Ministry of the Environment
Japan

Climate Regime Beyond 2012:
Key Perspectives(Long-Term Targets)
2nd Interim Report

May 2005

Sub-Committee forInternational Climate Change Strategy,
Global Environment Committee,
Central Environment Council,
Ministry of the Environment, Japan

Table of Contents
1. Preface……………………………………………………………. 1

2. International Developments Related to Long-Term…….... 1
Targets for Controlling Climate Change
2.1 Ultimate Objective of UNFCCC and Long-Term Targets …………. 1
2.2 International Developments Related to the Setting ofLong-Term Targets …………………………………………………. 2
2.3 Why Japan Needs to Consider the Setting of Long-Term Targets …. 7

3. The Significance of Establishing Long-Term Targets ……9
4. Conditions Precedent to Debating Long-Term Targets …. 10
5. Temperature Increase and Related Impacts Due to…… 12
Climate Change
5.1 Global Impacts …………………………………………………….. 12
5.2 Impacts on Asia ……………………………………………………. 14
5.3 Impacts on Japan …………………………………………………... 16

6. Establishing Long-Term Targets…………………………... 19

6.1 Approaches to Establish Long-Term Targets ……………………… 19
6.2 The Relationship Between GHG Concentrations and Global
Emission Paths …………………………………………………….. 21

7. Agenda for the Future………………………………………... 26

7.1 Further Study concerning Long-Term Targets …………………….. 26
7.2 Risk Management of Climate Change …………………………….. 26
7.3 Clarification of "the Effects of Climate Change" in the Context
of a Closely Integrated Global Economy ………………………….. 28

References………………………………………………………….. 30

Attachment ..………………………………………………………... 32
Members of the Sub-Committee for International Climate Change
Strategy1. Preface○ The Sub-Committee for International Climate Change Strategy was establishedunder the Global Environment Committee, Central Environment Council,
Ministry of the Environment, Japan, in January 2004 with the aim of collecting
and organizing reference materials for the consideration of a climate regime
beyond 2012. The Sub-Committee held its first meeting in April 2004, andissued its first interim report in December of the same year after a total of sevenmeetings. The interim report gave shape to what is meant by the ultimate
objective of the United Nations Framework Convention on Climate Change(UNFCCC), and considered the regime required to realize the objective from asystemic perspective.
○ In the three meetings it held since April 2005, the Sub-Committee collected andorganized reference materials presenting current scientific knowledge
concerning long-term targets such as the range of control of temperature rise,
and atmospheric GHG concentrations and global emission paths, focusing inparticular on materials, including examples of Japanese research, dealing withtemperature rise and its impacts due to climate change. This report, the SubCommittee's 2nd Interim Report, presents the findings of these activities.

2. International Developments Related to Long-Term Targets
for Controlling Climate Change
2.1 Ultimate Objective of UNFCCC and Long-Term Targets○ The ultimate objective of the United Nations Framework Convention on Climate
Change (UNFCCC) is the "stabilization of greenhouse gas concentrations in theatmosphere at a level that would prevent dangerous anthropogenic interferencewith the climate system," - in other words, the "stabilization of greenhouse gas
concentrations in the atmosphere at a level that does not adversely affect natural
ecosystems and humankind." This level "should be achieved within a time-frame
sufficient to allow ecosystems to adapt naturally to climate change, to ensurethat food production is not threatened and to enable economic development to1

proceed in a sustainable manner."○ Various countries have implemented UNFCCC-based measures aimed atcontributing to the achievement of the Convention's ultimate objective, and the
Kyoto Protocol, which is a concrete framework for GHG emission reduction,
went into effect on February 16, 2005.
○ Now that the Kyoto Protocol has gone into effect, there is growing debate about
the next global climate regime beyond 2012 when the first commitment periodof the Protocol ends (hereinafter referred to as "the next regime"). The next
regime needs to bring us closer to achieving the ultimate objective of theConvention. Consequently, efforts must be made to specify as far as is possible
the direction that the international community should pursue, and to quantify andgive concrete shape to the ultimate objective of the UNFCCC.
○ The setting of long-term targets is in effect the process of quantifying and giving
concrete shape to the ultimate objective of the UNFCCC, and is an attempt tofurther clarify the targets that the international community has already agreed
upon.

2.2 International Developments Related to the Setting of Long-TermTargets○ In its Third Assessment Report issued in 2001, the Intergovernmental Panel on
Climate Change (IPCC) provided its assessment of scientific data and evidence
concerning "dangerous anthropogenic interference with the climate system," orin other words, the impacts of human-induced climate change (see Tables 2.1
and 2.2). Since then, further new information in this field both from Japan andfrom the rest of the world has added to our body of knowledge (see Table 2.3).

2

Table 2.1 Positive and negative impacts of climate change(source: based on the IPCC Third Assessment Report)
1. Projected positive impacts(Impact on crop yields)
Increased potential crop yields in some regions at mid-latitudes for increases in temperatureof less than a few degrees Celsius(Impact on timber resources)
Potential increase in global timber supply from appropriately managed forests(Impact on water resources)
Increased water availability for populations in some water-scarce regions(Impact on human health)
Reduced winter mortality in mid- and high latitudes(Impact on energy demand)
Reduced energy demand for space heating due to higher winter temperatures
2. Projected negative impacts(Impact on crop yields)
x General reduction in potential crop yields in most tropical and sub-tropical regions for mostprojected increases in temperature
x General reduction, with some variation, in potential crop yields in most regions in
mid-latitudes for increases in annual-average temperature of more than a few degrees
Celsius(Impact on water resources)
Decreased water availability for populations in many water-scarce regions, particularly in the
sub-tropics(Impact on human health)
Increase in the number of people exposed to vector-borne diseases (for example, malaria) andwater-borne diseases (for example, cholera) and an increase in heat-stress mortality(Impact on human settlement)
Widespread increase in the risk of flooding for many human settlements (tens of millions of
inhabitants in settlements studied) from both increased heavy precipitation events andsea-level rise
(Impact on energy demand)
Increased energy demand for space cooling due to higher summer temperatures3

Table 2.2 Relationship between climate change and extreme climate events(source: IPCC Third Assessment Report)
Likelihood that events
have already occurred(latter half of 20th
century)

Projected changes in extreme climate
phenomena

Likelihood of occurrence(21st century)

LikelyHigher maximum temperatures, more
hot days and heat waves over nearly
all land areas

Very likely

Very likely

Higher minimum temperatures, fewer
cold days, frost days and cold waves
over nearly all land areas

Very likely

Very likely

Reduced diurnal temperature range
over most land areas

Very likely

Likely over many areas

Increase of heat index over land areas(a)Very likely over most areas

Likely over many
Northern Hemispheremid- to high latitude
areas

More intense precipitation events (b)Very likely over many areas

Likely in a few areas

Increased summer continental drying
and associated risk of drought

Likely over most mid-latitudecontinental interiors (lack ofconsistent projections in otherareas)

Not observed in the few Increase in tropical cyclone peak wind Likely over some areas
analyses available
intensities (c)Insufficient data forassessment

Increase in tropical cyclone mean andpeak precipitation intensities (c)Likely over some areas(a) Heat index is a combination of daily mean temperature and relative humidity.
(b) For other areas there are either insufficient data or conflicting analyses.
(c) Past and future changes in tropical cyclone location and frequency are uncertain.

4

Table 2.3 New findings related to climate change{ Large-scale disappearance of Arctic ice due to large temperature rise (November 9, 2004)1(Arctic Council: Arctic Climate Impact Assessment (ACIA))¾ Global warming is causing the Arctic ice cap to rapidly melt, with the average extent of
sea-ice cover in summer decreasing by 20% over the past 30 years. By the end of the 21st
century, it is predicted that Arctic temperatures will rise by 4-7ºC, causing summer sea-ice
extent to be reduced by more than 50%, and record melting of the Greenland Ice Sheet.
{ Many impacts already appearing in USA (November 9, 2004)2(Report on Observed Impacts of Global Climate Change in the U.S.)¾ Half of the approximately 150 wild animal and plant species surveyed have been affected by
global warming.
{ Human activity implicated in Europe's 2003 heat wave (Nature, December 2004)3¾ It is very likely (confidence level > 90%) that human influence has at least doubled the riskof extreme heat waves like that which hit Europe in 2003.
{ Avoiding Dangerous Climate Change conference (UK, February 1-3, 2005)4¾ Compared with the IPCC Third Assessment Report (2001), there is greater clarity andreduced uncertainty about the impacts of climate change. In many cases the risks are more
serious than previously thought. If concentrations were to rise to 550 ppm CO2 equivalent,
then it is unlikely that warming would be limited to 2ºC above pre-industrial levels.
¾ Different models suggest that delaying action would require greater action later for the same
temperature target and that even a delay of 5 years could be significant.
¾ To stabilize GHG concentrations, technological options for significantly reducing emissions
over the long term already exist. Large reductions can be attained, using a portfolio of
options whose costs are likely to be smaller than previously considered.
{) Receding Himalayan glaciers, disappearance of Kilimanjaro's ice (March 2005)(WWF report)5¾ Receding Himalayan glaciers, and disappearance of Kilimanjaro's ice cap could cause
serious water shortages.

○ On the occasion of negotiating the Kyoto Protocol in 1996, the European Union
set a long-term target of limiting temperature rise to 2ºC compared with
pre-industrial levels, and it still remains committed to this target. At European
Council, the EU has stated its views on the amount of GHG emission reduction
required of developed countries by 2020, and at EU Environment Minister-level
discussions, it has also stated its views on the reduction required of developed
countries by 2050, respectively, to achieve this target (see Tables 2.4 and 2.5). In
the USA, a resolution submitted to the Senate calls for the setting of long-termtargets, etc. (see Table 2.6)

5

Table 2.4 Key points of EU Environment Council Conclusions on
climate change (March 10, 2005)
 The global nature of climate change calls for the widest possible cooperation by all
countries in accordance with their common, but differentiated responsibilities.
 In order to have a reasonable chance to limit global warming to no more than 2ºC comparedwith pre-industrial temperatures, stabilization of atmospheric GHG concentrations well
below 550 ppmv CO2 equivalent may be needed.
 Recent scientific research and work indicate that limiting global warming to the 2ºC target
will require global GHG emissions to peak within 2ºC, followed by substantial reductions in
the order of at least 15% and perhaps by as much as 50% by 2050 compared to 1990 levels.
 The EU looks forward to exploring with other Parties possible strategies for achieving
necessary emission reductions, and believes that, in this context, reduction pathways by thegroup of developed countries in the order of 15-30% by 2020 and 60-80% by 2050
compared to 1990 levels should be considered.

Table 2.5 European Council Presidency Conclusions (March 23, 2005)
 To achieve the ultimate objective of the UNFCCC, average global surface temperature
increase should not exceed 2ºC above pre-industrial levels.
 The widest possible cooperation by all countries and their participation should be ensured in
exploring options for a post-2012 regime in the context of the UN climate change process.
 Developed countries should consider GHG emission reductions in the order of 15-30% by
2020, compared with 1990 levels, and beyond, in the spirit of the conclusions of theEnvironment Council. These reduction ranges are to be viewed in the light of future workon how the objective can be achieved, including the cost-benefit aspect.
 Consideration should also be given to ways of effectively involving majorenergy-consuming countries, including those among the emerging and developing countries.

Table 2.6 U.S. Senate Feinstein and Snowe Joint Resolution(Introduced February 16, 2005)
Resolution introduced by Senators Dianne Feinstein (Dem), Olympia Snowe (Rep) and 12 othersenators, calling for the United States to act to reduce GHG emissions by:(1) carrying out reasonable and responsible actions to ensure significant and meaningful
reductions in emissions of all GHGs;(2) generating climate-friendly technologies by enacting and implementing policies andprograms to address all GHG emissions to promote sustained economic growth;(3) participating in international negotiations under the UNFCCC to achieve significant,long-term, cost-effective reductions in global GHG emissions; and(4) supporting the establishment of a long-term objective to prevent the global averagetemperature from increasing by greater than 3.6 degrees Fahrenheit above pre-industrial
levels.
Note: A joint resolution requires the approval of both houses of Congress and the signature of the President, just as a bill does,
and has the force of law if approved.

62.3 Why Japan Needs to Consider the Setting of Long-Term Targets○ In view of the global scale of the likely impacts of climate change, the issue ofclimate change requires a global response. Now that scientific knowledge has
accumulated, and other nations and regions are proposing long-term targets, it isimportant that Japan too give serious consideration to the significance andchallenges of setting its own long-term targets such as the range of control oftemperature rise for GHG emission reduction.
Note: The setting of short and medium-term targets and divizing concrete
policies should be considered in light of long-term targets. In the event that
long-term targets are framed in terms of range of temperature rise or
atmospheric GHG concentrations, such numerical targets represent upper limits
that should not be exceeded, with the period by which such targets are achieved
being dictated by GHG emission paths, climate system behavior and so forth. In
the event that long-term targets are framed in terms of such policy targets as
GHG reduction, we envisage short-term targets applying to the period from thepresent up to around 2020, medium-term targets to the period up to 2030-2050,
and long-term targets to the period up to around 2100.

○ Long-term targets can be set for any of the five stages of climate change - humanactivities (energy production and consumption), GHG emissions, atmospheric
GHG concentrations, global mean temperature rise, and climate change impacts(see Figure 2.1). We have focused our consideration of long-term targets inparticular on climate change impacts, global mean temperature rise, andatmospheric GHG concentrations.

7Average temperature;

GHG concentrations

thermodynamic response

Stage III

Stage IV

Climatic effects; impacts on

Emissions of GHGs

human, natural systems

Stage II

Mitigation

Stage V
Human activities: Energy production
and consumption, Industrial processes,
Land use
Stage I
Source: Pershing, J. and F. Tudela (2003)6

Figure 2.1 The Climate Change Cycle

8

Adaptation

3. The Significance of Establishing Long-Term Targets○ Although the Kyoto Protocol is the first step toward achieving the ultimate
objective of the United Nations Framework Convention on Climate Change, itdoes not necessarily follow that the climate change problem will be resolved
when the first commitment period of the Protocol concludes in 2012. Theinternational community is being challenged with a question as to which
direction the ensuing second and third steps should take and where to set thetarget. Long-term targets hold significance as indications of the direction to betaken in establishing the next regime. Setting a clear direction to be followed
also contributes to the realization of a low carbon emitting economy on aworldwide scale and to an assurance of the attainment of UNFCCC’s ultimate
objective.
○ As clearly noted in the first interim report of this sub-committee, long-termtargets have significance from the standpoint of global risk management as well.
Clearly-defined long-term objectives would help the international community
become more cognizant of the inevitability of the impacts, to an extent, broughtby climate change and clarify the roadmap for establishing the measures for
reduction of greenhouse gas emissions and adaptation to climate change. Sharingof a common recognition throughout the world in this manner in the midst of acall for the establishment of the effective next regime would also accelerate theprogress of international negotiations in which major powers participate.
○ In addition, at a national level, the setting of long-term targets would give amessage to citizens that would bear substantial meaning from the aspect ofarousing public opinion and promoting concrete actions.
○ Furthermore, long-term objectives also have meaning from the standpoint of
implementing sustainable climate change measures. While the future direction
pertaining to climate change remains as uncertain as it is now, we cannot expect
adequate public works investments that incorporate measures to address climate
9change and large-scale private investments that contribute to such measures. In
order to promote a broad range of such measures as private investments,
technological development and creation of institutional systems, it isindispensable to send out reliable policy signals based on the well-establishedlong-term targets.

4. Conditions Precedent to Debating Long-Term Targets○ In order to examine the long-term objectives, it is necessary to clarify "when,
where and how" to capture and observe the effects of climate change. Morespecifically, it is necessary to examine them after the following preconditions
have been clarified.
 The type of gas in question The benchmark for evaluation (The question of "When?" in establishing areference base for discussion.) The geographic scope of evaluation (The question of "Where?" whenestablishing a geographic scale for discussion, i.e., is it global or regional?) The index for evaluation of dangerous levels (The question of "How?" inestablishing an index for evaluation.)○ Although much international discussion and research related to long-term targets
is already underway, there are many instances where these preconditions are notnecessarily clarified, with a result that the issues are confused.1 Thus, in thisreport we presuppose to organize scientific findings through: Covering all GHGs, referring, as necessary, to the impacts caused by six of
1

There is debate concerning the benchmark point of evaluation, for instance, in regard to whether to
set it at a point before the Industrial Revolution (around 1750); in the pre-industrial era, i.e., before
the society was industrialized (about 1850); at 1990 or elsewhere. In regard to the period prior to theIndustrial Revolution and pre-industrialization, however, actual global average temperature levels
can be considered almost equal.

10those as identified in the Kyoto Protocol (carbon dioxide [CO2], methane[CH4], nitrous oxide [N2O], sulfur hexafluoride [SF6], hydrofluorocarbons[HFCs] and perfluorocarbons [PFCs]) Using the pre-industrialization level as a benchmark (around 1850),
 Dealing with the global average temperature, and While focusing on the maximum temperature rise.
Accordingly, our point revolves around the temperature rise that presupposesthat there was a temperature increase of about 0.6ºC during the 20th century.
○ Recently, the following two values are often discussed among scientists as thethresholds of the effects of climate change.
 Type 1 Thresholds: The value beyond which damages the policy makers
consider to be intolerable. In other words, the thresholds related toaccumulated effects. (e.g., the effects on ecosystems, food production,water resources, coastal regions, meteorological disasters, human health,economic development, etc.)
 Type 2 Thresholds: The value that should not be exceeded in order tomaintain the stability of the principal process of the climate system. In
other words, the thresholds concerning the occurrence of catastrophic andirreversible damage. (e.g., the shutdown of deep ocean circulation, thecollapse of the West Antarctic Ice Sheet, etc.)
In this report, scientific knowledge will be presented with the thresholds of these
two types taken into consideration. While decisions concerning dangerous levels
in Type 1 Thresholds include an element of value judgment, in Type 2
Thresholds, the difference of value judgment is considered to be small becauseof the fact that it depends on phenomena with the potential to produce grave andirreversible effects upon humankind.

11

5. Temperature Increase and Related Impacts Due to Climate
Change○ While it is essential to consider the worldwide consequences of climate change
when formulating appropriate responses, the strategy of Japan must be based on anunderstanding of how Japan will be affected in particular. In this connection, it isimportant to note that the effects on Japan cannot be understood only within adomestic context; Japan is part of Asia, a region whose nations are closelyinterconnected in many ways, and where region-wide impacts are anticipated andregional measures to address climate change are important. It is important, therefore,
to be aware of regional effects that may occur in Asia due to climate change. For
these reasons, we consider how temperature increases due to climate change, andrelated impacts, will affect not only the world as a whole, but also the Asia region
and Japan itself.

5.1 Global Impacts○ Representative scientific knowledge concerning types of impacts resulting fromtemperature increases (global averages) are as follows.
(1) Type 1 Thresholds (Cumulative Effects)
Impacts on Ecosystems
According to the Third Assessment Report of the Intergovernmental Panelon Climate Change (2001), it is projected that a warming of 1°C would threaten
the survival of species that currently are living near the upper limit of theirhabitable temperature ranges, notably in alpine regions and in the southwest ofAustralia. In addition, according to the same report (2001), major coralbleaching events could occur if average seasonal sea-surface temperatures
increase by >1ºC.
Impacts on Water Resources, Coastal Zones and Human HealthParry et al. (2001)7 indicate that populations exposed to risks of water
shortages, malaria, starvation and coastal flooding would rise drastically if the12

global average temperature were to rise 1.5-2.0ºC above pre-industrial (1850)
levels (see Figure 5.1).
The Third Assessment Report of the IPCC (2001) reports that projections of
the mean annual number of people who would experience flooding due tocoastal storm surges would increase several fold (by 75-200 million people
depending on adaptive responses) for mid-range scenarios of a 40-cm sea-level
rise by 2080 relative to scenarios with no sea-level rise.

Source: Parry, et al. (2001)7
Figure 5.1 Populations at Risk Due to Different Global Temperature Increases
Above Pre-Industrial Levels by 2080
Impacts on Food Production

According to the Third Assessment Report of the IPCC (2001), mean annual
temperature increases of 2.5ºC or greater would prompt food prices to increase
as a result of a slowing in the expansion of global food production capacity
relative to growth in global food demand. Moreover, yields of some crops intropical locations would decrease with even minimal increases in temperature,
because such crops are produced near their maximum temperature tolerance anddryland/rainfed agriculture predominates.

13

(2) Type 2 Thresholds (Catastrophic and Irreversible Impacts)
Shutdown of Deep Ocean Circulation (Thermohaline Circulation, THC)
Deep ocean circulation plays an important role in Earth’s climate. There is apossibility that a weakening of deep ocean circulation patterns may lead tocolder climatic conditions in Northern Europe. According to the IPCC Third
Assessment Report (2001), most Atmosphere-Ocean General Circulation
Models (AOGCM) show only very low probability that there will be fullcollapse of the thermohaline circulation by 2100. However, O'Neill and
Oppenheimer (2002)8 suggest a limit at 3ºC warming over 100 years from 1990
to avert shutdown of the thermohaline circulation; also, Stocker and Schmittner(1997)9 and Schlesinger et al. (2004)10 indicate the possibility that warming inthis century could cause a shutdown of deep ocean circulation.
Collapse of the West Antarctic Ice Sheet (WAIS)
It is estimated that a complete collapse of the West Antarctic Ice Sheet(WAIS) would lead to a 4-6 meter rise in sea level. According to the IPCC Third
Assessment Report (2001), a complete collapse of WAIS is likely to take at least
several thousand years. However, there is a possibility that warming in thiscentury could trigger a collapse of WAIS. O'Neill and Oppenheimer (2002)8
indicate that disintegration of WAIS could ultimately occur with a global mean
temperature 3ºC warmer than today.

5.2 Impacts on Asia
○ The IPCC Third Assessment Report (2001) includes an analysis of impacts due
to climate change in the Asian region. The main results of this analysis are as
follows.
Agriculture and Food Security
Lack of food security is the primary concern for Asia. Crop production andaquaculture would be threatened by thermal and water stresses, sea level rise,increased flooding, and strong winds associated with intense tropical storms.

14

Ecosystems and Biodiversity
Climate change would exacerbate current threats to biodiversity resulting
from land–use/cover change and population pressure in Asia.
Permafrost melting resulting from global warming would increase thevulnerability of many climate-dependent sectors, affecting the economy inNorthern Asia.
Water Resources
Freshwater availability is expected to be highly vulnerable to anticipatedclimate change.
Extreme Weather Events
Developing countries of temperate and tropical Asia already are quite
vulnerable to extreme climate events such as typhoons/cyclones, droughts, andfloods. Climate change and variability would exacerbate these vulnerabilities.
Deltas and Coastal Zones
The large deltas and low-lying coastal areas of Asia would be inundated bysea-level rise.
Human HealthWarmer and wetter conditions would increase the potential for higher
incidence of heat-related and infectious diseases in tropical and temperate Asia.

Table 5.1 Sensitivity of Selected Asian Regions to Climatic Change
Change in Climatic Elements
and Sea-Level Rise

Vulnerable Region

Primary Change

0.5-2ºC(10- to 45-cm sea-level rise)

Bangladesh
Sundarbans-Inundation of about 15% of national
land area-Increase in salinity

4ºC(+10% rainfall)

Siberian permafrosts-Reduction in continuous permafrost-Shift in southern limit of Siberian
permafrost by 100-200 km northward>3ºC(>+20% rainfall)

Water resources in
Kazakhstan-Change in runoff

15

~2ºC
(–5 to 10% rainfall; 45-cm
sea-level rise)

Low-lying areas of
Bangladesh-About 23-29% increase in extent ofinundation

Source: IPPC Third Assessment Report (2001)

5.3 Impacts on Japan○ According to the IPCC Third Assessment Report (2001), mid- to high-latitude
regions of the Northern Hemisphere have experienced the greatest rise intemperature during the latter half of the 20th Century. Over the one hundred year
period of the 20th Century, while global average temperature rose 0.6ºC, averagetemperatures in Japan rose by one degree. In the future, with the advance of
global warming, the extent of temperature rise in Japan is anticipated to exceed
the global average.
○ Scientific knowledge is being accumulated regarding the levels of temperaturerise and sea-level rise as well as their effects in Japan.
Future Climate Change
Based on the results of the Earth Simulator developed by the Center for
Climate System Research (CCSR) of the University of Tokyo, the National
Institute for Environmental Studies (NIES) and the Japan Agency for
Marine-Earth Science and Technology (JAMSTEC) (2004), in an
economy-focused scenario (with carbon dioxide concentrations rising to 720ppm
in 2100), the daily mean temperature of summer days in Japan (June throughAugust) will be 4.2ºC higher compared to now, the annual average precipitation
will increase by 19%, and, except in some areas, the number of "tropical" days
(days with high temperatures of 30ºC or above) will increase by approximately
70 days; the frequency of heavy rain is also expected to increase.
Impacts on Coastal Zones
According to the study "The Impacts of Global Warming on Japan – 2001"11
a rise of sea level of 1 meter would result in the eroding of 90.3% of the total
area of Japan’s sandy coastlines; moreover, it has been estimated that a rise of
sea level of 1 meter would require raising the height of dikes to 2.8 meters along
sandy seashores exposed to the open ocean, and 3.5 meters along inland sea
16areas.
Impacts on Beech (Fagus crenata) Forests
According to estimates by the Forestry and Forest Products ResearchInstitute of Japan, in a scenario for 2090 in which temperatures have risen 3.6ºC
above current temperatures, areas in Japan with a 50 or more percent probabilityof distribution of beech (Fagus crenata) forests are expected to decrease bynine-tenths (Matsui et al., 2004).12
In this estimation, the temperature in 2090 is based on a down-scaled versionof the results from the CCSR/NIES global circulation model (GCM) using themethod employed by Yokozawa et al. (2003).13

of beech(A) Actual distribution and predicted probability distributions of beech (Fagus
crenata) under (B) the current climate and (C) the CCSR/NIES climate change
scenario in the 2090s (modified from Matsui et al. 2004).
By Dr. N. Tanaka (Forestry and Forest Products Research Institute)

Figure 5.2 Predicted Impacts of Climate Change on Beech (Fagus crenata)
Forests

17

Table 5.2 Climate Change Sensitivities/Thresholds (Temperature Increases)
Temperature
Increase

1.0–1.9ºC

2.0–2.9ºC

3.0-3.9ºC

4.0ºC ormore

Examples of Impacts

Sectors Affected-Increase of 10-40% in peak flow volumes for mostrivers during flooding-Loss of habitat for rock ptarmigan (Lagopus mutus) of
40-60%-Decrease in alpine grassland communities andsub-alpine coniferous forests-Increase in sales of summer commodities of approx.
5%-Coniferous forests reduced to one quarter of current
area-Two more generations of diamondback moth pests per
year-Water demand increase of 1.2-3.2%-Water resources and aquatic
environments-Terrestrial ecosystems-Increase in annual carbon loss of 30%-Seasonal shift from C3 to C4 plants 2-3 weeks earlier.
-Crabrass germination possible year-round-Terrestrial ecosystems-Industry and energy-Terrestrial ecosystems-Agriculture, forestry andfishery-Water resources and aquatic
environments-Terrestrial ecosystems-Agriculture, forestry andfishery-Agriculture, forestry andfishery

Table 5.3 Climate Change Sensitivities/Thresholds (Sea-Level Rise)
Sea Level
Rise

Examples of Impacts

30cm or less

-Erosion of 108 km2 of sandy shorelines (56.6% of thetotal nationwide)

31-60 cm

61-99 cm

1 m or more

- Loss of tidal flats of 120 m off-shore with sea-level riseof 40 cm and average tidal range of 2 m-Dramatic increases in overtopping waves on reinforced
shorelines with slopes gentler than 70% gradient.
-Erosion of 81.7% of total sandy shorelines nationwide-Tenfold increase in wave overtoppings of reinforced
shorelines with gentle slopes of more than 70% gradient-Erosion of 90.3% of sandy shorelines nationwide-Population residing below average high tide level
increased from the current 2 million to 4.1 million, withan increase in value of assets situated below the hightide level from the current 54 trillion yen to 109 trillion
yen-Cost for measures related to port facilities andassociated coastal structures totalling 11.5 trillion
yen-Height of dikes required: 2.8 m along sandy seashores
exposed to the open ocean, and 3.5 m along inland sea
areas.

Sectors Affected-Marine-Marine-Coastal Zone
-Marine-Coastal Zone
-Marine-Coastal Zone

-Coastal Zone
-Land protection, conservationand human habitation

Source: Tables 5.2 and 5.3 both derived from publication by Prof. Mimura of Ibaraki University.14

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6. Establishing Long-Term Targets
6.1 Approaches to Establish Long-Term Targets○ As shown in Chapter 5, scientific knowledge has already been accumulated
regarding temperature increase and its impacts caused by global warming.
Taking into account the scientific knowledge obtained so far, the establishmentof long-term targets for limiting the extent to which the temperature will increase
can be organized as follows. On the basis of the approach described in Chapter 4,
presented below is the scientific knowledge concerning the impacts that would
be brought about by several maximum increases in average global temperature,compared to pre-industrial levels (circa 1850).
Temperature increase of 1ºC or less:
There is a strong possibility that there would be some impacts on fragile
ecosystems with an increase in temperature of even 1ºC. For this reason, if
preventing impacts on fragile ecosystems were a priority, limiting the temperature
increase to 1ºC or less is needed. On the other hand, taking into consideration thefact that the temperature has already increased about 0.6ºC over the 20th century
and considering such things as the future population dynamics and economic
growth of the world, limiting the temperature increase to 1ºC or less would,
realistically speaking, be extremely difficult.
Temperature increase of 2ºC or less:
Indications are that negative impacts would appear on a global scale if thetemperature increase were to be 2-3ºC. Consequently, limiting the temperature
increase to 2ºC or less would prevent negative impacts on a global scale.
Furthermore, research has shown that the scale of those negative impacts would
increase steeply at around the 2ºC point, and we can see that 2ºC has a definite
meaning from the standpoint of effectively preventing large-scale expansion ofnegative impacts.

19

(Reference) IPCC Third Assessment Report (excerpt)
For temperature increases of less than 2-3ºC, some regions may have net benefits andsome may have net damages. If [the] temperature increases more than 2-3ºC, most regions
have net damages, and damages for all regions increase at higher changes in global
average temperature.

Temperature increase of 3ºC or more:
Some research indicates that a temperature increase of more than 3ºC exceeds
the level at which the stability of the climate system is maintained (Type 2
Thresholds), heightening the likelihood of such things as the shutdown of deep
ocean circulation. Because there would be an increased risk that there would besevere and irreversible negative impacts if this level were exceeded, this must be
avoided. The research concerning the level at which the stability of the climate
system is maintained is limited, however, and further scientific knowledge needs
to be accumulated.
○ Taking all this scientific knowledge into account, we think the starting point forstudying long-term targets, while noting the points below, should for now be theapproach that would limit the temperature increase to 2ºC.
 Scientific uncertainty still remains. Scientific knowledge concerning theimpacts, etc., should continue to be further accumulated in the future.
 It should be noted that the temperature has already increased around 0.6ºC
compared to the pre-industrial era; that, as a result of this, impacts are
already evident in every part of the world; and that the temperature increasein the mid- and high-latitude regions of the Northern Hemisphere, which
include Japan, has been comparatively greater than for the global averagetemperature.
 Given fears that a temperature increase of even 1ºC will produce impacts onsome fragile ecosystems, ongoing research and study of how to deal withsuch impacts should be continued.
 It should be recognized that greenhouse gases (GHGs) must be reduced on a
global scale even to limit the temperature increase to 3ºC.
○

While the above is presented on the basis of the scientific knowledge

20

concerning impacts and the like, the establishment of long-term targets should not
be determined solely by science; this must ultimately be decided in theinternational community. We would like to expect that Japan, while moving
forward with a broad-based, constructive domestic debate about these long-termtargets, will also play a leadership role in consensus-building in the international
community.
○ It is particularly hoped that from now on the assessment and forecasting ofvulnerability, impacts, adaptability and the like will be carried forward on theregional level and on the country level. It is important to think how to advanceinternational consensus building regarding long-term targets based on suchknowledge. Japan must thoroughly assess such things as the impacts on itself andcontinue working on designing an international strategy based on the results.
When doing so, it is important to be very mindful not only of the direct impacts
that climate change has on Japan, which largely depends on overseas for its foodand resources, but also of the indirect impacts it has through trade and the like.

6.2 The Relationship Between GHG Concentrations and Global Emission
Paths○ In line with the above discussion, and with limiting the temperature increase to
2ºC in mind, we present the scientific knowledge concerning the atmospheric
GHG concentrations and global emission paths.
○ When the CO2-equivalent concentration is calculated on the basis of radiative
forcing as demonstrated in the IPCC Third Assessment Report (2001), theconcentration for all GHGs has risen compared to pre-industrial levels, from theCO2 equivalence of 280ppm to 359ppm in the year 2000 (the CO2-only
concentration rose from 280ppm to 368ppm), while the temperature has
increased approximately 0.6ºC.
○ According to recent research, even if all GHGs were stabilized at 550ppm, it is21highly possible that the temperature increase will exceed 2ºC; thus, it would benecessary to limit the concentrations well below 550ppm in order to hold thetemperature increase to under 2ºC. For example, trial calculations using the
Asian Pacific Integrated Model (AIM) showed that a level of around 475ppm(see Notes 1, 2 and 3) was necessary (see Figures 6.1 and 6.2).
Climate Impact Thresholds
Dynamic optimizing model
For global multi-gas emission
constraint(General equilibrium + climate
model)The AIM model (AIM/Impact [Policy]) sets
future targets for rises in global average

Global multi-region and multi-sector
impact assessment and adaptation
model (database-type model)

temperature and sea level and for GHG
concentration in the atmosphere. Using
these targets, it estimates optimal GHG

Global multi-region multi-gas
emission constraint
energy-economic model(general equilibrium model)

Global emissions permit pathemission paths (worldwide) and therelevant burden sharing of emission
control for each region. It also estimatesthe impacts of global warming (physical

Burden sharing scheme

Flexibility scheme foremission constraint

Emission permit pathat country level

impacts and economic impacts) by country
and by sector, assuming those GHG
emission paths.

Fig. 6.1 Features of the AIM model (AIM/Impact [Policy])

Temperature rise (0.6ºC in 1990)

5.0

4.0

3.0

2.0

1.0

0.0

Year
(Climate sensitivity 2.6 degrees, discount 4%)
BaU

GHG-475ppm

GHG-500ppm

GHG-550ppm

GHG-650ppm

Fig. 6.2 Trial calculations with AIM model on the relationship between
stabilized concentration levels and temperature increase22

(Note 1) At present, the atmospheric concentration of CO2 is increasing at a rate of 1.6ppm
annually (average value for 1983-2002 – Japan Meteorological Agency).
Consequently, even supposing that global CO2 emissions were limited at thepresent level, and other conditions are presumed constant, in 74 years theconcentration for all GHGs would reach 475ppm and would continue to increase
after then as well. If the global CO2 emissions continue to increase as they are,475ppm will be reached sooner.
(Note 2) All GHGs: In the trial calculations for the AIM model, "all GHGs" takes into
account all factors (including both warming and cooling) with "radiative forcingthat causes" climate change, and expresses them as a carbon dioxide equivalence
concentration.
Specifically, in addition to the 6 gases that are the subject of the Kyoto Protocol(carbon dioxide [CO2], methane [CH4], nitrous oxide [N2O], hydrofluorocarbons[HFCs], perfluorocarbons [PFCs], and sulfur hexafluoride [SF6]), it also includes
the direct and indirect impacts of such things as chlorofluorocarbons (CFCs),
hydrochlorofluorocarbons (HCFCs), tropospheric ozone, and aerosols (sulfuric acidaerosol, black carbon, and organic carbon). Of these, sulfuric acid aerosol andorganic carbon, and others are considered to have a cooling effect.
Furthermore, although variations in solar radiation and the alteration of albedo (thereflectivity of solar radiation on earth surface and sea surface) due to changes inland use are among the changes since pre-industrial era, these factors are presumed
to have been constant since 1990. (Note: The contribution that variations in solar
radiation and changes in land use have made overall to the temperature increase at
the global level is insignificant.)(Note 3) This is equivalent to 456ppm for CO2 alone and 486ppm for all 6 gases that are thesubject of the Kyoto Protocol combined (as of the year 2100).

○

In order to arrive at a GHG concentration that limits the temperature rise to
below 2ºC, a major reduction of GHG emissions must be realized early on. For
example, according to trial calculations using the AIM model, the concentrationof all GHGs will need to be stabilized at 475ppm from the year 2030 onward inorder to limit the temperature increase to below 2ºC, and the calculations
indicate that, in comparison to the 1990 figures, all GHG emissions worldwide
will have to be reduced about 10% by the year 2020, about 50% by 2050, andabout 75% by 2100 (See Figure 6.3).

23

GHG concentrations (ppm, CO2 equivalent)

900
800
700
600
500
400
300

Social welfare function
maximized, discount 4%
Estimated rate of
reduction for the 6 gases
subject to the Kyoto
Protocol, plus CFCs,
HFCs, and HCFCs.

GHG emissions (GtC/year, CO2 equivalent)

Year

25

20

15

10

5

0

Year
BaU

GHG-475ppm

GHG-500ppm

GHG-550ppm

GHG-650ppm

Figure 6.3 AIM trial calculations for concentration stabilization levels andemission paths24

○ Furthermore, there is a need for future, more thorough study of the reduction
paths that will be necessary to achieve the GHG reductions. At such time it will
be necessary to consider how to deal with the uncertainty associated withclimate sensitivity and the like, and with disparities in the cost of
countermeasures due to the subject, timing, etc. There are analyses, etc. being
done that take uncertainty into account, but there is a need to move forward withfurther research (see Figure 6.4).

（

Source: Meinshausen (2005)15
Figure 6.4 Example of a trial calculation of the relationship between
concentration
stabilization and temperature increase, with uncertainty factored in
・ The probability that GHGs stabilized at 550ppm would cause a temperature increase of more than2ºC is high, at 68~99%.
・ In order to raise the probability to what IPCC terms "likely (66-90%)," that 2ºC will not be
exceeded, indications are that GHG stabilization would have to be at 400ppm (with GHGs at
450ppm, the probability cannot be raised that high).
・ Meinshausen shows the probabilities, for differing concentration stabilization targets, of the
post-industrialization temperature rise being limited to below 2ºC. It is characterized by its use ofprobability distribution for 8 climate sensitivities.

25

7. Agenda for the Future
7.1 Further Study concerning Long-Term Targets○ In dealing with long-term targets, it is necessary to give them some level offlexibility, while keeping in mind uncertainty inherent to projections; and thosetargets require, even after being set, continuing re-evaluation, responding tofurther fulfillment of scientific knowledge.
○ While it is important that Japan evaluate and establish long-term targets based on
its own national strategy, on the other hand, close observation of the situation ofvarious foreign countries is essential. For example, it is important to steadilycollect, consider and examine the information on long-term objectives oflimiting the temperature rise to 2ºC, such as the discussions in EU, tracking theirprogress, and looking into their scientific and strategic backgrounds.
○ Due to the call for political decisions and a strategy for Japan, the role of eachcountry in the globally sought reduction of greenhouse gas (GHG) emissions is a
topic for future study. In order to make progress in those evaluations from here
on, it is important to also deepen one’s knowledge of the costs and benefits, andspecific contents of necessary measures.
○ When the impacts on ecosystems and agriculture are considered, it is importantto take note of not only the degree of the rise in temperature but also the velocityof changes. For this reason, the study of rate of change is needed.

7.2 Risk Management of Climate Change○ Climate change may cause significant and irreversible impacts. Furthermore,global warming to some extent cannot be avoided due to the GHGs humankind
has thus far emitted. Based on the recognition of these facts, we are asking
ourselves the question of as to which levels the temperature rise should be26

limited, and to that end, which levels GHG concentrations must be controlled.
However, since climate change cannot be examined in a laboratory setting,uncertainty in scientific findings cannot be avoided.
○ In connection with this uncertainty, as long as the present socioeconomic activity
is valued highly, our concerns about the negative impacts feared for the futurewould be more focused on the probability of the disaster not taking place. On theother hand, should we be concerned with the need to avoid the impact of what isalready underway, we would be more interested in the probability of theoccurrence of this phenomenon. According to the precautionary principle
advocated in the United Nations Framework Convention on Climate Change,
which stipulates that "lack of full scientific certainty should not be used as areason for postponing precautionary measures" in consideration of irreversible
impacts, the latter probability must be weighed more heavily.
○ Moreover, it is necessary to keep in mind not only the adverse effects withrelatively high probability of occurrence from climate change, but in considering
uncertainties, also catastrophe events with a very low probability of occurrence.
○ In consideration of these points, policymakers are required to assume the role ofmaking decisions on matters filled with uncertainty. However, it is possible forscience to provide suggestions in that decision-making process. From this pointof view, the accumulation of knowledge and development of technologicalmethodology are important issues as they support the decision-making processof policies for the "risk management of global warming." Those issues include
such matters as "when and what steps have to be taken as adequate measures"and "how to balance mitigation and adaptation," based on progress in researchon the impacts and the timing at which the thresholds is exceeded.
○ The management of risks is an issue for the society at large and it is importantfor each person to share a scientific understanding, and to engage in intensifying
serious discussions about the optimal method for goal setting and the ideal way

27

of formulating measures in the future, based on common scientific knowledge.
Therefore, public agencies must work at further efforts to provide citizens withinformation and to promote discussions concerned.

7.3 Clarification of "the Effects of Climate Change" in the Context ofa Closely Integrated Global Economy○ Up until now, the concern for the effects of climate change has revolved around
territories. For instance in Japan, research was centered on the effects to its own
national land. However, agricultural and fishery products consumed in Japan,such as food and feed supply, for example, are imported from many areas of theworld, and, thus, the effects of climate change in those countries or regions oforigin also affect the people of Japan. From this point of view, it is necessary to
not only examine "the effects on Japan’s agriculture, forestry and fisheries
industries," but also the influence on Japan’s food supply.
○ This issue is more than a matter of Japan’s domestic concern. The UNFCCC's
ultimate objective "to ensure food production is not threatened" does not only
refer to the food production to fill the needs of people globally. In this closely
integrated world, the needs of each country and their people will not be filled
without trade. It is therefore critical to clarify the effects of climate change onfood supply over areas of production and those of consumption as one integrated
entity. Not limited to food production, in addition the effect must be examinedfrom a similar stance for other fields such as securing water resources and the
manufacture of industrial products.
○ From this perspective, it is one of the challenges of the future that we attempt toclarify the effects of climate change in a way fit for the reality of a closely
integrated global economy, while taking into consideration an international
interdependence. In particular, it is necessary to examine the impacts that theclimate change may bring upon international security and the countermeasuresagainst such impacts, including the possibility of conflicts among people and28among countries, arising from the threat to habitations and available water
resources.

29References
1) ACIA (Arctic Climate Impacts Assessment), 2004: Impacts of Warming Arctic.
140pp.
2) Parmesan, C. and H. Galbraith, 2004: Observed Impacts of Global Climate Change
in US. Pew Center Report, 56pp.
3) Stott, P.A., D. A. Stone and M. R. Allen, 2004: Human contribution to the European
heatwave of 2003, Nature, 432, 610-614.
4) International Scientific Steering Committee (ISSC), 2005: Report of theInternational Scientific Steering Committee, International Symposium on the
Stabilisation of greenhouse gas concentrations, Hadley Center, Exeter, UK.
http://www.stabilisation2005.com/Steering_Commitee_Report.pdf5) WWF, 2005: An Overview of Glaciers, Glacier Retreat, and Subsequent Impacts in
Nepal, India and China, 70pp.
6) Persing, J. and F. Tudela, 2003: A long-term target: Framing the climate effort. In“Beyond Kyoto: Advancing the international effort against climate change”.
Washington D.C., Pew Center on Global Climate Change, 15pp.
7) Parry, M., N. Arnell, T. McMichael, R. Nicholls, P. Martens, S. Kovats, M.
Livermore, C. Rosenzweig, A. Iglesias and G. Fischer, 2001: Millions at risk:
defining critical climate change threats and targets, Global Environmental Change,
11, 181-183.
8) O’Neil, B.C. and M. Oppenheimer, 2002: Climate change: dangerous climate
impacts and the Kyoto Protocol, Science, 296, 1971-1972.
9) Stocker, T. F. and A. Schmittner, 1997: Influence of CO2 emission rates on thestability of the thermohaline circulation. Nature, 388, 862-865.
10) Schlesinger, M., J. Yin, G. Yohe, N. Andronova, S. Malyshev, B.Li, 2005: Assessing
the risk of a collapse of the Atlantic Thermohaline Circulation, Abstracts of theInternational Symposium on Stabilization of greenhouse gas concentrations, Exeter,
UK.
11) Ministry of the Environment of Japan, Working Group on the Impacts of Global
Warming under the Commission on Global Warming, 2001: The Impacts of Global
Warming on Japan – 2001.
12) Matsui, T. et al., 2004: Probability distributions, Fagus crenata forests following
vulnerability and predicted climate sensitivity in changes in Japan. Journal of
Vegetation Science, 15, 605-614.

3013) Yokozawa, M., S. Goto, Y. Hayashi, and H. Seino, 2003: Mesh climate change data
for evaluating climate change impacts in Japan under gradually increasing
atmospheric CO2 concentration, Jour. Agri. Meteorol., 59(2), 117-130.
14) Fukuhara, N. and N. Mimura, 2004: Current Status of Study on Impacts based on the
Database of Global Warming Study, Proceedings of the 12th Symposium on Global
Environment.
15) Meinshausen, M., 2005: On the risk of overshooting 2oC, Abstract of theInternational Symposium on the Stabilization of greenhouse gas concentrations,Exeter, UK.

31

Attachment
Members of the Sub-Committee for International Climate Change Strategy
NAME○ Shuzo NISHIOKA

TITLE
Executive Director (Research)
National Institute for Environmental Studies

ASUKA-ZHANG

Professor, Center for Northeast Asian Studies

Shouchuan (Jusen)

Tohoku University

Mikiko KAINUMA

Chief
Integrated Assessment Modeling Section
National Institute for Environmental Studies

Yasuko KAMEYAMA

Senior Researcher
Social and Environmental Systems Division
National Institute for Environmental Studies

Hiroki KUDO

Group Manager
Environment/Energy Conservation GroupThe Institute of Energy Economics, Japan

Akimasa SUMI

Professor, Center for Climate System Research
University of Tokyo

Kazuo TAKAHASHI

Professor, Division of International Studies
International Christian University

Yukari TAKAMURA

Associate Professor (International Law)
Ryukoku University

Hidenori NIIZAWA

Professor, School of Economics
University of Hyogo

Hideo HARASAWA

Director
Social and Environmental Systems Division
National Institute for Environmental Studies

Ryuji MATSUHASHI

Professor, Institute of Environmental Studies
Graduate School of Frontier Sciences
University of Tokyo

Nobuo MIMURA

Professor, Center for Water Environment Studies
Ibaraki University

Yozo YOKOTA

Professor, Chuo Law School○ Chairperson32