

Dangerous Level of Global Warming

GHG emission
Atmosphere

Temp. Increase
Climate Change/Sealevel riseImpacts

Human Activity↓
Emission Threshold（CL-Emission）↓
Atmospheric GHG Threshold(CL-GHG)↓
Temp. Increase Threshold(CL-Temp)↓
Climate Change Threshold(CL-CC、CL-SLR)↓
Impact Threshold(CL-Impact)↓
Mitigation and Adaptation

Critical limit, CL or threshold can be defined in the respective stepProf. Mimura (Ibaraki University)

Table Identified threshold from Impact and Vulnerability studies inJapan (CSTP, 2004)

Framework of New Top-down Impact Research
Sun-theme(1)AIM/Impact[Policy]

Sub-theme (3)Target・ Global Temp.
・ Global ＧＨＧ
・ Global GＨＧ Emission

Criteria
評価基準の検討・ ・Equity
衡平性，予防原則，不確実性といった観点から・PrecautionaryPr.
・ 既存の目標検討研究の・Uncertainty
網羅的レビュー

Optimum Emission
Temp. Change
Sea Level Rise

Sub-theme(2)Dangerous Level
・Criteria
・Emission PathCountry ＤＢ
Country Temp.
Prec. Change
Sector Impact F. (Global)

CountryImpacts

Sector Impact F.(Japan)

Sector Impacts
In Japan

Other Groups (Water Res., Forest, …..IAIM/Impact[Policy] Framework

Global Climate
Model（280km)

Regional Climate Model
To predict future regional
climate change in spatiallyhigh resolution

Nesting
Asian ClimateModel(60km)

Japan Regional
Climate Model(20km)

To use GCM output asboundary conditions forregional Climate Model

Present

50 years

100 years（1981～2000 Ave.）（2031～2050 Ave.）（2081～2100 Ave.）

Predicted Average
Temperature inJanuary

Present

50 years

100 years（1981～2000 Ave.）（2031～2050 Ave.）（2081～2100 Ave.）

Predicted Average
Temperature inJulyPresent

50 years

100 years（1981～2000 Ave.）（2031～2050 Ave.）（2081～2100 Ave.）

Predicted Average
Precipitation inJanuary

Present50 years

100 years（1981～2000 Ave.）（2031～2050 Ave.）（2081～2100 Ave.）

Predicted Average
Precipitation in July危険なレベルを超えないための道筋の範囲：
GHG 500ｐｐｍあたりを目標に早期の削減が必要（ＡＩＭによる計算結果。気候感度2.5度、社会厚生関数最大化、時間選好率３％）

Year

ＧＨＧ5001.0Yearz To achieve around 2℃ temperature increase in 2100, 500ppmv
cap on total GHG constraint is neededz Reduction required to achieve 500ppmv cap on total GHG
constraint ►►► 4.4 GtCeq/yr (16.1 GtCO2eq/yr) in 2020 and 7.9
GtCeq/yr (29.0 GtCO2eq/yr) in 2030

2100

2090

2080

2070

2060

0.0
2050

2100

2090

2080

2070

2060

2050

2040

2030

2020

2010

2000

1990

02.0

2040

5GHG-600ppmv

2030

GHG500ＢａＵ

GHG-500ppmv

2020

GHG600

103.0

2010

15BaU

2000

BaU

4.0

1990

Temperature increase (1990=0)CO2eq emission (GtCeq/yr)

20

研究
例えば、全ガスの温室効果ガス濃度が500ppmCO2eq、出力例 600ppmCO2eqを超過しないという抑制目標を仮定すると、さらに，その結果，各国の温暖化影響は・・・
 SRESSRES-B2: BaU▲ GHGGHG-500ppmv▲ GHGGHG-600ppmv

Wheat (India)-5-10-150-20-25-30
2000

2020

2040

2060

Year2080

Change of rice productivity(%)

Change of wheat productivity(%)

0-5-10Rice(India)-15
2100-20-25-30
2000

2020

2040 2060
Year2080

2100