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Footnotes
for the Summary for
Policymakers of IPCC
Working Group III
Source
& © : IPCC
TAR SPM of WG III
1
Mitigation is defined
here as an anthropogenic
intervention to reduce
the sources of greenhouse
gases or enhance their
sinks.
2
Climate change in IPCC
usage refers to any
change in climate over
time, whether due to
natural variability
or as a result of human
activity. This usage
differs from that in
the UNFCCC, where climate
change refers to a change
of climate that is attributed
directly or indirectly
to human activity that
alters the composition
of the global atmosphere
and that is in addition
to natural climate
variability observed
over comparable time
periods.
3
Section numbers refer
to the main body of
the Report.
4
In this report “alternative
development paths”
refer to a variety of
possible scenarios for
societal values and
consumption and production
patterns in all countries,
including but not limited
to a continuation of
today’s trends.
These paths do not include
additional climate initiatives
which means that no
scenarios are included
that explicitly assume
implementation of the
UNFCCC or the emission
targets of the Kyoto
Protocol, but do include
assumptions about other
policies that influence
greenhouse gas emissions
indirectly.
5
Approaches to equity
have been classified
into a variety of categories,
including those based
on allocation, outcome,
process, rights, liability,
poverty, and opportunity,
reflecting the diverse
expectations of fairness
used to judge policy
processes and the corresponding
outcomes (Sections 1.3,
10.2).
6
Emissions from all regions
diverge from baselines
at some point. Global
emissions diverge earlier
and to a greater extent
as stabilization levels
are lower or underlying
scenarios are higher.
Such scenarios are uncertain,
do not provide information
on equity implications
and how such changes
may be achieved or who
may bear any costs incurred.
7
Reserves are those occurrences
that are identified
and measured as economically
and technically recoverable
with current technologies
and prices. Resources
are those occurrences
with less certain geological
and/or economic characteristics,
but which are considered
potentially recoverable
with foreseeable technological
and economic developments.
The resource base includes
both categories. On
top of that, there are
additional quantities
with unknown certainty
of occurrence and/or
with unknown or no economic
significance in the
foreseeable future,
referred to as “additional
occurrences” (SAR,
Working Group II). Examples
of unconventional fossil
fuel resources include
tar sands, shale oil,
other heavy oil, coal
bed methane, deep geopressured
gas, gas in acquifers,
etc.
8
“Known technological
options” refer
to technologies that
exist in operation or
pilot plant stage today,
as referenced in the
mitigation scenarios
discussed in this report.
It does not include
any new technologies
that will require drastic
technological breakthroughs.
In this way it can be
considered to be a conservative
estimate, considering
the length of the scenario
period.
9
Ancillary benefits are
the ancillary, or side
effects, of policies
aimed exclusively at
climate change mitigation.
Such policies have an
impact not only on greenhouse
gas emissions, but also
on resource use efficiency,
like reduction in emissions
of local and regional
air pollutants associated
with fossil fuel use,
and on issues such as
transportation, agriculture,
land-use practices,
employment, and fuel
security. Sometimes
these benefits are referred
to as “ancillary
impacts” to reflect
that in some cases the
benefits may be negative.
10
In
this report, as in the
SAR, no regrets opportunities
are defined as those
options whose benefits
such as reduced energy
costs and reduced emissions
of local/regional pollutants
equal or exceed their
costs to society, excluding
the benefits of avoided
climate change.
11
A voluntary agreement
is an agreement between
a government authority
and one or more private
parties, as well as
a unilateral commitment
that is recognized by
the public authority,
to achieve environmental
objectives or to improve
environmental performance
beyond compliance.
12
Many other studies incorporating
more precisely the country
specifics and diversity
of targeted policies
provide a wider range
of net cost estimates
(Section 8.2.2).
13
Annex II countries:
Group of countries included
in Annex II to the UNFCCC,
including all developed
countries in the Organisation
of Economic Co-operation
and Development.
14
Annex B countries:
Group of countries included
in Annex B in the Kyoto
Protocol that have agreed
to a target for their
greenhouse gas emissions,
including all the Annex
I countries (as amended
in 1998) but Turkey
and Belarus.
15
Many metrics can be
used to present costs.
For example, if the
annual costs to developed
countries associated
with meeting Kyoto targets
with full Annex B trading
are in the order of
0.5% of GDP, this represents
US$125 billion (1000
million) per year, or
US$125 per person per
year by 2010 in Annex
II (SRES assumptions).
This corresponds to
an impact on economic
growth rates over ten
years of less than 0.1
percentage point.
16
Induced technological
change is an emerging
field of inquiry. None
of the literature reviewed
in TAR on the relationship
between the century-scale
CO2 concentrations and
costs, reported results
for models employing
induced technological
change. Models with
induced technological
change under some circumstances
show that century-scale
concentrations can differ,
with similar GDP growth
but
under different policy
regimes (Section 8.4.1.4).
17
See Figure SPM.1 for
the influence of reference
scenarios on the magnitude
of the required mitigation
effort to reach a given
stabilization level.
18
Spillover effects incorporate
only economic effects,
not environmental effects.
19
Details of the six studies
reviewed are found in
Table 9.4 of the underlying
report.
20
These estimated costs
can be expressed as
differences in GDP growth
rates over the period
2000–2010. With
no emissions trading,
GDP growth rate is reduced
by 0.02 percentage points/year;
with Annex B emissions
trading, growth rate
is reduced by less than
0.005 percentage points/year.
21
These policies and measures
include: those for non-CO2
gases and non-energy
sources of all gases;
offsets from
sinks; industry
restructuring (e.g.,
from energy producer
to supplier of energy
services); use of OPEC’s
market power; and actions
(e.g. of Annex B Parties)
related to funding,
insurance, and the transfer
of technology. In addition,
the studies typically
do not include the following
policies and effects
that can reduce the
total cost of mitigation:
the use of tax revenues
to reduce tax burdens
or finance other mitigation
measures; environmental
ancillary benefits of
reductions in fossil
fuel use; and induced
technological change
from mitigation policies.
22
Carbon leakage is defined
here as the increase
in emissions in non-Annex
B countries due to implementation
of reductions in Annex
B, expressed as a percentage
of Annex B reductions.
Source
& © : IPCC
TAR SPM of WG III
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