Action and ambition for a global deal in Copenhagen

Action and ambition for a global deal in
Copenhagen
Nicholas Stern
6th December 2009
Centre for Climate Change Economics and Policy
Grantham Research Institute for Climate Change and
the Environment
In collaboration with the
United Nations Environment Programme (UNEP)
Policy Update
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Action and Ambition for a Global Deal in Copenhagen1
Summary:
This paper sets out an assessment of the latest national positions regarding
emission reduction targets and actions going into the forthcoming negotiations
in Copenhagen. These targets and intentions are quantified and translated
into global emissions to give an understanding of how close we are to a
possible agreement consistent with keeping temperature increase below 2°C.
Recent work on the latest science and economics of 2°C shows that global
emissions should be around 44Gt2 carbon dioxide equivalents in 2020 to be
consistent with a 50-50 chance of keeping temperature increase below 2°C.
This is in line with the earlier work that underpins the IPCC conclusions.
Existing proposals from developed and developing countries, if delivered,
constitute a big step towards a path consistent with the 2°C goal. Taking
countries’ highest intentions would take the world to around 46Gt in 2020 a
gap of 2Gt, which may be around 80% of the way from business as usual,
depending on the interpretation of business as usual.
However, this analysis relies on the following key assumptions:
• Countries moving to or standing by their high intentions which may require
the satisfaction of stipulated conditions concerning action from others
• Providing adequate finance and other support for high intentions in
developing countries such as Indonesia and Brazil; this should not count
offset finance, as this risks double counting, or with offset finance but
matched with more stringent targets.
• That surplus emissions allowances from previous commitment periods do
not weaken mitigation effort
• A system of rules for how to account for the emissions released and
absorbed in the LULUCF sector (Land Use, Land Use Change and
Forestry) to ensure the environmental integrity of emission targets
But with the right kind of collaborative spirit it is clearly possible for countries
to get to together so that the necessary strong commitments can be made.
Analysing these intentions often relies on relating targets and actions to a
concept of business as usual (BAU). BAU is a concept that is difficult to pin
down because a group of polices that have been indicated or announced may
or may not be included in BAU; further it can depend on what assumptions are
made about structural change, for example how rapidly services grow as a
share of the economy. Where an analyst uses a higher estimate of business
as usual this can lead to a larger estimated gap. It also depends on what is
included in these estimates and with significant uncertainty around current
and future non-energy emissions there is scope for alternative estimates. We
1 This is a work in progress incorporating announcements as of 4th December and subject to
revision as many country plans are under review and could to change or be clarified, so this
assessment will be subject to change. The interpretation of the targets are the authors. Many
thanks to Chris Taylor and colleagues at the Grantham Research Institute, LSE and at UNEP
for their helpful comments and guidance. Comments are very welcome.
2 Gigatonne - which is a billion tonnes
suggest an uncertainty range of around -1Gt to +3Gt3 around our estimate of
the gap.
On the basis of the above calculations the gap would be 2Gt (range from 1Gt
to 5Gt). Filling the remaining 2Gt gap would require greater ambition
(especially from larger emitters in order to deliver required reductions), ideally
combined with a contribution to emission reductions from international aviation
and maritime sectors which is currently excluded from existing commitments,
and greater efforts on REDD.
While there is much to do, we should not downplay how close we are to
delivering an effective and credible global agreement.
What is a ‘climate responsible’ trajectory?
Research4 by the LSE Grantham Research Institute explored a range of
trajectories that result in a reasonable chance of keeping temperature
increases below 2°C and considered the economic implications. Annex 1
provides a more detailed summary. The scientific conclusions are consistent
with the ranges in the IPCC. Since it is cumulative emissions over time that
matter most to eventual temperature increase, less early action means more
costly and sharper reductions to lower emission levels in the future.
The analysis concludes that emissions should be around 44Gt in 2020,
representing a sensible “climate responsible” target from a cost and risk
management perspective5. Lower emissions would also be consistent with
2°C but require very strong action over the next decade. Higher emissions
could still reach the same climate outcomes but require more drastic action
after 2020 that would be considerably more expensive and may not be
feasible. Current emissions are around 47Gt in 2010 (this would be close to
50Gt if it were not for the slowdown).
But how do current intentions collectively compare to 44Gt in 2020? The next
section outlines and quantifies the commitments, targets, proposals and
intentions of the major emitters6. It does not cover the plans for other
countries although many of them are ambitious relative to their size such as
Norway’s commitment to reduce emissions by 40% on 1990 levels and the
Maldives pledge to be carbon neutral by 2019.
3 This range is skewed to reflect the fact that we are unable to include peat emissions which
could currently be around 1Gt to 1.5Gt. Other studies evaluating current intentions can be
found at http://www.climateactiontracker.org/ and http://www.project-catalyst.info/
4 Paper released on 1st December by Dr Ranger and Dr Bowen on the Grantham Research
Institute website.http://www2.lse.ac.uk/granthamInstitute/pdf/bowenRangerPolicyBrief.pdf
5 There is not as yet wide political agreement that such a level is an appropriate benchmark
for a 2°C trajectory. However, in our view this represents an appropriate level for this analysis.
6 At the time of writing the countries in the more detailed tables are all in the top 20 carbon
dioxide emitters and collectively account for more than 80% of global emissions Emission
commitments excluded from the detailed tables are included in the overall numbers for
developed countries..
Current developed country proposals
Table 1: Annex I - developed countries
Country Description Summary for
2020 emissions
US Recent announcement that the US is prepared to table
an emissions commitment of 17% below 2005 levels
(3% below 19907). Longer-term goals set out a pathway
to an 83% below 2005 levels (80% reduction below
1990 levels) in 2050. Earlier draft legislation had
additional provisions to buy 0.7Gt of forestry credits in
2020 and around $3bn for technology and adaptation.
Currently emissions are 15% above 1990 levels.
3% below 1990
levels
Plus support for
reduced
deforestation?
EU Committed to reduce emissions to 20% below 1990
levels (currently 12.5% below) and 30% below 1990
levels as part of an ambitious global agreement.
Indicated willingness to pay its share of significant
finance flows from developed to developing countries
including public finance that could support additional
mitigation (including REDD).
20 to 30% below
1990 levels.
Public finance for
additional
mitigation
elsewhere
Japan Japan has committed to reduce emissions by 25%
below 1990 levels as part of an effective and
comprehensive agreement at COP 15.
25% below 1990
levels
Russian
Federation
Russian Federation committed to reduce emissions by
up to 25% below 1990 levels. Russian emissions were
36% below 1990 levels in 2007.
25% below 1990
levels
Canada Committed to reduce emissions by 20% relative to 2006
levels (equivalent to 3% below 1990)
3% below 1990
levels
Australia Australia proposed to reduce its emissions to 5-25%
below 2000 levels (15% to 33% below 1990 levels).
Adoption of the most ambitious target of 25% depends
on five conditions being met8. If not all the conditions are
met but there is an international agreement with all
major emitters the target would be -15%.
15% to 33%
below 1990
levels
Based on authors understanding of existing positions
Some of the intentions have not yet been legislated as national commitments
or action plans and others are reliant on particular conditions being met (e.g.
on international agreement). Direct quantification of developed country targets
is often straightforward as they are related to fixed historical emissions levels
(although they tend to get complicated over how emissions and emissions
reductions in land use change, afforestation, reforestation and land
degradation will affect the target and the degree to which it is intended that
international offset credits play a role).
For Tables 1 and 2 we have used emissions excluding LULUCF. In 2005
UNFCCC data suggests that Annex I countries provided a net sink of around
1.8Gt which would further reduce emissions so excluding it from this analysis
7 The 3% figure is based on a 17% reduction of emissions excluding LULUCF. The target was
announced based on emissions including LULUCF which would be 5.5% on 1990 emission
including LULUCF. Depending on the accounting rules this is could be equivalent to about a
5% reduction on 1990 emission excluding LULUCF.
8 http://unfccc.int/files/kyoto_protocol/application/pdf/australia010609.pdf reductions on 1990
levels based on recently revised UNFCCC 1990 data and including LULUCF in line with
Australian targets
ignores the potential additional contribution they could make. It is excluded as
its treatment is dependent in international rules which have yet to be
determined. If it is used to meet targets it could reduce mitigation effort from
other sources and possibly increasing emission levels beyond the totals in the
next table. The table also excludes the potential for surplus credits from
previous commitment periods being used to meet targets which, if permitted,
could increase emissions in 2020.
Table 2: Current developed country proposals in 2020 (Gt CO2e)
Low intentions
2020 Emissions
(Gt) High intentions
2020 Emissions
(Gt)
US -17% on 2005 5.9 -17% on 2005 5.9
EU -20% on 1990 4.5 -30% on 1990 3.9
Japan -25% on 1990 1.0 -25% on 1990 1.0
Other developed countries 5.1 5.0
Developed country total 16.3 15.7
So current proposals would take developed countries to around 16Gt (and a
significant deviation from business as usual) and around 16% below 1990
levels. It is not possible to determine whether such commitments are enough
to take the world onto a 44Gt pathway until it is combined with developing
country actions; and it would remain open to debate whether it represents an
equitable share of the mitigation effort.
Targets and actions announced by developing countries
Table 3: Non-Annex I - developing countries
Country Description 2020 Summary
China Announced policies such as the energy intensity
target in the current 5 year plan and 2020 targets
for renewable and nuclear are set to reduce
emissions by around 10% below business as
usual (BAU). Recent announcement to set
carbon intensity of output to 40% to 45% below
2005 levels by 2020.
Carbon intensity
target and
existing domestic
policies lead to a
10% reduction on
2020 BAU
India Plans and policies outlined in National Plan and
in the 11th 5 year plan. Many are not quantified
but domestic policy initiatives with policy targets
collectively amount to a deviation from BAU of at
least 7%. Recent announcement to set carbon
intensity of output to 20% to 25% below 2005
levels by 2020.
Carbon intensity
target and
existing domestic
policies lead to at
least 7%
reduction on
2020 BAU
Brazil Announced target reduce its emissions by 36%
to 39% on 2020 BAU levels (roughly 1/3 below
1990 levels) conditional on external financing
and including significant REDD. Level of finance
requirements not yet clear so not certain what is
own action and what requires support. Had
previously announced a National Action Plan
that would reduce emissions by about 25%
below BAU.
36% to 39%
below 2020 BAU
levels with
external financial
support
Indonesia Pledged to reduce emissions below BAU by 26%
unilaterally and 41% below with international
26% below 2020
BAU unilateral,
support (around 1/6 to 1/3 below 1990 levels).
The 26% target is to be achieved primarily
through reduced emissions from deforestation
and land use change.
41% below
conditional
South Korea Unilateral pledge to reduce emissions by 30%
below their defined BAU (around 4% below 2005
levels).
30% below 2020
BAU
South Africa Existing domestic policies expected to reduce
emissions by about 10% from BAU. Government
intention to follow a peak and decline scenario
which allows for the initial build-up of base-load
capacity, would equate to around 20% below
BAU levels.
10% below 2020
BAU
Mexico National plan (PECC) sets out detailed policies
up to 2012 that are being enacted which are
likely to reduce emission by around 5% in 2020
relative to BAU. Overall strategy to reduce
emissions by 50% by 2050 implies emission
being around 20% below BAU in 2020.
5% below 2020
BAU but longer
term goals imply
greater ambition
Note: Based on authors understanding of existing positions. Where countries have
announced both a set of policies and a carbon intensity (or other) reductions we have taken
the bigger of the two calculations in terms of reductions. This is of particular relevance to
China and India where the announced intensity targets appear to imply lower than the
reductions that would follow from announced policies (perhaps because there is some
inherent caution on the implementation of the policies).
Again some of the intentions have not yet been legislated as national targets
or action plans and others are reliant on certain conditions being met. This is
particularly the case for Indonesia and Brazil where delivering on the high
ambition targets is dependent on international support. As countries have
expanded their scale of ambition they are understandably looking again at
what support would be required. This highlights the importance of developed
countries delivering substantial financial resources to support the willingness
of some developing countries to implement ambitious policies.
Targets in developing countries pose additional challenges for quantification.
The targets are usually related to business as usual9 (BAU) – the path
emissions would be likely to follow without further policy action. Reductions
are therefore dependent on what assumptions are made about the BAU path.
This is easier where countries specify reductions against a specified BAU but
where they do not there can be significant variations in BAU estimates from
9 There remains considerable uncertainty around developing country emissions and, in
particular those relating to forestry and land use. The uncertainty in developed country BAU is
much lower as targets are generally related to fixed historical points. Developing countries
would commit to actions relative to a definition of business as usual. They would be
committing to actions not the emission levels set out in this numerical exercise so this would
introduce some uncertainty in climate outcomes were significant revisions in BAU to occur.
Moreover, business as usual is a slippery concept that is inherently subjective and subject to
significant uncertainties. What actions and commitments are included in BAU over time is
subjective. It is easier where countries have specified actions against a defined path but other
sources of estimates of BAU (largely the International Energy Agency) are used for our
calculations where this is not possible. It is better, given its subjectivity, to avoid using BAU
where possible. Indeed by combining growth rates, emissions per unit of output and
associated mitigation actions, BAU becomes redundant.
different sources. Higher BAU estimates due to stronger economic growth,
energy intensity or LULUCF sources would affect to estimates of emission
outcomes.
The quantification of reductions in this analysis is predicated on the support
provided action to reach higher targets (e.g. Brazil and Indonesia) being
accomplished through public finance from developed countries, not carbon
market offsets (which would count towards the developed country target) in
order to avoid double counting. Offsets by developed countries would shift the
balance of actual emissions and would imply finance flows to developing
countries. We must be transparent about ‘adding up’ and avoid double
counting, and thus estimate actual emissions after offsets; emissions in
country A which buys the offsets are increased relative to the numbers here
and emissions in country B which receives the finance flow are lowered (sells
the offset). Nevertheless offsets through the carbon market can be a win-win
for both developed and developing countries10.
As a first step Table 4 considers only India and China’s domestic policy
targets and assumes other developing countries follow a BAU trajectory.
Table 4: Developing country policies (China and India) and the expected
emission reductions11 See note for Table 3
Country Current policies
Savings in 2020
(GT CO2e)
Emissions in
2020 (GT CO2e)
Energy Intensity target 20% by 2010 0.5
Renewable energy 15% by 2020 0.5
Nuclear target 75GW by 2020 0.3
Total 11.2
Solar Mission 20GW by 2020 0.03
Renewable electricity 15% by 2020 0.07
Increasing forest cover 6 million hectares by 2017 0.07
Total 3.6
Other developing countries 16.7
International aviation and maritime 1.3
Total developing countries and international aviation and maritime 32.8
China
India
Carbon intensity targets pose additional challenges to quantification. Growth
rates are already a key determinant in BAU but directly affect the total
10 They can provide private finance to foster both the transformation of the energy system in
developing countries and the transfer of and domestic development of low-carbon
technologies; and they can reduce global mitigation costs.
11 Estimates in this table are sensitive to uncertainty in business as usual. These estimates
are based on assumptions on developing country forestry and energy emissions that are
subject to a high degree of uncertainty. Changes in these levels will affect the volume of
emission reductions that would need to be delivered. Anthropogenic emissions from peat are
excluded and incorporating these would add up to 1.5Gt globally. This would provide an
additional argument to go further in mitigation action including specific action to reduce
emissions from peat to take advantage of these additional mitigation opportunities. Recent
revisions in deforestation estimates may offset incorporating peat emissions to an extent.
There should also be increased efforts to clarify current and hence likely future emissions to
reduce this uncertainty.
emissions implied by carbon intensity targets. In this analysis it was assumed
that China continued strong economic growth of over 8% but that existing
domestic policies (emissions intensity target up to 2010 and 2020 nuclear and
renewable targets) led to significant emission reductions on BAU. Our
analysis suggests this leads to lower emissions than implied by the emission
intensity target and hence it is the domestic targets that ‘bite’12 for the purpose
of these calculations. The same also applies to India’s emission intensity
target.
The following graph provides estimates of some of the emission reductions
from some of the targets proposed recently by Indonesia, Brazil, and South
Korea along with those implicit in South African modelling13. Thus the
reductions are additional to those in Table 4. In the case of Brazil they reflect
a crude estimation of the share of the target that is “national effort” and the
share that is conditional on additional support14.
If these actions and targets were fully supported allowing Brazil and Indonesia
to go to the top end of their targets but without using offset finance (which
would lead to double counting) then they would deliver an additional 2.6Gt
mitigation relative to Table 4 taking the other developing countries down to
14.2Gt and the total developing country emissions to 28.9Gt.
12 This would imply China did not abandon or loosen existing domestic policies and targets. If
economic growth was not as strong (i.e. below 6.5% per annum) then the emission intensity target
would start to reduce emissions further. If growth was significantly stronger than has been assumed
then this would push emissions up.
13 Long Term Mitigation Scenarios (LTMS). Strategic Options for South Africa. Pretoria, South
Africa: Development of Environment Affaires and Tourism (2007)
14 As reflected by the graded shading and arrow in the figure below.
Where could these commitments, actions and targets take the world?
These tables show that all the major emitters have shown a willingness to
take significant action to reduce their emissions from business as usual
(BAU), whilst specific targets reflect a diverse range of national
circumstances. The intentions and actions embodied in Tables 2, 4 and from
recent developing country intentions are shown in Table 5 and show that high
intentions imply global emissions of just under 46Gt in 2020. This figure
is derived from the high end of the developed country commitments and
reductions achieved in developing countries with adequate international
financial support (if not using offset credits). The gap relative to 44Gt in 2020
would be around 2Gt15 (or a range of 1Gt to 5Gt). This already represents a
saving of around 8Gt on BAU16 so existing announcements would, if
delivered, achieve 80% of the reductions that are required.
Table 5: Total emissions from high intentions
2020 total from
high intentions
Developed country total 15.7Gt
Developing countries total 28.9Gt
International aviation and maritime 1.3Gt
Global total 46Gt
Gap 2Gt
However, these estimates rely on countries being satisfied that the conditions
are met for them to reach high targets and, in particular, adequate support
being provided to developing countries to facilitate their highest intentions.
Strong financial and technical support is essential to deliver these
targets. Furthermore it assumes that double counting through offsets is
avoided and that there is no weakening of new targets through lax accounting
rules for the LULUCF or surplus emissions allowances from the Kyoto period.
Failure on these, or countries resorting to low intentions has the potential to
significantly reduce the overall level of ambition calculated here. Clearly there
are significant challenges involved in delivering such reductions but none of
these are insurmountable and the required reductions could probably be
achieved using current technologies and carefully designed policies.
Technological progress would open up a further range of options.
Filling the gap
There are many ways in which the remaining gap could be filled and it is
essentially a political question to be addressed by countries during the
upcoming COP negotiations. The main options include some combination of:
• Developed countries increasing their high intentions.
• Other developing countries, especially larger emitters (given their size),
coming forward with plans for further domestic reductions as part of a
15 Or 3.5Gt if anthropogenic peat emissions continue at current levels to 2020
16 Our business as usual (excluding peat) is 54Gt in 2020
global deal and/or an indication of what they could do with international
support.
• Additional reductions in deforestation and other sources
• Incorporating international emissions from aviation and maritime to
deliver additional mitigation17.
Conclusions
This analysis shows that existing developed and developing country targets
and plans can take us most of the way to global emissions of 44Gt in 2020,
which is consistent with a 2°C trajectory. This assumes that developed
countries provide finance to support mitigation in developing countries that is
not counted as an offset against their mitigation goals (or represents part of
more ambitious goals). It shows that agreeing actions consistent with a 2°C
trajectory is feasible in Copenhagen.
This analysis relies on two key assumptions if such a positive vision is to
come to fruition. First it assumes that countries are at least able to fully deliver
on their stated high intentions and that some of them increase their intentions
further. Given that many of these intentions are already ambitious the effort
required to deliver should not be understated. Starting strongly on a lowcarbon
path is surely justified relative to the dire consequences of the
alternative, but requires a radical restructuring of how our economies work in
the coming decades. Secondly it requires countries to come together and
agree to deliver on their intentions and provide the appropriate support to
each other to ensure that in Copenhagen we enshrine these intentions as part
of an international agreement.
Uncertainty in business as usual (BAU) could lead to larger estimates of the
‘gap’ if a higher BAU is included or estimates from peat and other LULUCF
sources are thought to be higher. This leads us to suggest a range for the gap
of 1Gt to 5Gt.
The countries of the world have made considerable progress towards
securing a global agreement that delivers emission reductions which are
commensurate with the scale of the challenge. All of the major economies
understand that every country must act. We must now work together to
cement and increase the indicative ambition shown thus far and turn this into
a solid set of actions and commitments that will fill the gap and deliver the
scale of reductions that are required to keep the temperature increase to
below 2°C. The people and politicians of the world, community by community,
nation by nation, will now determine whether we can create and sustain the
international vision, commitment and collaboration which will allow us to seize
this historic special opportunity and to rise to the challenge of a planet in peril.
17 For example, if we set a target of 20% below 2005 levels for international aviation and
maritime emissions this would lead to around 0.5Gt of additional mitigation (if any offsets that
were purchased were additional to current targets developed countries).
48GtCO2e
44GtCO2e
40GtCO2e
Annex 1: Defining 2020 emissions for a 2°C goal.18
Trajectories that have a reasonable chance of keeping temperature rise
to below 2°C
There are numerous trajectories that achieve similar climate outcomes. Since
it is cumulative emissions over time that matter most, less early action means
sharper reductions to low emission levels in the future. There are paths with
emissions below 40Gt in 2020 that are consistent with 2°C but are ignored as
they require global reduction above 2% per annum on average from 2010 to
2020, which is not considered credible given existing structures of production.
Trajectories nearer the top of the range in 2020 have to be near the bottom of
the 2050 range and vice versa.
Figure 1: Trajectories that give a reasonable chance of temperature rise
below 2°C19
Climate responsible trajectories
A “climate responsible” trajectory is one that has a reasonable chance of
avoiding expected temperature increases of more than 2°C, without entailing
excessive costs or risks. Current leaders and policy makers are responsible
for making a credible start on this trajectory, laying the foundations for greater
reductions in the future while not missing low-cost opportunities and not
passing much greater costs to future generations. The key points that define a
trajectory and hence “climate responsibility” are:
• Emission peak – the sooner and lower the peak in emissions, the smaller
the reductions that are required in the future. But it takes time to build the
18 For more see: http://www2.lse.ac.uk/granthamInstitute/pdf/bowenRangerPolicyBrief.pdf
19 These results are based on the Hadley Centre climate model MAGICC. There are some key uncertainties. The
majority of this uncertainty is in the response of the Earth’s system to human GHG emissions and comes from the
carbon-cycle feedback, with a smaller contribution from climate sensitivity. This uncertainty, of the order of +5 to
-10 Gt (skewed to negative) or more, suggests the need for lower targets to maintain the option to revise
downwards if new science warrants stronger action. For 2050, around ±4GtCO2e uncertainty is estimated around
the emissions projections themselves due to, in particular, the aerosol emissions and abatement options among
different gases. Under a low aerosol scenario emissions must be well below 48Gt with very rapid declines. These
trajectories give a 50% probability of 2°C.
domestic political consensus on how to act and implement the required
policies and investments to achieve rapid reductions.
• Annual rate of decline – the faster the rate of reductions, the greater the
overall costs, as it requires a more rapid deployment of new low-carbon
technologies, early retirement of existing assets and a larger impact on
energy prices.
• How low emissions go beyond 2050 – achieving very low levels beyond
2050 relies more heavily on technologies to decarbonise to very low levels
in all sectors, which may not be feasible and is potentially much more
expensive.
Implications for 2020 emissions
Feasible trajectories for keeping a reasonable chance of temperature
increases below 2°C requires emissions to be between 40-48Gt in 2020. As
set out in their research this findings is consistent with the analysis that
underpinned the IPCC conclusions. A later and higher peak in global annual
emissions will mean fewer options subsequently and relying on the rapid
emergence of technologies to drive very rapid emission reductions over the
longer term, with more ‘stranded assets’. This is a higher risk and higher cost
strategy as lower-cost near-term options are missed and greater reductions
are required in the longer term. 44Gt in 2020 requires global annual
reductions of around 3.3% each year after 2020 and annual emissions of
around 16Gt in 2050, which is plausible but still ambitious. The 44GtCO2e in
2020 path demonstrates the most appropriate balance of risks and
opportunities. It encapsulates the economic benefits of early action, while
leaving time between now and 2020 for policies to take effect.
There is some flexibility in the date by which emissions must peak, but a later
peak must be compensated for by more rapid reductions thereafter. With
levels above 48GtCO2e in 2020, we estimate that the world would need to
reduce annual emissions at an average rate of more than 4% per year
between 2020 and 2050, to below 14 GtCO2e in 2050, which would be
considerably more expensive than earlier action.
Evidence shows that delays in participation in a global climate change policy
regime are likely to increase the costs of hitting the target significantly, without
benefiting the late adopters, and may make the target unattainable. Limiting
the rise in global temperatures to a 2°C ceiling above pre-industrial levels is
demanding. But, with well-designed policies applied consistently across
countries, industries and greenhouse gases, modelling exercises suggest it
can be reached and need not cost more than a few percentage points of GDP,
against a backdrop of continued strong economic growth. We should not see
the route to the low-carbon economy merely or mostly in terms of cost and
burden-sharing. These are innovations, investments and opportunities: green
technologies could create the most dynamic and innovative period in
economic history with many benefits (e.g. energy security, safety, biodiversity)
beyond the fundamental one of managing climate change