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Natural, technical, and social sciences can provide
essential information and evidence needed for decisions on what constitutes
"dangerous anthropogenic interference" with the climate system. At the
same time, such decisions are value judgments determined through socio-political
processes, taking into account considerations such as development, equity,
and sustainability, as well as uncertainties and risk. Scientific
evidence helps to reduce uncertainty and increase knowledge, and can serve
as an input for considering precautionary measures.1
Decisions are based on risk assessment, and lead to risk management choices
by decision makers, about actions and policies.2 |
WGII TAR Section 2.7 & WGIII TAR Chapter 10 | |||||
The basis for determining what constitutes "dangerous
anthropogenic interference" will vary among regions, depending both
on the local nature and consequences of climate change impacts, and
also on the adaptive capacity available to cope with climate change.
It also depends upon mitigative capacity, since the magnitude and the
rate of change are both important. The consequent types of adaptation
responses that will be selected depend on the effectiveness of various
adaptation or mitigation responses in reducing vulnerabilities and improving
the sustainability of life-support systems. There is no universally
applicable best set of policies; rather, it is important to consider
both the robustness of different policy measures against a range of
possible future worlds, and the degree to which such climate-specific
policies can be integrated with broader sustainable development policies.
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WGII TAR Chapter 18 & WGIII TAR Chapter 10 | |||||
The Third Assessment Report (TAR) provides an assessment
of new scientific information and evidence as an input for policy makers
in their determination of what constitutes "dangerous anthropogenic interference
with the climate system" with regard to: (1) the magnitudes and rates
of changes in the climate system, (2) the ecological and socio-economic
impacts of climate change, and (3) the potential for achieving a broad
range of levels of concentrations through mitigation and information about
how adaptation can reduce vulnerability. |
WGI TAR, WGII TAR, & WGIII TAR | |||||
1.4 |
With regard to the magnitudes and rates of changes in
the climate system, the TAR provides scenario-based projections of future
concentrations of greenhouse gases in the atmosphere, global and regional
patterns of changes and rates of change in temperature, precipitation,
and sea level, and changes in extreme climate events. It also examines
possibilities for abrupt and irreversible changes in ocean circulation
and the major ice sheets. |
WGI TAR | ||||
1.5 |
The TAR reviews the biophysical and socio-economic impacts of climate change. The TAR articulates five reasons for concern, regarding:
Of great significance here is an assessment of the likelihood of the critical thresholds at which natural and human systems exhibit large-scale, abrupt, or irreversible changes in their response to a changing climate. Since no single indicator (e. g., a monetary unit) captures the range of relevant risks presented by climate change, a variety of analytical approaches and criteria are required to assess impacts and facilitate decisions about risk management. |
WGII TAR Chapter 19 |
Other reports in this collection |