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REPORTS - ASSESSMENT REPORTS |
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Synthesis Report - Question 1
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Climate Change 2001: Synthesis Report |
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| 1.6
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With regard to strategies
for addressing climate change, the TAR provides an assessment of the potential
for achieving different levels of concentrations through mitigation and
information about how adaptation can reduce vulnerability. The causality
works in both directions. Different stabilization levels result from different
emission scenarios, which are connected to underlying development paths.
In turn, these development paths strongly affect adaptive capacity in
any region. In this way adaptation and mitigation strategies are dynamically
connected with changes in the climate system and the prospects for ecosystem
adaptation, food production, and sustainable economic development.
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WGII TAR Chapter 18 & WGIII
TAR Chapter 2 |
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An integrated view of climate change considers the dynamics of the
complete cycle of interlinked causes and effects across all sectors
concerned. Figure 1-1 shows the cycle,
from the underlying driving forces of population, economy, technology,
and governance, through greenhouse gas and other emissions, changes
in the physical climate system, biophysical and human impacts, to adaptation
and mitigation, and back to the driving forces. The figure presents
a schematic view of an ideal "integrated assessment" framework,
in which all the parts of the climate change problem interact mutually.
Changes in one part of the cycle influence other components in a dynamic
manner, through multiple paths. The TAR assesses new policy-relevant
information and evidence with regard to all quadrants of Figure
1-1. In particular, a new contribution has been to fill in the bottom
righthand quadrant of the figure by exploring alternative development
paths and their relationship to greenhouse gas emissions, and by undertaking
preliminary work on the linkage between adaptation, mitigation, and
development paths. However, the TAR does not achieve a fully integrated
assessment of climate change, because of the incomplete state of knowledge.
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WGII TAR Chapters 1 & 19,
WGIII TAR Chapter 1, &
SRES
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| 1.8
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Climate change decision
making is essentially a sequential process under general uncertainties.
Decision making has to deal with uncertainties including the risk of non-linear
and/or irreversible changes and entails balancing the risk of eitherinsufficient
or excessive action, and involves careful consideration of the consequences
(both environmental and economic), their likelihood, and society's
attitude towards risk. The latter is likely to vary from country to country
and from generation to generation. The relevant question is "what
is the best course for the near term given the expected long-term climate
change and accompanying uncertainties."
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WGI TAR, WGII
TAR, & WGIII TAR Section
10.1.4 |
1.9
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Climate change impacts
are part of the larger question of how complex social, economic, and environmental
subsystems interact and shape prospects for sustainable development.
There are multiple links. Economic development affectsecosystem balance
and, in turn, is affected by the state of the ecosystem; poverty can be
both a result and a cause of environmental degradation; material- and
energy-intensive life styles and continued high levels of consumption
supported by non-renewable resources and rapid population growth are not
likely to be consistent with sustainable developmentpaths; and extreme
socio-economic inequality within communities and between nations may undermine
the social cohesion that would promote sustainability and make policy
responses more effective. At the same time, socio-economic and technology
policy decisions made for non-climate-related reasons have significant
implications for climate policy andclimate change impacts, as well as
for other environmental issues (see Question 8).
In addition, critical impact thresholds and vulnerability to climate change
impacts are directly connected to environmental, social, and economic
conditions and institutional capacity.
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WGII TAR |
1.10
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As a result, the effectiveness of climate policies
can be enhanced when they are integrated with broader strategies designed
to make national and regional development paths more sustainable.
This occurs because of the impacts of natural climate variation and changes,
climate policy responses, and associated socio-economic development will
affect the ability of countries to achieve sustainable development goals,
while the pursuit of those goals will in turn affect the opportunities
for, and success of, climate policies. In particular, the socio-economic
and technological characteristics of different development paths will
strongly affect emissions, the rate and magnitude of climate change, climate
change impacts, the capability to adapt, and the capacity to mitigate
climate. The Special Report on Emissions Scenarios (SRES, see
Box 3-1) outlined multiple plausible
future worlds with different characteristics, each having very different
implications for the future climate and for climate policy.
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WGIII TAR Section 10.3.2 |
| 1.11 |
The TAR assesses available
information on the timing, opportunities, costs, benefits, and impacts of
various mitigation and adaptation options. It indicates that there
are opportunities for countries acting individually, or in cooperation with
others, to reduce costs of mitigation and adaptation and realize benefits
associated with achieving sustainable development.
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WGII TAR Chapter 18, WGIII
TAR Chapters 8, 9, & 10,
& SRES |
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Figure 1-1: Climate
change- an integrated framework. Schematic and simplified
representation of an integrated assessment framework for considering anthropogenic
climate change. The yellow arrows show a full clockwise cycle of cause and
effect among the four quadrants shown in the figure, while the blue arrow
indicates the societal response to climate change impacts. For both developed
and developing countries, each socio-economic development path
explored in the Special Report on Emissions Scenarios has driving forces
which give rise to emissions of greenhouse gases, aerosols, and precursors -- with
carbon dioxide (CO2 ) being the most important. The greenhouse
gas emissions accumulate in the atmosphere, changing concentrations
and disturbing the natural balances, depending on physical processes
such as solar radiation, cloud formation, and rainfall. The aerosols also
give rise to air pollution (e.g., acid rain) that damage human and the natural
systems (not shown). The enhanced greenhouse effect will initiate climate
changes well into the future with associated impacts on
the natural and human systems. There is a possibility of some feedback
between the changes in these systems and the climate (not shown), such as
albedo effects from changing land use, and other, perhaps larger, interactions
between the systems and atmospheric emissions (e.g., effects of changes
in land use (again not shown)). These changes will ultimately have effects
on socio-economic development paths. The development paths also have direct
effects on the natural systems (shown by the anti-clockwise arrow from the
development box) such as changes in land use leading to deforestation. This
figure illustrates that the various dimensions of the climate change issue
exist in a dynamic cycle, characterized by significant time delays. Both
emissions and impacts, for example, are linked in complex ways to underlying
socio-economic and technological development paths. A major contribution
of the TAR has been to explicitly consider the bottom righthand domain (shown
as a rectangle) by examining the relationships between greenhouse gas emissions
and development paths (in SRES),
and by assessing preliminary work on the linkage between adaptation, mitigation,
and development paths (WGII
and WGIII). However, the
TAR does not achieve a fully integrated assessment of climate change, since
not all components of the cycle were able to be linked dynamically. Adaptation
and mitigation are shown as modifying the effects shown in the figure. |
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