Report on marginal external damage costs inventory of greenhouse

SIXTH FRAMEWORK PROGRAMME

Project no: 502687

NEEDS

New Energy Externalities Developments for Sustainability

INTEGRATED PROJECT Priority 6.1: Sustainable Energy Systems and, more specifically,

Sub-priority 6.1.3.2.5: Socio-economic tools and concepts for energy strategy.

Delivery n° 5.4 - RS 1b

“Report on marginal external damage costs

inventory of greenhouse gas emissions

Due date of technical paper: Feb 2007

Actual submission date: September 2007

Start date of project: 1 September 2004 Duration: 48 months

Organisation name for this technical paper: David Anthoff

Authors: David Anthoff

Project co-funded by the European Commission within the Sixth Framework Programme (2004-2008) Dissemination Level

PU Public X

PP Restricted to other programme participants (including the Commission Services)

RE Restricted to a group specified by the consortium (including the Commission Services)

CO Confidential, only for members of the consortium (including the Commission Services)

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Report on marginal external damage costs of greenhouse gas emissions New Results from FUND 3.0

Version 1.1

26 September 2007

David Anthoff

Revision history Version Date Change

0.9 9 September 2007 Initial report 1.0 24 September 2007 Small layout edits 1.1 26 September 2007 Added discussion of unknown damage categories (p. 4-5)

Added tables with discount rates (p. 9-10)

Introduction

Marginal damage cost of greenhouse gas emission estimates are widely used today to inform

decision making on climate change mitigation and adaptation. The marginal damage cost of carbon is

commonly referred to as the Social Cost of Carbon (SCC). Marginal damage figures are not the only

measure used to quantify impacts from climate change, other studies have also presented total

damage costs (e.g. Nordhaus and Boyer 2000; Tol 2002; Tol 2002) and more recently new measures

like changes in the balanced growth equivalent (Stern 2006) have been used. Nevertheless, marginal

damage estimates of carbon emissions seem to be most numerous in the literature, and today meta-

studies of marginal damage estimates give a comprehensive overview of these studies (Tol 2005; Tol

2007).

Estimates of the social cost of carbon differ not only because the underlying integrated assessment

models represent key climate and socio-economic relations differently, but also because there are a

number of assumptions to be made to which these estimates are highly sensitive, which cannot

easily be resolved. Examples include the choice of discount rate, the treatment of uncertainty and

the use of equity weighting. Due to this structure of the problem, one can generate a large range of

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social cost of carbon estimates even from a single model, by just changing a few key assumptions for

different model runs.

This report discusses a set of new model results from the integrated assessment model FUND 3.0 and

in particular outlines the assumptions made in different model runs.

Model

This paper uses version 3.0 of the Climate Framework for Uncertainty, Negotiation and Distribution

(FUND). Version 3.0 of FUND corresponds to version 1.6, described and applied by Tol (1999; 2001;

2002), except for the impact module, which is described by Tol (2002; 2002) and updated by Link and

Tol (2004). A further difference is that the current version of the model distinguishes 16 instead of 9

regions. Readers familiar with FUND can skip this section.

Essentially, FUND consists of a set of exogenous scenarios and endogenous perturbations. The model

distinguishes 16 major regions of the world, viz. the United States of America, Canada, Western

Europe, Japan and South Korea, Australia and New Zealand, Central and Eastern Europe, the former

Soviet Union, the Middle East, Central America, South America, South Asia, Southeast Asia, China,

North Africa, Sub-Saharan Africa, and Small Island States. The model runs from 1950 to 2300 in time

steps of one year. The prime reason for starting in 1950 is to initialize the climate change impact

module. In FUND, the impacts of climate change are assumed to depend on the impact of the

previous year, this way reflecting the process of adjustment to climate change. Because the initial

values to be used for the year 1950 cannot be approximated very well, both physical and monetized

impacts of climate change tend to be misrepresented in the first few decades of the model runs. The

22nd and 23rd centuries are included to account for the fact that climate change does not stop in

2100.

The period of 1950-1990 is used for the calibration of the model, which is based on the IMAGE 100-

year database (Batjes and Goldewijk 1994). The period 1990-2000 is based on observations (World

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Resources Institute 2000). The climate scenarios for the period 2010-2100 are based on the EMF14

Standardized Scenario, which lies somewhere in between IS92a and IS92f (Leggett, Pepper et al.

1992). The 2000-2010 period is interpolated from the immediate past, and the period 2100-2300

extrapolated.

The scenarios are defined by the rates of population growth, economic growth, autonomous energy

efficiency improvements as well as the rate of decarbonisation of the energy use (autonomous

carbon efficiency improvements), and emissions of carbon dioxide from land use change, methane

and nitrous oxide. The scenarios of economic and population growth are perturbed by the impact of

climatic change. Population decreases with increasing climate change related deaths that result from

changes in heat stress, cold stress, malaria, and tropical cyclones. Heat and cold stress are assumed

to have an effect only on the elderly, non-reproductive population. In contrast, the other sources of

mortality also affect the number of births. Heat stress only affects the urban population. The share of

the urban population among the total population is based on the World Resources Databases (World

Resources Institute 2000). It is extrapolated based on the statistical relationship between

urbanization and per-capita income, which are estimated from a cross-section of countries in 1995.

Climate-induced migration between the regions of the world also causes the population sizes to

change. Immigrants are assumed to assimilate immediately and completely with the respective host

population.

The tangible impacts are dead-weight losses to the economy. Consumption and investment are

reduced without changing the savings rate. As a result, climate change reduces long-term economic

growth, although consumption is particularly affected in the short-term. Economic growth is also

reduced by carbon dioxide abatement measures. The energy intensity of the economy and the

carbon intensity of the energy supply autonomously decrease over time.

The endogenous parts of FUND consist of the atmospheric concentrations of carbon dioxide,

methane and nitrous oxide, the global mean temperature, the impact of carbon dioxide emission

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reductions on the economy and on emissions, and the impact of the damages to the economy and

the population caused by climate change. Methane and nitrous oxide are taken up in the

atmosphere, and then geometrically depleted. The atmospheric concentration of carbon dioxide,

measured in parts per million by volume, is represented by the five-box model of Maier-Reimer and

Hasselmann (1987). Its parameters are taken from Hammitt et al. (1992). The model also contains

sulphur emissions (Tol 2006).

The radiative forcing of carbon dioxide, methane, nitrous oxide and sulphur aerosols is determined

based on Shine et al. (Shine, Derwent et al. 1990). The global mean temperature T is governed by a

geometric build-up to its equilibrium (determined by the radiative forcing RF), with a half-life of 50

years. In the base case, the global mean temperature rises in equilibrium by 2.5°C for a doubling of

carbon dioxide equivalents. Regional temperature follows from multiplying the global mean

temperature by a fixed factor, which corresponds to the spatial climate change pattern averaged

over 14 GCMs (Mendelsohn, Morrison et al. 2000). The global mean sea level is also geometric, with

its equilibrium level determined by the temperature and a half-life of 50 years. Both temperature

and sea level are calibrated to correspond to the best guess temperature and sea level for the IS92a

scenario of Kattenberg et al.(1996).

The climate impact module, based on Tol (2002; 2002) includes the following categories: agriculture,

forestry, sea level rise, cardiovascular and respiratory disorders related to cold and heat stress,

malaria, dengue fever, schistosomiasis, diarrhoea, energy consumption, water resources, and

unmanaged ecosystems. There has been some discussion of other damage categories in the

literature (cf. section 3.2.1 in Watkiss, Anthoff et al. 2005), but neither have they been modeled in a

quantitative way, nor can one even strictly say whether they will be damages or benefits. Such

damage categories are not included in FUND, but it would be pure speculation to say that this biases

the damage estimates up or down or whether they would make a large or small difference to the

results. Climate change related damages can be attributed to either the rate of change

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(benchmarked at 0.04°C/yr) or the level of change (benchmarked at 1.0°C). Damages from the rate of

temperature change slowly fade, reflecting adaptation (cf. Tol 2002).

People can die prematurely due to temperature stress or vector-borne diseases, or they can migrate

because of sea level rise. Like all impacts of climate change, these effects are monetized. The value of

a statistical life is set to be 200 times the annual per capita income. The resulting value of a statistical

life lies in the middle of the observed range of values in the literature (cf. Cline 1992). The value of

emigration is set to be 3 times the per capita income (Tol 1995; Tol 1996), the value of immigration is

40 per cent of the per capita income in the host region (Cline 1992). Losses of dryland and wetlands

due to sea level rise are modelled explicitly. The monetary value of a loss of one square kilometre of

dryland was on average $4 million in OECD countries in 1990 (cf. Fankhauser 1994). Dryland value is

assumed to be proportional to GDP per square kilometre. Wetland losses are valued at $2 million per

square kilometre on average in the OECD in 1990 (cf. Fankhauser 1994). The wetland value is

assumed to have logistic relation to per capita income. Coastal protection is based on cost-benefit

analysis, including the value of additional wetland lost due to the construction of dikes and

subsequent coastal squeeze.

Other impact categories, such as agriculture, forestry, energy, water, and ecosystems, are directly

expressed in monetary values without an intermediate layer of impacts measured in their ‘natural’

units (cf. Tol 2002). Impacts of climate change on energy consumption, agriculture, and

cardiovascular and respiratory diseases explicitly recognize that there is a climatic optimum, which is

determined by a variety of factors, including plant physiology and the behavior of farmers. Impacts

are positive or negative depending on whether the actual climate conditions are moving closer to or

away from that optimum climate. Impacts are larger if the initial climate conditions are further away

from the optimum climate. The optimum climate is of importance with regard to the potential

impacts. The actual impacts lag behind the potential impacts, depending on the speed of adaptation.

The impacts of not being fully adapted to new climate conditions are always negative (cf. Tol 2002).

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The impacts of climate change on coastal zones, forestry, unmanaged ecosystems, water resources,

diarrhoea malaria, dengue fever, and schistosomiasis are modelled as simple power functions.

Impacts are either negative or positive, and they do not change sign (cf. Tol 2002).

Vulnerability to climate change changes with population growth, economic growth, and technological

progress. Some systems are expected to become more vulnerable, such as water resources (with

population growth), heat-related disorders (with urbanization), and ecosystems and health (with

higher per capita incomes). Other systems are projected to become less vulnerable, such as energy

consumption (with technological progress), agriculture (with economic growth) and vector- and

water-borne diseases (with improved health care) (cf. Tol 2002).

Dimensions of results

The set of results for this model exercise is fairly large. This section will attempt to categorize the

results along various dimensions, explain the parameter choices made for each dimension and give

recommendations on what values should be considered for policy decisions in what way. It will not

attempted to give a full theoretical foundation for all possible parameter choices, but where

adequate references to the appropriate background literature are given. This section is best thought

of as guideline to the result set, it should enable consumers of the accompanying data sets to pick

the right number for further applications from the set of estimates provided.

Physical dimensions

Different gases

This study not only calculates the social cost of carbon, i.e. the marginal damage from an extra ton of

carbon emission, but in addition includes estimates for three other greenhouse gases as well: The

marginal damage of CH4, N2O and SF6 emissions. The procedure to calculate the four marginal

damage figures for the four gases is exactly the same, in each case the model is run twice and the

second run is perturbed by a small, marginal extra emission of the specific gas, after which the

difference in damages between the runs is produced to come to a marginal damage estimate.

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Recommendation

The proper value to look at depends on what gas is emitted in a project, the corresponding marginal

damage figure for that gas should be used.

Different emission periods

Marginal damage estimates are also calculated for different marginal emission periods, in particular

for various emission periods over the next century. It is well known that an extra ton of greenhouse

gas emission today has a different impact on societies than an extra ton of the same greenhouse gas

emission at a later point in time. The main reason for this is the increase in greenhouse gas

concentrations in the atmosphere due to the baseline socio-economic scenario and the non-linear

response of damages to greenhouse gas concentration changes in the atmosphere.

The marginal damage estimates over time start in the year 2005 for this report and are then

calculated in ten year steps up to the year 2095. Ideally one would want to include damages from the

same time span after the date of the marginal emission for all these estimates. Assuming for example

that one is looking at a 300 year time frame, one would ideally want marginal damage estimates that

include all damages caused by the extra emission that occur in the next 300 years after the marginal

emission, e.g. one would want the marginal damage estimates for the year 2015 to include damages

in the years 2015-2315 and estimates for the year 2045 to include damages in the years 2045-2345.

The results presented in this paper do not follow this theoretical ideal, rather the cut of point is

always the end of the time period the model runs to, i.e. damages are always taken into account up

to the year 2300. This is a pragmatic approach, mainly chosen because the model is not build to run

longer than to the year 2300 and at the same time the wish to not artificially truncate marginal

damage estimates for early periods at an earlier date (i.e. one could have limited the damages

considered for SCC figures to the next 200 years after the marginal emission), in particular given that

significant portions of the damage only occur in later time periods.

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Recommendation

In a cost-benefit analysis one should look at the precise year a particular emission is expected to

happen and use the marginal damage emission for that time period when calculating the damages

caused by the project.

Preference dimensions

Implicitly or explicitly any marginal damage estimate of climate change is based on some ranking of

outcomes, i.e. is based on some preference ordering that a potential decision maker is assumed to

hold. There is no consensus on what the “right” or correct preference order should be, and indeed it

is commonly assumed that this question is one that cannot be answered by simple scientific

investigation. In particular, economics as a discipline can only to some degree help with the choice of

preference ordering a decision maker should hold: It can mainly test a given preference ordering for

consistency with for example opinions hold by the public or consistency with other decisions already

made.

For this reason this report presents a variety of results assuming different preference orders, mainly

along two dimension of choice: Discounting and equity weighting.

Discounting

FUND uses the usual Ramsey style discounting, that is the actually discount rate used for discounting

the marginal damage figures is calculated as a combination of the consumption growth rate, the risk

aversion or more general curvature of the utility function parameter and the pure rate of time

preference (also called the utility discount rate). Following most of the literature, the risk aversion

parameter is always set to 1, so that the final discount factor 𝐷𝐹𝑡 ,𝑟 for time 𝑡 and region 𝑟 is

𝐷𝐹𝑡 ,𝑟 =1

1 + 𝜌 + 𝑔𝑖 ,𝑟𝑡𝑖=0

where 𝑔𝑡 ,𝑟 is the per capita consumption growth rate in region 𝑟 at time 𝑡 and 𝜌 is the pure rate of

time preference. The results presented in this report are calculated for three different choices of

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pure rate of time preference, namely 0%, 1% and 3%. The choice of time preference rate constitutes

a real change in the preference order which implicitly underlies the cost-benefit analysis and from

which the discount factor is derived.

The effective discount rates used even for a specific pure rate of time preference varies over time

and region, since per capita consumption growth rates vary over time and by region. To enable some

comparison with other studies, selected equivalent constant consumption discount rates1 for results

that are discounted back to the year 2005 are presented in the following tables:

Year USA CAN WEU JPK ANZ EEU FSU MDE CAM LAM SAS SEA CHI MAF SSA SIS

2006 1.7% 1.9% 1.9% 2.0% 2.0% 2.8% 2.8% 1.1% 1.6% 1.6% 2.8% 3.4% 3.4% 1.6% 1.6% 1.6%

2050 1.5% 1.6% 1.6% 1.6% 1.6% 3.0% 3.0% 2.3% 2.4% 2.4% 2.5% 2.5% 2.9% 2.4% 2.4% 2.4%

2100 1.3% 1.3% 1.3% 1.3% 1.3% 2.3% 2.3% 2.4% 2.4% 2.4% 2.4% 2.4% 2.8% 2.4% 2.4% 2.4%

2150 1.1% 1.1% 1.1% 1.1% 1.1% 1.8% 1.8% 2.1% 2.1% 2.1% 2.1% 2.1% 2.3% 2.1% 2.1% 2.1%

2200 1.0% 1.0% 1.0% 1.0% 1.0% 1.6% 1.6% 1.8% 1.8% 1.8% 1.8% 1.8% 2.0% 1.8% 1.8% 1.8%

2250 0.9% 0.9% 0.9% 0.9% 0.9% 1.4% 1.4% 1.6% 1.6% 1.6% 1.6% 1.6% 1.8% 1.6% 1.6% 1.6%

Table 1: Equivalent constant discount rates for pure rate of time preference of 0%


2006 2.7% 2.9% 2.9% 3.0% 3.0% 3.8% 3.8% 2.1% 2.6% 2.6% 3.8% 4.4% 4.4% 2.6% 2.6% 2.6%

2050 2.5% 2.6% 2.6% 2.6% 2.6% 4.0% 4.0% 3.3% 3.4% 3.4% 3.5% 3.5% 3.9% 3.4% 3.4% 3.4%

2100 2.3% 2.3% 2.3% 2.3% 2.3% 3.3% 3.3% 3.4% 3.4% 3.4% 3.4% 3.4% 3.8% 3.4% 3.4% 3.4%

2150 2.1% 2.1% 2.1% 2.1% 2.1% 2.8% 2.8% 3.1% 3.1% 3.1% 3.1% 3.1% 3.3% 3.1% 3.1% 3.1%

2200 2.0% 2.0% 2.0% 2.0% 2.0% 2.6% 2.6% 2.8% 2.8% 2.8% 2.8% 2.8% 3.0% 2.8% 2.8% 2.8%

2250 1.9% 1.9% 1.9% 1.9% 1.9% 2.4% 2.4% 2.6% 2.6% 2.6% 2.6% 2.6% 2.8% 2.6% 2.6% 2.6%


1 The equivalent constant consumption discount rate 𝐸𝐷𝑅𝑡 ,𝑟 for the year 𝑡 and region 𝑟 is defined as follows:

1

1+𝐸𝐷𝑅𝑡 ,𝑟 𝑡 =

1

1+𝜌+𝑔𝑖 ,𝑟𝑡𝑖=0

, where 𝜌 is the pure rate of time preference and 𝑔𝑡 ,𝑟 is the average per capita growth

rate in year 𝑡 in region 𝑟.

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2006 4.7% 4.9% 4.9% 5.0% 5.0% 5.8% 5.8% 4.1% 4.6% 4.6% 5.8% 6.4% 6.4% 4.6% 4.6% 4.6%

2050 4.5% 4.6% 4.6% 4.6% 4.6% 6.0% 6.0% 5.3% 5.4% 5.4% 5.5% 5.5% 5.9% 5.4% 5.4% 5.4%

2100 4.3% 4.3% 4.3% 4.3% 4.3% 5.3% 5.3% 5.4% 5.4% 5.4% 5.4% 5.4% 5.8% 5.4% 5.4% 5.4%

2150 4.1% 4.1% 4.1% 4.1% 4.1% 4.8% 4.8% 5.1% 5.1% 5.1% 5.1% 5.1% 5.3% 5.1% 5.1% 5.1%

2200 4.0% 4.0% 4.0% 4.0% 4.0% 4.6% 4.6% 4.8% 4.8% 4.8% 4.8% 4.8% 5.0% 4.8% 4.8% 4.8%

2250 3.9% 3.9% 3.9% 3.9% 3.9% 4.4% 4.4% 4.6% 4.6% 4.6% 4.6% 4.6% 4.8% 4.6% 4.6% 4.6%


In recent years it has also been argued that discount rates should be declining (Weitzman 1998;

Weitzman 2001; Pearce, Groom et al. 2003; Groom, Hepburn et al. 2005), mainly because the future

is uncertain. Such results are present in this report in two ways: For probabilistic runs, i.e. results

from Monte Carlo simulations, this will effectively happen automatically, since the discount rate is

derived from an uncertain consumption growth rate. That is, for probabilistic runs, the stochastic

discount rate will be declining for constant pure rate of time preference choices. For deterministic, so

called “Best Guess” results, this report contains results that are discounted with a declining discount

rate according to the UK Greenbook guidelines for long term discounting (see H.M. Treasury 2003

annex 6 for the detailed discount rate schedule). Note the declining discounting numbers are only

explicitly presented for best guess results, because for probabilistic runs all discounting schemes will

essentially have a declining discount rate. Also note that it is unclear how one would combine equity

weights with a declining discount rate in a deterministic setting, so that no such results are

presented.

Recommendation

If one wants to come up with climate change policies that are consistent with expressed preferences

of consumers and other observed decision of national policy makers, it is essential to use a discount

rate that is somewhere close to observed interest rates. In combination with the parameter chosen

for the curvature of the utility function for FUND, the standard approach would be to use a 3% pure

rate of time preference. In order to account for the fact that uncertain discount rates decline, one

should ideally use probabilistic results, or, if that is not possible, use the declining discount rate

scheme.

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Results with 0% pure rate of time preference might be a helpful reminder what a decision maker who

has no preference for the current generation would do.

Equity weighting

Besides discounting, where the problem is to pick a representation of a preference order that fits a

decision makers intertemporal substitutability of consumption, there is a choice between attitudes

towards inequality within a generation, i.e. towards inequality between people. In an integrated

assessment model like FUND, with coarse geographical resolution, this is represented as an attitude

towards inequality in average per capita income between different regions.

For this report, two different schemes are used. One is commonly referred to as results that are

“equity weighted”, the other as results without equity weights. For results that are equity weighted,

there is a further question of how to present such numbers, in particular the question of

normalization. But the choice of normalization is not a choice between different preference orders, it

simply is a choice between different units of presenting equity weighted results. The question of

normalization will therefore be discussed in more detail in the section on presentation dimensions.

The difference between equity weighted and non equity weighted social cost of carbon estimates is

best demonstrated by looking at the underlying welfare functions for the two schemes. Equity

weighted social cost of carbon figures follow directly from a standard, utilitarian welfare function of a

global, benevolent planner:

𝑊𝑒𝑤 = 𝑈 𝐶𝑡 ,𝑟 𝑃𝑡 ,𝑟 1 + 𝜌 −𝑡

𝑟

𝑇

𝑡=0

where 𝑇 is the end of the time period considered, 𝑈 ⋅ is the utility function, 𝐶𝑡,𝑟 is average per capita

income and 𝑃𝑡 ,𝑟 is population in region 𝑟 at time 𝑡 and 𝜌 is the pure rate of time preference. Note

that there aren’t any weights in this welfare function. If one derives the equation for the social cost

of carbon from this welfare function (see Anthoff, Hepburn et al. 2006 for a detailed derivation), one

gets

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𝑆𝐶𝐶𝑒𝑤 = 𝐶0

𝐶0,𝑟 𝐷𝑡,𝑟

1

1 + 𝜌 + 𝑔𝑖 ,𝑟𝑡𝑖=0

𝑇

𝑡=0𝑟

where 𝐶𝑡 is world average per capita income at time 𝑡 and 𝐷𝑡 ,𝑟 is the consumption loss in region 𝑟 at

time 𝑡 caused by the marginal emission of the greenhouse gas. The term “equity weighted” comes

from the equity weight 𝐶0/𝐶0,𝑟 in the social cost of carbon equation, i.e. the weight is present in the

SCC calculation, not in the welfare function.

The equity weight has an appealing interpretation: It gives damages in low income regions more

weight than damages in high income regions and that corresponds nicely with the notion of marginal

declining utility of consumption: The higher the income level of an agent is, the less welfare loss he

or she has from the same absolute loss of income, i.e. the same absolute loss of income causes a

higher welfare loss for a poor agent than for a rich agent.

While the welfare function underpinning the equity weighted marginal damage figures is ethically

appealing, there is a huge difficulty in using it for public policy: It is quite obvious that no national

decision maker (or for this matter groups of nations like the European Union) is even close to operate

by the assumed preference order from which equity weighted social cost of carbon figures follow.

The most simple thought experiment one can do to understand why is to think what the optimal

income redistribution following from the underlying welfare function would look like. The answer is

clear: A decision maker having a preference order which is represented by the 𝑊𝑒𝑤 welfare function

would engage in massive income redistributions from high income countries to low income

countries, on a scale that is clearly not the case when one looks at actual decision made by bodies

like the European Union. If the European Union had a preference ordering like 𝑊𝑒𝑤 , one would

expect to see huge income transfers from the EU to very poor countries, orders of magnitudes over

and above what happens in development programs.

If one does not want to implicitly assume a welfare function for which the optimal solution would be

to change the income distribution of the world in the most fundamental way, an alternative is to only

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look at efficiency and correct the externality failure which the greenhouse gas caused damage is. In

this case the equation to calculate the marginal cost of greenhouse gas emissions is just the standard

present value of the damages:

𝑆𝐶𝐶 = 𝐷𝑡,𝑟

1

1 + 𝜌 + 𝑔𝑖,𝑟𝑡𝑖=0

𝑇

𝑡=0𝑟

More recently even more schemes for a national decision maker have been presented that

investigate more social welfare functions (Anthoff and Tol 2007), but no such results are presented in

this report.

Recommendation

The use of equity weights is not suggested for a regional decision maker, given that one has to

assume a preference order for that decision maker that seems not to be present. As with a low pure

rate of time preference, they might serve as a helpful reminder of what a truly benevolent global

decision maker would do.

Presentation dimensions

Results in this report are presented for different discounting base years and for different equity

weighting normalizations. The various options along these dimensions are best thought of as choices

of presentation, not as a choice between preference orderings. While the numerical figures for

marginal damage estimates that are discounted to different base years might differ widely, they

really represent the same underlying result, i.e. if they are used properly in follow up analysis, it

doesn’t matter to which base year a figure is discounted. This of course implies that in follow up

studies there are certain rules to be followed depending on the choice presentation one has made

for the marginal damage estimate. In this section the choices for discounting base year and equity

weighting normalization are investigated and explained.

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Discounting base year

Marginal damage estimates of greenhouse gas emissions differ depending on the timing of the

marginal emission. Therefore, this report presents marginal damage estimates for different emission

years, i.e. marginal damage estimates over time. For marginal damage estimates in the present, it is

natural to discount them to the present, but once one looks at marginal emissions at a later time, the

question arises as to what base year one should pick for the discounting. Two choices emerge: One

can either discount everything back to the present, or one can discount back to the year of emission.

Assuming that 𝑡 = 0 is the present and that one is looking at the marginal damage from an emission

at a later time 𝑡∗ > 0, the marginal damage estimate without equity weighting, discounted to the

present is given by

𝑆𝐶𝐶0 = 𝐷𝑡 ,𝑟

1

1 + 𝜌 + 𝑔𝑖 ,𝑟𝑡𝑖=0𝑟

𝑇

𝑡=𝑡∗

while the marginal damage estimate discounted to the year of the emission is given by

𝑆𝐶𝐶𝑡∗ = 𝐷𝑡,𝑟

1

1 + 𝜌 + 𝑔𝑖,𝑟𝑡𝑖=𝑡∗𝑟

𝑇

𝑡=𝑡∗

where the only difference between the two equations is what discount rates are included in the

discount factor (note that 𝑆𝐶𝐶0 includes all discount rates from time 0 on, while 𝑆𝐶𝐶𝑡∗ only includes

the discount rates starting from time 𝑡∗).

One normally thinks of discounting as the procedure to convert cost or benefits in the future into

their net present value (NPV). What one is really doing when one is calculating marginal damage

costs and discounts them to the year of the emission is calculate the net “year of emission” value.

Both values can be useful, it is just important that in a cost benefit analysis one always only combines

values that are discounted to the same time, ideally one should operate with the net present value.

Situations where the figures that are discounted to the year of emission are useful are for example

when they are further processed by another model: that model might take as an input the marginal

15

damage of greenhouse gas emissions in the year 2020, then do some further calculations and

internally will then discount its results back to the present, i.e. 2005. In such a case it would be wrong

to use the net present value as the input into this model. In general, the proper procedure is to make

sure that at some point everything is discounted back to the present, whether that is done in one

step or in two steps, where things are first discounted to the year of emission and then later from the

year of emission to the present does not matter.

Recommendation

Unless results are to be used in further calculations that will then discount back to the year 2005, one

should avoid numbers that are discounted to the year of emission and rather use marginal damage

estimates that are discounted to 2005 in the first place.

Equity weighting normalization

The issue of normalization of equity weighted results is closely related to the calibration of the

welfare function. With the type of utilitarian welfare function used in FUND, the same preference

order can be represented by any positive, linear transformation of the welfare function we have

looked at so far. In particular, the following welfare function will represent the same preference

ordering for all 𝛼 > 0:

𝑊 = 𝛼 𝑈 𝐶𝑡 ,𝑟 𝑃𝑡 ,𝑟 1 + 𝜌 −𝑡

𝑟

𝑇

𝑡=0

As such, for a given preference structure, there is not one “right” welfare function, but rather many,

that equally represent this preference order. From each of these many welfare functions, one can

derive an equation to calculate the marginal damage of greenhouse gas emissions, and equally

equations that ought to be used to weight any cost or benefit in a project appraisal. As long as one

consistently uses only one set of equations in a given cost-benefit analysis, the results of such a

decision problem will be the same, regardless from which linear transformation of the welfare

function on derives these equations. The key message here is to make sure to always use only

16

numbers in one cost-benefit analysis that have been weighted by equations that are derived from

the same linear transformation of the welfare function.

In this report, marginal damage estimates from two different linear transformations of the welfare

function for equity weighted results are presented. The first is labeled as “normalized to world

average per capita income”. Here 𝛼 is picked such that the equation for the marginal damage (for an

emission in the present) is

𝑆𝐶𝐶𝑒𝑤 ,𝑤𝑜𝑟𝑙𝑑 𝑎𝑣𝑒𝑟𝑎𝑔𝑒 = 𝐶0

𝐶0,𝑟 𝐷𝑡 ,𝑟

1

1 + 𝜌 + 𝑔𝑖 ,𝑟𝑡𝑖=0

𝑇

𝑡=0𝑟

that is, damages are first discounted by the standard Ramsey discounting rule within every region,

then weighted with a weight that gives more (less) weight to damages in regions that have an

average per capita income below (above) the world average. Of course, if this number is to be used

in a cost-benefit analysis, any other cost or benefit must be weighted by this regional weight as well,

in particular if e.g. a region like the European Union was to use that number in a cost-benefit

analysis, it would have to weigh any other number, like for example abatement costs, with the

appropriate regional equity weight. The European Union has an average per capita consumption well

above world average, so that it would have to weight any abatement or other cost with a weight

below unity. If this is done consistently, there is no problem, but in practice this seems hardly

feasible, in particular when numbers like the marginal damage estimates are handed over to

different research groups and this caveat on how they can be used might get lost.

To circumvent this problem, it has been suggested to instead us marginal damage estimates that are

derived from a different transformation of the welfare function (Anthoff, Hepburn et al. 2006) and

such numbers are also reported here. They are labeled as “normalized to west Europe”, and the

equation to calculate such SCC figures is

17

𝑆𝐶𝐶𝑒𝑤 ,𝑤𝑒𝑠𝑡 𝐸𝑢𝑟𝑜𝑝𝑒 = 𝐶0,𝑊𝐸𝑈

𝐶0,𝑟 𝐷𝑡,𝑟

1

1 + 𝜌 + 𝑔𝑖 ,𝑟𝑡𝑖=0

𝑇

𝑡=0𝑟

where 𝐶0,𝑊𝐸𝑈 is average per capita consumption in west Europe in the present. With this

normalization the regional weight for the European Union obviously is unity and therefore just drops

out. This greatly simplifies things: In a cost-benefit analysis, any cost or benefit within the European

Union can just be discounted by the normal standards and be used directly, without applying further

equity weights to it.

Recommendation

If equity weighted numbers are used, one should use those that are normalized to the region in

which the decision is taking place, since this will greatly reduce the complexities of comparing it with

other numbers.

Uncertainty

The uncertainties surrounding estimates of marginal greenhouse gas damages are huge. These

uncertainties stem from a variety of sources, including uncertainty about scenarios of socio-

economic development, non-perfect knowledge of the physical processes occurring in the

atmosphere, difficulties in assessing the magnitudes of impacts, impacts that are not included in

models like FUND and many more (see Downing, Anthoff et al. 2005 for a systematic treatment of

these uncertainties). One dimension of uncertainties is dealt with explicitly in this report, and that is

uncertainties about precise parameter values. FUND can be run in a deterministic mode, in which

case the model is run exactly once and the best guess value for all input parameters is used. The

result obtained from such a run is also called the best guess result. But for many of these input

parameters the best guess is not the whole story: In many cases the true value for the parameter is

unknown. To investigate these uncertainties, FUND can be run in a probabilistic mode, where a

Monte Carlo simulation is performed. In that case the model is run for 1000 times, and for each run

the input parameters are sampled from probability distributions for each parameter. These

distributions are sometimes taken from the scientific literature, when such information is provided

18

by the underlying studies, sometimes they are expert judgments of the model builder. In any case, it

is assumed that such probabilistic runs are more appropriate for issues as uncertain as climate

change.

The standard way to then aggregate the results of these 1000 runs back into one number would be

to take the arithmetic mean, i.e. calculate the expected value. Such numbers are presented in this

report, but a practical problem shows in this case: With only a 1000 runs there is a fair chance of

extreme outliers being part of the sample, i.e. of runs where values for the input parameters are

extremely large or small, and whose likelihood according to the distribution for the parameter is

much smaller than 1/1000. This is a general problem of Monte Carlo simulations with a limited

number of runs. Such outliers will improperly alter the arithmetic mean of the simulation. The proper

solution to this would be to drastically increase the number of runs and thereby reducing the chance

of such outliers significantly, but due to computational constraints this is not feasible with today’s

hardware with a model like FUND. An alternative is to calculate the mean of a trimmed set of

numbers, i.e. calculate the mean not of the result of the 1000 runs, but rather take out e.g. the 5% of

values of that set at each extreme side (i.e. the highest and lowest 2.5%) and then calculate the mean

of the remaining results. This will solve the problem of outliers, but introduces problems by itself, in

particular if one assumes that the nature of the climate change decision problem is such that the

very tails of such probability distributions of results dominate the rational decision (Weitzman 2007).

If this is indeed the case, truncating the samples also implies that one truncates the most important

runs and is actually getting further away from the appropriate result. At this point, the question

whether the tails of the distribution dominate the decision problem, as Weitzman (2007) argues, is

an open research question, but if he is right, all of the current state of the art integrated assessment

models, including FUND, are at this point not sampling into these tails and would therefore not

reflect this line of thinking. Given that it is unclear at this point what the appropriate measure is, this

report presents trimmed and untrimmed results as well as another indicator, namely the median of

the distribution of results.

19

Recommendation

In general, results from probabilistic runs capture more aspects of the decision problem and

therefore are to be used instead of best guess results whenever possible. On the other hand it is

difficult to give advice as to what precise aggregator of the probability distribution one should use,

given the current research activity surrounding this area.

Bibliography

Anthoff, D., C. Hepburn, et al. (2006). "Equity weighting and the marginal damage costs of climate

change." FNU working papers, from http://www.fnu.zmaw.de/fileadmin/fnu-

files/publication/working-papers/AnthoffHepburnTol2006EquityWeighting.pdf.

Anthoff, D. and R. S. J. Tol (2007). On International Equity Weights and National Decision Making on

Climate Change. FNU Working Paper. Hamburg, Germany, University of Hamburg.

Batjes, J. J. and C. G. M. Goldewijk (1994). The IMAGE 2 Hundred Year (1890-1990) Database of the

Global Environment (HYDE), RIVM, Bilthoven, 410100082.

Cline, W. R. (1992). The Economics of Global Warming. Washington, DC, Institute for International

Economics.

Downing, T., D. Anthoff, et al. (2005). Social Cost of Carbon: A Closer Look at Uncertainty.

Fankhauser, S. (1994). "Protection vs. Retreat -- The Economic Costs of Sea Level Rise." Environment

and Planning A 27: 299-319.

Groom, B., C. Hepburn, et al. (2005). "Discounting the future: the long and the short of it."

Environmental and Resource Economics 31(1).

H.M. Treasury (2003). Annex 6: Discount Rate. Green Book, Appraisal and Evaluation in Central

Government.

Hammitt, J. K., R. J. Lempert, et al. (1992). "A Sequential-Decision Strategy for Abating Climate

Change." Nature 357: 315-318.

http://www.fnu.zmaw.de/fileadmin/fnu-files/publication/working-papers/AnthoffHepburnTol2006EquityWeighting.pdf

http://www.fnu.zmaw.de/fileadmin/fnu-files/publication/working-papers/AnthoffHepburnTol2006EquityWeighting.pdf

20

Kattenberg, A., F. Giorgi, et al. (1996). Climate Models - Projections of Future Climate. Climate

Change 1995: The Science of Climate Change -- Contribution of Working Group I to the

Second Assessment Report of the Intergovernmental Panel on Climate Change. J. T.

Houghton, G. J. Jenkins and J. J. Ephraums. Cambridge Cambridge University Press: 285-357.

Leggett, J., W. J. Pepper, et al. (1992). Emissions scenarios for the IPCC: an update. Climate Change

1992 - The Supplementary Report to the IPCC Scientific Assessment. J. T. Houghton, B. A.

Callander and S. K. Varney. Cambridge, Cambridge University Press: 71-95.

Link, P. M. and R. S. J. Tol (2004). "Possible Economic Impacts of a Shutdown of the Thermohaline

Circulation: an Application of FUND." Portuguese Economic Journal 3(2): 99-114.

Maier-Reimer, E. and K. Hasselmann (1987). "Transport and Storage of Carbon Dioxide in the Ocean:

An Inorganic Ocean Circulation Carbon Cycle Model." Climate Dynamics 2: 63-90.

Mendelsohn, R., W. Morrison, et al. (2000). "Country-specific market impacts of climate change."

Climatic Change 45: 553-569.

Nordhaus, W. and J. Boyer (2000). Warming the World: Economics Models of Global Warming.

Pearce, D. W., B. Groom, et al. (2003). "Valuing the Future - Recent advances in social discounting."

World Economics 4(2): 121-141.

Shine, K. P., R. G. Derwent, et al. (1990). Radiative Forcing of Climate. Change - The IPCC Scientific

Assessment, 1 edn, vol. 1. J. T. Houghton, G. J. Jenkins and J. J. Ephraums. Cambridge

Cambridge University Press: 41-68.

Stern, N. (2006). The Economics of Climate Change. The Stern Review. Cambridge, UK, Cambridge

University Press.

Tol, R. S. J. (1995). "The Damage Costs of Climate Change -- Towards More Comprehensive

Calculations." Environmental and Resource Economics 5: 353-374.

Tol, R. S. J. (1996). "The Damage Costs of Climate Change: Towards a Dynamic Representation."

Ecological Economics 19: 67-90.

21

Tol, R. S. J. (1999). "The Marginal Costs of Greenhouse Gas Emissions." The Energy Journal 20(1): 61-

81.

Tol, R. S. J. (2001). "Equitable cost-benefit analysis of climate change policies." Ecological Economics

36: 71-85.

Tol, R. S. J. (2002). "Estimates of the damage costs of climate change, Part II. Dynamic estimates."

Environmental and Resource Economics 21(2): 135-160.

Tol, R. S. J. (2002). "Estimates of the damage costs of climate change. Part 1: Benchmark estimates."

Environmental and Resource Economics 21(2): 47-73.

Tol, R. S. J. (2002). "Welfare specifications and optimal control of climate change: an application of

fund." Energy Economics 24: 367-76.

Tol, R. S. J. (2005). "The marginal damage costs of carbon dioxide emissions: an assessment of the

uncertainties." Energy Policy 33: 2064–2074.

Tol, R. S. J. (2006). "Multi-Gas Emission Reduction for Climate Change Policy: An Application of

FUND." Energy Journal Multi-Greenhouse Gas Mitigation and Climate Policy Special Issue:

235-250.

Tol, R. S. J. (2007) "The Social Cost of Carbon: Trends, Outliers and Catastrophes." FNU Working

Papers Volume, DOI:

Watkiss, P., D. Anthoff, et al. (2005). The Social Costs of Carbon Review – Methodological Approaches

for Using SCC Estimates in Policy Assessment. London, United Kingdom, Defra.

Weitzman, M. L. (1998). "Why the Far-Distant Future Should Be Discounted at Its Lowest Possible

Rate." Journal of Environmental Economics and Management 36: 201]208.

Weitzman, M. L. (2001). "Gamma Discounting." The American Economic Review 91(1): 260-271.

Weitzman, M. L. (2007). Structural Uncertainty and the Value of Statistical Life in the Economics of

Catastrophic Climate Change.

World Resources Institute (2000). World Resources Database 2000-2001. Washington D.C, World

Resources Institute.

22

23

Results

The model FUND internally uses $ 1995 as its units. Results for this report have been inflation

adjusted to use $ 2005 by using the US consumer price index.

Results that are not equity weighted are labeled “NoEW”, results that are equity weighted and

normalized with average world per capita income are labeled with “AvEW” and those that are

weighted and normalized to the EU are labeled with “WeuEW”.

24

Carbon

Best Guess

Gas C

Best Guess Year of emission

2005 2015 2025 2035 2045 2055 2065 2075 2085 2095

Discounted to 2005

0% pure rate of time preference

NoEW $82.4 $80.7 $78.2 $75.0 $71.3 $67.2 $62.8 $58.4 $54.1 $50.0

AvEW $208.5 $199.7 $190.2 $180.1 $169.5 $158.5 $147.4 $136.5 $126.0 $116.1

WeuEW $993.0 $950.9 $906.0 $857.9 $807.2 $755.0 $702.2 $650.2 $600.1 $552.9


NoEW $10.8 $12.0 $12.5 $12.3 $11.7 $10.9 $9.9 $8.8 $7.8 $6.8

AvEW $38.8 $37.3 $35.3 $32.8 $30.0 $27.0 $24.0 $21.1 $18.5 $16.0

WeuEW $184.7 $177.5 $168.1 $156.3 $143.0 $128.8 $114.4 $100.7 $87.9 $76.3


NoEW -$6.9 -$3.7 -$1.8 -$0.7 -$0.2 $0.1 $0.2 $0.2 $0.2 $0.2

AvEW -$7.1 -$3.4 -$1.1 $0.1 $0.7 $0.9 $0.8 $0.7 $0.6 $0.5

WeuEW -$34.0 -$16.3 -$5.4 $0.5 $3.2 $4.1 $4.0 $3.5 $2.9 $2.3

Declining discount rate

$19.3 $20.3 $20.4 $19.7 $18.5 $17.1 $15.4 $13.8 $12.2 $10.7

Discounted to year of emission


NoEW $82.4 $103.9 $129.0 $158.2 $191.2 $228.1 $271.2 $322.2 $378.8 $433.0

AvEW $208.5 $231.7 $255.5 $279.7 $302.9 $326.0 $351.3 $380.4 $413.9 $446.1

WeuEW $993.0 $1,144.2 $1,291.4 $1,421.4 $1,526.9 $1,603.6 $1,668.7 $1,726.6 $1,769.9 $1,788.8


NoEW $10.8 $17.2 $25.4 $35.5 $47.6 $61.6 $78.4 $98.7 $122.0 $145.9

AvEW $38.8 $47.8 $57.8 $68.7 $79.9 $91.5 $104.0 $118.2 $134.4 $150.8

WeuEW $184.7 $235.9 $292.3 $349.1 $402.7 $449.9 $494.1 $536.6 $574.6 $604.8


NoEW -$6.9 -$6.3 -$5.0 -$3.0 -$0.4 $3.0 $7.1 $12.2 $18.3 $24.7

AvEW -$7.1 -$5.3 -$2.8 $0.4 $3.9 $7.8 $11.9 $16.4 $21.3 $26.4

WeuEW -$34.0 -$26.3 -$13.9 $1.8 $19.8 $38.2 $56.4 $74.3 $91.1 $105.7


$19.3 $24.0 $29.4 $35.3 $41.6 $48.0 $54.3 $60.4 $66.4 $72.4

25

Average

Gas C

Average Year of emission

2005 2015 2025 2035 2045 2055 2065 2075 2085 2095

Discounted to 2005


NoEW $200.5 $203.1 $196.1 $208.5 $767.6 $253.2 $122.3 $116.0 $130.5 $106.4

AvEW $460.5 $441.0 $472.0 $371.6 $2,426.9 $342.5 $269.4 $241.2 $404.0 $210.4

WeuEW $2,192.5 $2,099.3 $2,247.0 $1,769.1 $11,558.7 $1,630.6 $1,282.7 $1,148.2 $1,923.2 $1,001.6


NoEW $45.0 $45.0 $44.4 $42.3 $139.4 $50.4 $21.9 $20.5 $21.3 $16.2

AvEW $122.5 $111.6 $117.0 $86.4 $385.1 $69.8 $51.1 $44.0 $66.7 $33.1

WeuEW $583.1 $531.2 $557.1 $411.1 $1,834.0 $332.3 $243.4 $209.3 $317.4 $157.6


NoEW -$0.5 $1.7 $3.1 $2.7 $10.0 $3.8 $1.2 $1.1 $1.0 $0.7

AvEW $12.3 $11.2 $12.7 $7.8 $17.5 $5.3 $3.3 $2.5 $3.4 $1.4

WeuEW $58.5 $53.3 $60.5 $37.0 $83.4 $25.0 $15.5 $12.1 $16.3 $6.8



NoEW $200.5 $257.6 $319.8 $401.6 $1,621.1 $699.7 $460.7 $569.8 $776.2 $747.0

AvEW $460.5 $511.9 $634.1 $577.4 $4,337.7 $705.3 $642.8 $673.2 $1,328.7 $809.4

WeuEW $2,192.5 $2,526.0 $3,202.7 $2,931.2 $21,863.8 $3,463.8 $3,048.6 $3,049.1 $5,672.0 $3,240.7


NoEW $45.0 $63.3 $89.2 $111.7 $436.8 $229.8 $152.6 $205.7 $285.4 $283.8

AvEW $122.5 $143.1 $191.9 $180.9 $1,024.9 $236.4 $221.6 $246.3 $486.1 $311.9

WeuEW $583.1 $706.1 $968.9 $918.0 $5,165.2 $1,161.0 $1,050.9 $1,115.2 $2,075.0 $1,248.7


NoEW -$0.5 $3.0 $9.7 $13.3 $66.9 $45.9 $27.5 $45.2 $67.3 $69.4

AvEW $12.3 $17.5 $30.9 $29.4 $102.2 $47.5 $45.9 $56.1 $120.2 $78.6

WeuEW $58.5 $86.1 $155.9 $149.0 $514.4 $233.0 $217.6 $254.1 $512.9 $314.7

26

Average, 1% trimmed

Gas C

Average 1% Year of emission

2005 2015 2025 2035 2045 2055 2065 2075 2085 2095

Discounted to 2005


NoEW $158.5 $172.8 $159.1 $134.7 $117.6 $131.9 $100.0 $93.9 $95.5 $83.8

AvEW $381.5 $389.5 $365.5 $281.5 $246.0 $289.3 $212.3 $195.3 $195.8 $169.6

WeuEW $1,816.3 $1,854.6 $1,740.0 $1,340.3 $1,171.3 $1,377.5 $1,010.8 $930.1 $932.5 $807.2


NoEW $35.0 $37.7 $34.6 $28.2 $23.3 $25.8 $17.9 $16.2 $15.4 $12.7

AvEW $102.4 $97.3 $89.8 $65.0 $53.6 $59.2 $40.3 $34.8 $32.8 $26.8

WeuEW $487.4 $463.1 $427.4 $309.4 $255.3 $281.9 $191.7 $165.5 $156.3 $127.6


NoEW -$2.3 $0.3 $1.4 $1.3 $1.1 $1.6 $0.9 $0.8 $0.7 $0.5

AvEW $8.6 $8.4 $8.5 $5.1 $4.0 $4.3 $2.4 $1.8 $1.6 $1.1

WeuEW $40.9 $40.0 $40.6 $24.3 $18.8 $20.6 $11.5 $8.8 $7.6 $5.4



NoEW $158.5 $219.4 $257.2 $268.3 $290.7 $415.4 $376.2 $452.9 $551.2 $589.6

AvEW $381.5 $452.2 $491.0 $437.5 $440.2 $595.8 $506.4 $545.1 $644.0 $652.5

WeuEW $1,816.3 $2,231.5 $2,480.1 $2,220.8 $2,215.6 $2,926.1 $2,402.3 $2,470.0 $2,750.2 $2,611.8


NoEW $35.0 $53.0 $68.8 $76.5 $87.5 $136.2 $124.5 $158.8 $200.7 $225.1

AvEW $102.4 $124.8 $147.2 $136.1 $142.9 $200.5 $174.5 $194.7 $239.3 $252.5

WeuEW $487.4 $615.6 $743.4 $690.9 $719.0 $984.8 $827.5 $881.9 $1,021.8 $1,010.5


NoEW -$2.3 $0.7 $4.8 $6.8 $10.2 $24.0 $20.1 $31.4 $44.1 $53.5

AvEW $8.6 $13.1 $20.7 $19.2 $23.1 $39.1 $33.8 $40.9 $55.7 $62.6

WeuEW $40.9 $64.6 $104.5 $97.5 $116.1 $192.0 $160.5 $185.0 $237.8 $250.3

27

Average 5% trimmed

Gas C


2005 2015 2025 2035 2045 2055 2065 2075 2085 2095

Discounted to 2005


NoEW $123.0 $135.1 $122.3 $101.1 $94.6 $94.1 $81.8 $75.6 $70.9 $66.7

AvEW $299.6 $304.8 $284.1 $218.6 $203.0 $215.6 $178.3 $159.3 $148.0 $131.7

WeuEW $1,426.4 $1,451.1 $1,352.7 $1,040.6 $966.5 $1,026.4 $848.8 $758.6 $704.5 $627.1


NoEW $24.2 $27.9 $25.3 $19.6 $18.0 $17.7 $14.2 $12.7 $11.3 $9.9

AvEW $78.3 $76.1 $68.5 $47.9 $43.1 $44.1 $33.1 $28.0 $24.7 $20.5

WeuEW $372.9 $362.5 $326.2 $227.9 $205.3 $210.0 $157.6 $133.4 $117.8 $97.5


NoEW -$4.5 -$1.5 $0.0 $0.0 $0.5 $0.8 $0.6 $0.5 $0.5 $0.4

AvEW $3.9 $4.8 $5.2 $2.5 $2.6 $2.9 $1.8 $1.4 $1.1 $0.8

WeuEW $18.7 $22.6 $24.9 $11.9 $12.5 $14.0 $8.5 $6.5 $5.4 $3.8



NoEW $123.0 $171.3 $196.0 $202.2 $233.3 $291.8 $306.9 $357.3 $405.1 $453.1

AvEW $299.6 $353.8 $381.7 $339.6 $363.2 $443.9 $425.2 $444.5 $486.7 $506.8

WeuEW $1,426.4 $1,746.0 $1,927.9 $1,724.3 $1,828.3 $2,180.3 $2,017.2 $2,014.5 $2,077.9 $2,028.9


NoEW $24.2 $39.2 $50.1 $53.6 $67.7 $92.3 $98.7 $122.7 $145.6 $168.4

AvEW $78.3 $97.6 $112.3 $100.3 $114.9 $149.4 $143.5 $156.9 $180.4 $193.0

WeuEW $372.9 $481.9 $567.3 $508.9 $578.1 $733.6 $680.6 $711.1 $770.3 $772.4


NoEW -$4.5 -$2.4 $0.5 $0.9 $5.1 $12.6 $13.3 $21.1 $29.1 $36.1

AvEW $3.9 $7.4 $12.7 $9.5 $15.3 $26.5 $25.0 $30.3 $39.9 $44.5

WeuEW $18.7 $36.6 $64.0 $47.9 $77.0 $130.3 $118.7 $137.0 $170.3 $177.9

28

Average 10% trimmed

Gas C


2005 2015 2025 2035 2045 2055 2065 2075 2085 2095

Discounted to 2005


NoEW $101.9 $114.6 $100.4 $81.3 $80.6 $78.3 $68.8 $65.1 $61.1 $55.2

AvEW $257.5 $266.5 $239.9 $183.1 $174.2 $178.0 $152.7 $136.0 $128.3 $110.3

WeuEW $1,225.9 $1,268.8 $1,142.4 $871.6 $829.4 $847.5 $727.1 $647.4 $611.0 $525.2


NoEW $18.2 $22.4 $19.6 $14.5 $14.7 $14.2 $11.5 $10.6 $9.6 $8.1

AvEW $65.6 $64.6 $56.9 $38.5 $36.2 $35.6 $27.8 $23.4 $21.2 $16.9

WeuEW $312.5 $307.8 $270.7 $183.5 $172.2 $169.6 $132.5 $111.6 $100.8 $80.3


NoEW -$5.7 -$2.4 -$0.9 -$0.7 $0.1 $0.5 $0.3 $0.4 $0.4 $0.3

AvEW $1.2 $2.6 $3.4 $1.1 $1.8 $2.1 $1.3 $1.0 $0.9 $0.6

WeuEW $5.7 $12.3 $16.3 $5.3 $8.5 $10.0 $6.3 $5.0 $4.4 $3.0



NoEW $101.9 $145.5 $161.0 $163.3 $198.5 $240.6 $255.3 $302.3 $343.7 $374.9

AvEW $257.5 $309.3 $322.3 $284.4 $311.6 $366.4 $364.2 $379.3 $422.0 $424.5

WeuEW $1,225.9 $1,526.6 $1,628.3 $1,444.3 $1,568.9 $1,800.4 $1,727.9 $1,719.2 $1,802.0 $1,699.2


NoEW $18.2 $31.5 $38.9 $39.8 $55.1 $73.0 $78.9 $100.6 $121.3 $136.1

AvEW $65.6 $82.9 $93.2 $80.7 $96.3 $120.6 $120.6 $131.3 $154.3 $159.0

WeuEW $312.5 $409.1 $470.8 $409.7 $484.9 $592.5 $572.0 $595.0 $659.0 $636.4


NoEW -$5.7 -$4.1 -$2.0 -$2.9 $1.8 $7.2 $8.1 $14.9 $22.1 $26.4

AvEW $1.2 $4.0 $8.3 $4.3 $10.4 $18.9 $18.5 $23.2 $32.3 $34.1

WeuEW $5.7 $19.8 $41.9 $21.5 $52.4 $92.7 $87.7 $104.8 $137.9 $136.6

29

Median

Gas C

Median Year of emission

2005 2015 2025 2035 2045 2055 2065 2075 2085 2095

Discounted to 2005


NoEW $43.2 $51.6 $47.7 $34.6 $32.0 $35.5 $31.2 $27.4 $29.2 $22.5

AvEW $136.8 $133.2 $126.7 $93.9 $82.6 $87.6 $67.8 $61.3 $63.6 $50.0

WeuEW $651.6 $634.6 $603.6 $447.3 $393.4 $417.2 $322.7 $291.9 $302.9 $238.2


NoEW $1.7 $4.6 $5.7 $2.7 $3.7 $4.3 $4.2 $3.7 $3.9 $2.7

AvEW $27.4 $28.7 $25.4 $15.0 $13.6 $15.0 $11.2 $9.0 $9.3 $6.7

WeuEW $130.6 $136.7 $120.8 $71.5 $64.8 $71.6 $53.2 $42.9 $44.5 $32.0


NoEW -$9.1 -$5.7 -$3.1 -$2.3 -$1.1 -$0.5 -$0.3 -$0.1 $0.0 $0.0

AvEW -$7.3 -$4.0 -$1.4 -$2.0 -$0.9 -$0.1 $0.0 $0.1 $0.2 $0.1

WeuEW -$34.6 -$19.1 -$6.5 -$9.5 -$4.1 -$0.4 -$0.1 $0.4 $1.1 $0.5



NoEW $43.2 $64.9 $76.8 $70.2 $76.6 $111.6 $118.6 $126.0 $150.2 $145.8

AvEW $136.8 $154.6 $170.2 $145.9 $147.6 $180.3 $161.7 $170.9 $209.0 $192.1

WeuEW $651.6 $763.6 $860.3 $741.1 $744.1 $886.0 $766.9 $775.4 $893.3 $770.6


NoEW $1.7 $6.6 $11.5 $7.4 $14.8 $24.1 $27.0 $32.3 $47.5 $43.5

AvEW $27.4 $36.8 $41.5 $31.4 $36.2 $50.8 $48.4 $50.3 $68.1 $63.4

WeuEW $130.6 $181.7 $210.0 $159.6 $182.4 $250.3 $229.8 $228.4 $291.1 $253.7


NoEW -$9.1 -$9.5 -$8.2 -$10.3 -$8.8 -$6.0 -$4.8 -$3.0 $1.2 -$0.5

AvEW -$7.3 -$6.3 -$3.3 -$7.5 -$5.0 -$0.7 -$0.2 $1.9 $8.2 $6.3

WeuEW -$34.6 -$30.9 -$16.8 -$38.3 -$25.4 -$3.5 -$1.2 $8.6 $35.2 $25.4

30

CH4

Best Guess

Gas CH4


2005 2015 2025 2035 2045 2055 2065 2075 2085 2095

Discounted to 2005


NoEW $364 $375 $382 $387 $388 $388 $386 $383 $380 $377

AvEW $894 $899 $899 $898 $893 $885 $874 $862 $850 $837

WeuEW $4,258 $4,281 $4,283 $4,277 $4,255 $4,213 $4,161 $4,106 $4,050 $3,986


NoEW $165 $160 $152 $143 $133 $123 $113 $104 $95 $87

AvEW $422 $392 $362 $334 $306 $279 $254 $230 $209 $189

WeuEW $2,011 $1,867 $1,725 $1,590 $1,458 $1,330 $1,209 $1,097 $995 $900


NoEW $61 $51 $41 $33 $26 $20 $15 $12 $9 $7

AvEW $167 $129 $99 $76 $59 $45 $34 $25 $19 $14

WeuEW $793 $614 $473 $364 $279 $212 $160 $121 $91 $69


$185 $182 $177 $171 $163 $155 $146 $137 $127 $117



NoEW $364 $480 $622 $799 $1,013 $1,271 $1,596 $2,011 $2,518 $3,069

AvEW $894 $1,043 $1,208 $1,394 $1,597 $1,820 $2,082 $2,403 $2,793 $3,216

WeuEW $4,258 $5,152 $6,105 $7,086 $8,048 $8,950 $9,888 $10,904 $11,943 $12,894


NoEW $165 $225 $300 $395 $512 $655 $837 $1,073 $1,365 $1,690

AvEW $422 $503 $593 $698 $815 $945 $1,099 $1,288 $1,521 $1,777

WeuEW $2,011 $2,482 $3,000 $3,550 $4,106 $4,647 $5,219 $5,846 $6,502 $7,127


NoEW $61 $86 $119 $160 $212 $276 $357 $464 $598 $750

AvEW $167 $201 $241 $288 $341 $402 $473 $561 $670 $793

WeuEW $793 $993 $1,219 $1,465 $1,721 $1,975 $2,247 $2,547 $2,866 $3,178


$185 $240 $306 $386 $480 $590 $715 $855 $1,008 $1,170

31

Average

Gas CH4


2005 2015 2025 2035 2045 2055 2065 2075 2085 2095

Discounted to 2005


NoEW $1,502 $893 $811 $984 $882 $1,434 $931 $750 $912 $746

AvEW $2,274 $2,083 $1,806 $2,773 $2,002 $2,166 $1,937 $1,603 $1,947 $1,596

WeuEW $10,829 $9,919 $8,598 $13,204 $9,533 $10,311 $9,222 $7,634 $9,268 $7,600


NoEW $706 $403 $338 $369 $310 $493 $284 $211 $238 $177

AvEW $1,121 $958 $780 $984 $704 $729 $592 $454 $508 $377

WeuEW $5,335 $4,559 $3,712 $4,686 $3,351 $3,472 $2,816 $2,162 $2,416 $1,795


NoEW $261 $138 $98 $86 $60 $84 $40 $25 $24 $14

AvEW $459 $331 $229 $211 $135 $122 $81 $53 $49 $30

WeuEW $2,186 $1,576 $1,089 $1,006 $642 $580 $388 $251 $234 $143



NoEW $1,502 $1,142 $1,303 $2,025 $2,291 $4,016 $3,669 $3,630 $6,017 $5,396

AvEW $2,274 $2,419 $2,426 $4,309 $3,582 $4,459 $4,621 $4,474 $6,409 $6,143

WeuEW $10,829 $11,935 $12,255 $21,878 $18,033 $21,903 $21,915 $20,274 $27,334 $24,591


NoEW $706 $570 $664 $1,023 $1,192 $2,248 $2,029 $2,053 $3,480 $3,141

AvEW $1,121 $1,228 $1,278 $2,061 $1,875 $2,470 $2,564 $2,543 $3,704 $3,552

WeuEW $5,335 $6,059 $6,456 $10,464 $9,438 $12,130 $12,160 $11,524 $15,796 $14,219


NoEW $261 $237 $283 $424 $499 $1,008 $905 $940 $1,623 $1,476

AvEW $459 $517 $555 $797 $787 $1,101 $1,144 $1,165 $1,722 $1,654

WeuEW $2,186 $2,549 $2,804 $4,045 $3,960 $5,405 $5,426 $5,278 $7,342 $6,618

32

Average, 1% trimmed

Gas CH4


2005 2015 2025 2035 2045 2055 2065 2075 2085 2095

Discounted to 2005


NoEW $855 $779 $761 $834 $726 $793 $788 $669 $713 $649

AvEW $2,023 $1,817 $1,730 $1,885 $1,631 $1,754 $1,669 $1,414 $1,503 $1,409

WeuEW $9,631 $8,649 $8,236 $8,977 $7,764 $8,352 $7,948 $6,730 $7,156 $6,709


NoEW $418 $359 $321 $319 $261 $264 $239 $188 $183 $155

AvEW $1,010 $860 $751 $730 $590 $587 $509 $401 $389 $335

WeuEW $4,809 $4,093 $3,575 $3,476 $2,808 $2,795 $2,423 $1,909 $1,853 $1,593


NoEW $171 $126 $93 $76 $53 $45 $33 $22 $18 $13

AvEW $421 $305 $221 $173 $118 $98 $70 $47 $37 $27

WeuEW $2,004 $1,452 $1,051 $825 $560 $469 $335 $222 $179 $128



NoEW $855 $994 $1,228 $1,707 $1,863 $2,502 $3,050 $3,176 $4,350 $4,767

AvEW $2,023 $2,109 $2,324 $2,929 $2,917 $3,612 $3,982 $3,944 $4,944 $5,421

WeuEW $9,631 $10,407 $11,739 $14,874 $14,685 $17,742 $18,888 $17,872 $21,105 $21,706


NoEW $418 $506 $633 $879 $993 $1,366 $1,682 $1,797 $2,486 $2,773

AvEW $1,010 $1,102 $1,231 $1,529 $1,570 $1,988 $2,205 $2,245 $2,838 $3,153

WeuEW $4,809 $5,440 $6,218 $7,763 $7,907 $9,765 $10,462 $10,174 $12,115 $12,624


NoEW $171 $215 $271 $374 $432 $609 $753 $826 $1,148 $1,302

AvEW $421 $476 $536 $653 $686 $888 $988 $1,031 $1,313 $1,479

WeuEW $2,004 $2,349 $2,705 $3,317 $3,455 $4,364 $4,686 $4,673 $5,603 $5,920

33

Average 5% trimmed

Gas CH4


2005 2015 2025 2035 2045 2055 2065 2075 2085 2095

Discounted to 2005


NoEW $724 $674 $665 $659 $616 $633 $625 $548 $592 $552

AvEW $1,749 $1,573 $1,542 $1,501 $1,392 $1,431 $1,373 $1,176 $1,278 $1,188

WeuEW $8,328 $7,491 $7,340 $7,148 $6,628 $6,811 $6,538 $5,598 $6,086 $5,657


NoEW $359 $315 $287 $259 $226 $213 $190 $155 $154 $132

AvEW $897 $757 $677 $600 $513 $484 $421 $334 $331 $286

WeuEW $4,273 $3,605 $3,225 $2,856 $2,440 $2,303 $2,005 $1,589 $1,577 $1,360


NoEW $150 $112 $85 $64 $47 $37 $27 $18 $15 $11

AvEW $383 $273 $202 $147 $104 $82 $59 $39 $32 $23

WeuEW $1,821 $1,302 $963 $701 $496 $390 $279 $185 $152 $110



NoEW $724 $860 $1,073 $1,337 $1,569 $1,979 $2,444 $2,622 $3,559 $4,060

AvEW $1,749 $1,826 $2,071 $2,332 $2,490 $2,945 $3,275 $3,280 $4,203 $4,571

WeuEW $8,328 $9,013 $10,461 $11,843 $12,537 $14,469 $15,538 $14,867 $17,951 $18,303


NoEW $359 $444 $565 $707 $856 $1,091 $1,350 $1,488 $2,047 $2,374

AvEW $897 $971 $1,110 $1,256 $1,365 $1,637 $1,825 $1,868 $2,415 $2,691

WeuEW $4,273 $4,791 $5,609 $6,377 $6,873 $8,045 $8,657 $8,467 $10,312 $10,774


NoEW $150 $191 $245 $310 $382 $493 $607 $686 $951 $1,118

AvEW $383 $427 $491 $555 $608 $739 $822 $860 $1,120 $1,271

WeuEW $1,821 $2,105 $2,480 $2,820 $3,061 $3,633 $3,901 $3,897 $4,782 $5,088

34

Average 10% trimmed

Gas CH4


2005 2015 2025 2035 2045 2055 2065 2075 2085 2095

Discounted to 2005


NoEW $649 $602 $605 $590 $551 $558 $555 $479 $520 $487

AvEW $1,599 $1,425 $1,418 $1,341 $1,237 $1,265 $1,226 $1,037 $1,141 $1,054

WeuEW $7,612 $6,785 $6,753 $6,383 $5,892 $6,021 $5,835 $4,939 $5,434 $5,016


NoEW $327 $285 $262 $233 $203 $188 $170 $136 $137 $117

AvEW $830 $693 $628 $540 $462 $431 $377 $295 $298 $253

WeuEW $3,954 $3,301 $2,992 $2,573 $2,198 $2,052 $1,797 $1,407 $1,420 $1,202


NoEW $139 $102 $78 $58 $42 $33 $24 $16 $14 $10

AvEW $357 $254 $189 $134 $95 $74 $53 $35 $29 $20

WeuEW $1,702 $1,208 $900 $638 $451 $350 $252 $165 $138 $97



NoEW $649 $768 $974 $1,192 $1,402 $1,723 $2,161 $2,278 $3,102 $3,556

AvEW $1,599 $1,654 $1,905 $2,082 $2,213 $2,603 $2,923 $2,893 $3,753 $4,053

WeuEW $7,612 $8,164 $9,626 $10,576 $11,145 $12,790 $13,868 $13,115 $16,027 $16,230


NoEW $327 $401 $515 $634 $767 $957 $1,200 $1,295 $1,796 $2,080

AvEW $830 $889 $1,030 $1,131 $1,229 $1,459 $1,635 $1,654 $2,173 $2,379

WeuEW $3,954 $4,387 $5,203 $5,746 $6,191 $7,168 $7,759 $7,496 $9,281 $9,526


NoEW $139 $174 $226 $280 $343 $436 $543 $599 $841 $983

AvEW $357 $396 $459 $505 $553 $664 $743 $767 $1,015 $1,126

WeuEW $1,702 $1,954 $2,318 $2,567 $2,783 $3,262 $3,523 $3,475 $4,335 $4,510

35

Median

Gas CH4


2005 2015 2025 2035 2045 2055 2065 2075 2085 2095

Discounted to 2005


NoEW $429 $395 $406 $388 $333 $341 $329 $272 $304 $264

AvEW $1,099 $993 $1,027 $886 $784 $752 $772 $631 $674 $588

WeuEW $5,236 $4,730 $4,893 $4,220 $3,735 $3,580 $3,674 $3,006 $3,210 $2,797


NoEW $227 $194 $182 $161 $124 $116 $103 $80 $80 $63

AvEW $599 $499 $471 $369 $299 $262 $244 $188 $181 $141

WeuEW $2,853 $2,378 $2,244 $1,759 $1,426 $1,247 $1,160 $893 $863 $674


NoEW $102 $71 $56 $41 $26 $21 $15 $10 $8 $5

AvEW $275 $183 $141 $95 $61 $46 $34 $22 $18 $11

WeuEW $1,308 $873 $673 $454 $292 $218 $164 $106 $85 $54



NoEW $429 $508 $656 $776 $821 $1,056 $1,276 $1,309 $1,757 $1,887

AvEW $1,099 $1,153 $1,380 $1,377 $1,402 $1,547 $1,842 $1,759 $2,213 $2,266

WeuEW $5,236 $5,691 $6,973 $6,993 $7,065 $7,605 $8,732 $7,982 $9,467 $9,052


NoEW $227 $271 $362 $427 $460 $579 $698 $760 $1,030 $1,065

AvEW $599 $640 $772 $774 $797 $886 $1,055 $1,050 $1,319 $1,333

WeuEW $2,853 $3,161 $3,902 $3,928 $4,015 $4,356 $5,008 $4,757 $5,644 $5,338


NoEW $102 $121 $163 $199 $215 $269 $331 $361 $494 $508

AvEW $275 $286 $343 $360 $357 $413 $483 $491 $624 $623

WeuEW $1,308 $1,412 $1,734 $1,827 $1,799 $2,030 $2,294 $2,228 $2,667 $2,496

36

N2O

Best Guess

Gas N2O

BestGuess Year of emission

2005 2015 2025 2035 2045 2055 2065 2075 2085 2095

Discounted to 2005


NoEW $27,748 $27,684 $27,467 $27,105 $26,607 $25,985 $25,245 $24,398 $23,451 $22,412

AvEW $63,238 $62,615 $61,741 $60,611 $59,230 $57,608 $55,761 $53,704 $51,459 $49,043

WeuEW $301,184 $298,217 $294,052 $288,672 $282,094 $274,372 $265,571 $255,778 $245,083 $233,578


NoEW $7,984 $7,532 $7,044 $6,537 $6,023 $5,515 $5,020 $4,542 $4,087 $3,655

AvEW $18,567 $17,217 $15,890 $14,590 $13,326 $12,106 $10,940 $9,835 $8,797 $7,827

WeuEW $88,427 $82,001 $75,681 $69,490 $63,466 $57,658 $52,105 $46,843 $41,897 $37,280


NoEW $1,637 $1,338 $1,076 $855 $671 $522 $403 $309 $235 $178

AvEW $4,034 $3,164 $2,470 $1,917 $1,479 $1,133 $863 $653 $492 $369

WeuEW $19,212 $15,069 $11,766 $9,132 $7,042 $5,396 $4,109 $3,111 $2,343 $1,755


$9,898 $9,480 $9,010 $8,499 $7,957 $7,393 $6,818 $6,239 $5,664 $5,105



NoEW $27,748 $35,461 $44,793 $56,136 $69,578 $85,434 $104,740 $128,418 $155,752 $183,273

AvEW $63,238 $72,665 $82,909 $94,104 $105,864 $118,491 $132,855 $149,657 $169,030 $188,454

WeuEW $301,184 $358,829 $419,107 $478,304 $533,597 $582,806 $631,114 $679,230 $722,792 $755,691


NoEW $7,984 $10,623 $13,938 $18,100 $23,205 $29,438 $37,258 $47,135 $58,978 $71,611

AvEW $18,567 $22,071 $26,037 $30,533 $35,461 $40,952 $47,355 $55,002 $64,054 $73,650

WeuEW $88,427 $108,990 $131,619 $155,190 $178,738 $201,425 $224,953 $249,631 $273,903 $295,333


NoEW $1,637 $2,281 $3,118 $4,195 $5,549 $7,245 $9,421 $12,232 $15,700 $19,556

AvEW $4,034 $4,934 $5,991 $7,226 $8,621 $10,217 $12,111 $14,412 $17,192 $20,254

WeuEW $19,212 $24,367 $30,287 $36,728 $43,454 $50,251 $57,533 $65,408 $73,517 $81,216


$9,898 $12,035 $14,513 $17,347 $20,536 $24,062 $27,876 $31,905 $36,070 $40,300

37

Average

Gas N2O


2005 2015 2025 2035 2045 2055 2065 2075 2085 2095

Discounted to 2005


NoEW $57,775 $69,395 $54,626 $62,067 $57,331 $77,796 $57,038 $58,143 $38,207 $53,966

AvEW $122,603 $153,136 $125,094 $124,643 $103,773 $165,541 $96,086 $110,565 $73,507 $116,720

WeuEW $583,743 $729,083 $595,598 $593,443 $494,070 $788,208 $457,487 $526,398 $349,987 $555,670


NoEW $17,394 $19,153 $14,594 $15,097 $13,150 $16,550 $11,579 $11,122 $6,948 $9,116

AvEW $39,082 $42,544 $33,888 $31,380 $25,084 $35,137 $20,482 $21,478 $13,491 $19,603

WeuEW $186,076 $202,548 $161,342 $149,404 $119,425 $167,298 $97,518 $102,256 $64,236 $93,322


NoEW $3,967 $3,560 $2,399 $2,007 $1,504 $1,530 $967 $790 $431 $468

AvEW $9,383 $8,019 $5,579 $4,297 $3,025 $3,240 $1,788 $1,532 $834 $984

WeuEW $44,673 $38,176 $26,560 $20,457 $14,403 $15,428 $8,514 $7,292 $3,970 $4,685



NoEW $57,775 $88,568 $87,648 $124,917 $139,766 $248,511 $203,992 $264,740 $218,605 $433,618

AvEW $122,603 $177,763 $168,059 $193,648 $185,637 $340,780 $229,166 $308,557 $241,752 $449,266

WeuEW $583,743 $877,274 $848,903 $983,298 $934,579 $1,674,315 $1,087,228 $1,397,949 $1,032,221 $1,797,832


NoEW $17,394 $26,987 $28,647 $41,114 $48,149 $86,778 $76,380 $102,731 $88,545 $178,695

AvEW $39,082 $54,555 $55,553 $65,713 $66,812 $118,963 $88,750 $120,291 $98,360 $184,756

WeuEW $186,076 $269,216 $280,596 $333,663 $336,340 $584,460 $421,028 $544,960 $419,960 $739,337


NoEW $3,967 $6,085 $6,957 $9,813 $12,102 $21,227 $20,836 $28,784 $26,128 $52,425

AvEW $9,383 $12,510 $13,537 $16,204 $17,655 $29,246 $25,129 $33,847 $29,182 $54,168

WeuEW $44,673 $61,733 $68,372 $82,273 $88,871 $143,675 $119,203 $153,329 $124,588 $216,762

38

Average, 1% trimmed

Gas N2O


2005 2015 2025 2035 2045 2055 2065 2075 2085 2095

Discounted to 2005


NoEW $52,616 $57,395 $49,945 $52,906 $48,913 $54,037 $46,339 $46,246 $34,336 $38,339

AvEW $113,404 $125,468 $105,087 $106,798 $93,832 $116,328 $86,150 $93,686 $68,083 $79,572

WeuEW $539,941 $597,367 $500,332 $508,477 $446,735 $553,858 $410,174 $446,039 $324,167 $378,867


NoEW $16,219 $16,434 $13,496 $13,112 $11,584 $11,968 $9,651 $8,956 $6,244 $6,471

AvEW $36,771 $36,271 $29,193 $27,446 $23,062 $26,186 $18,471 $18,330 $12,556 $13,521

WeuEW $175,068 $172,694 $138,989 $130,675 $109,799 $124,674 $87,943 $87,266 $59,786 $64,379


NoEW $3,765 $3,141 $2,232 $1,793 $1,384 $1,203 $832 $649 $388 $336

AvEW $8,980 $7,070 $4,970 $3,878 $2,836 $2,608 $1,628 $1,324 $780 $697

WeuEW $42,753 $33,661 $23,662 $18,462 $13,502 $12,415 $7,749 $6,303 $3,714 $3,319



NoEW $52,616 $72,779 $80,318 $106,094 $121,278 $171,276 $171,760 $220,508 $197,208 $280,013

AvEW $113,404 $145,644 $141,183 $165,923 $167,859 $239,505 $205,472 $261,408 $223,888 $306,139

WeuEW $539,941 $718,787 $713,122 $842,515 $845,040 $1,176,512 $974,792 $1,184,535 $956,070 $1,225,808


NoEW $16,219 $23,028 $26,507 $35,477 $43,137 $62,958 $65,648 $86,216 $80,269 $115,861

AvEW $36,771 $46,508 $47,856 $57,469 $61,427 $88,668 $80,037 $102,638 $91,532 $127,385

WeuEW $175,068 $229,536 $241,721 $291,836 $309,231 $435,557 $379,688 $465,067 $390,867 $510,036


NoEW $3,765 $5,352 $6,471 $8,719 $11,247 $16,709 $18,259 $24,473 $23,850 $34,668

AvEW $8,980 $11,029 $12,060 $14,623 $16,551 $23,536 $22,872 $29,250 $27,294 $38,355

WeuEW $42,753 $54,433 $60,912 $74,252 $83,315 $115,611 $108,498 $132,526 $116,548 $153,556

39

Average 5% trimmed

Gas N2O


2005 2015 2025 2035 2045 2055 2065 2075 2085 2095

Discounted to 2005


NoEW $45,586 $46,188 $41,891 $42,170 $39,373 $38,558 $35,587 $38,047 $29,237 $32,242

AvEW $97,191 $97,619 $88,700 $87,144 $80,086 $81,208 $72,391 $75,624 $58,602 $64,807

WeuEW $462,755 $464,796 $422,325 $414,911 $381,301 $386,660 $344,678 $360,053 $279,034 $308,571


NoEW $14,231 $13,473 $11,417 $10,727 $9,571 $8,647 $7,540 $7,426 $5,382 $5,482

AvEW $32,160 $29,905 $24,978 $23,041 $19,836 $18,648 $15,674 $14,968 $10,858 $11,109

WeuEW $153,123 $142,387 $118,928 $109,706 $94,444 $88,787 $74,629 $71,264 $51,700 $52,895


NoEW $3,382 $2,716 $1,935 $1,521 $1,177 $895 $671 $544 $338 $288

AvEW $8,117 $6,261 $4,349 $3,365 $2,471 $1,954 $1,401 $1,101 $680 $579

WeuEW $38,644 $29,812 $20,708 $16,020 $11,767 $9,303 $6,670 $5,240 $3,238 $2,755



NoEW $45,586 $58,557 $67,163 $84,494 $98,108 $118,090 $134,081 $176,579 $166,767 $224,872

AvEW $97,191 $113,312 $119,160 $135,380 $143,257 $167,176 $172,639 $210,985 $192,702 $249,315

WeuEW $462,755 $559,269 $601,940 $687,482 $721,267 $821,347 $819,136 $956,183 $822,955 $998,363


NoEW $14,231 $18,903 $22,359 $29,021 $35,589 $43,838 $51,936 $69,768 $68,198 $94,085

AvEW $32,160 $38,344 $40,946 $48,245 $52,830 $63,137 $67,909 $83,799 $79,148 $104,653

WeuEW $153,123 $189,252 $206,832 $245,006 $265,985 $310,183 $322,205 $379,787 $338,000 $419,055


NoEW $3,382 $4,631 $5,587 $7,382 $9,518 $12,061 $14,920 $20,110 $20,428 $28,575

AvEW $8,117 $9,768 $10,553 $12,687 $14,422 $17,635 $19,685 $24,315 $23,792 $31,833

WeuEW $38,644 $48,209 $53,307 $64,428 $72,607 $86,636 $93,396 $110,192 $101,606 $127,467

40

Average 10% trimmed

Gas N2O


2005 2015 2025 2035 2045 2055 2065 2075 2085 2095

Discounted to 2005


NoEW $40,500 $40,973 $36,578 $37,314 $33,995 $33,475 $31,587 $33,301 $26,206 $28,556

AvEW $87,578 $87,236 $77,450 $77,496 $70,506 $70,360 $64,655 $66,891 $52,504 $57,364

WeuEW $416,995 $415,370 $368,778 $368,987 $335,707 $335,017 $307,843 $318,494 $250,002 $273,138


NoEW $12,861 $12,196 $10,135 $9,584 $8,287 $7,583 $6,791 $6,548 $4,837 $4,875

AvEW $29,111 $27,115 $22,151 $20,645 $17,555 $16,328 $14,146 $13,280 $9,792 $9,870

WeuEW $138,610 $129,104 $105,471 $98,298 $83,585 $77,743 $67,353 $63,233 $46,627 $46,996


NoEW $3,110 $2,496 $1,745 $1,380 $1,030 $795 $611 $483 $305 $256

AvEW $7,462 $5,788 $3,922 $3,052 $2,205 $1,732 $1,280 $978 $618 $517

WeuEW $35,530 $27,558 $18,674 $14,533 $10,499 $8,248 $6,093 $4,657 $2,942 $2,462



NoEW $40,500 $51,962 $58,504 $74,523 $84,264 $101,964 $118,413 $155,202 $148,480 $197,416

AvEW $87,578 $101,257 $104,043 $120,385 $126,103 $144,832 $154,191 $186,585 $172,628 $220,663

WeuEW $416,995 $499,797 $525,618 $611,389 $635,020 $711,644 $731,599 $845,806 $737,331 $883,712


NoEW $12,861 $17,106 $19,797 $25,876 $30,741 $38,277 $46,505 $61,416 $60,789 $82,862

AvEW $29,111 $34,766 $36,309 $43,226 $46,746 $55,276 $61,287 $74,341 $71,374 $92,969

WeuEW $138,610 $171,598 $183,429 $219,530 $235,403 $271,599 $290,793 $336,982 $304,837 $372,316


NoEW $3,110 $4,254 $5,030 $6,669 $8,318 $10,646 $13,495 $17,716 $18,260 $25,235

AvEW $7,462 $9,029 $9,516 $11,509 $12,864 $15,632 $17,979 $21,601 $21,620 $28,441

WeuEW $35,530 $44,563 $48,071 $58,447 $64,782 $76,805 $85,308 $97,919 $92,337 $113,898

41

Median

Gas N2O


2005 2015 2025 2035 2045 2055 2065 2075 2085 2095

Discounted to 2005


NoEW $24,868 $28,113 $21,735 $22,856 $21,436 $20,926 $19,414 $19,812 $16,573 $16,603

AvEW $56,688 $59,946 $49,749 $48,320 $45,219 $43,728 $38,149 $40,414 $34,166 $34,758

WeuEW $269,918 $285,437 $236,873 $230,132 $215,167 $208,230 $181,695 $192,464 $162,710 $165,580


NoEW $8,180 $8,517 $6,106 $6,088 $5,215 $4,790 $4,058 $3,922 $3,064 $2,920

AvEW $19,581 $19,135 $14,642 $13,516 $11,403 $10,381 $8,466 $8,223 $6,458 $6,044

WeuEW $93,240 $91,119 $69,723 $64,373 $54,297 $49,436 $40,317 $39,151 $30,754 $28,790


NoEW $2,158 $1,831 $1,128 $934 $672 $528 $364 $300 $199 $155

AvEW $5,440 $4,291 $2,757 $2,119 $1,448 $1,137 $770 $619 $404 $315

WeuEW $25,912 $20,437 $13,136 $10,093 $6,898 $5,415 $3,667 $2,948 $1,927 $1,503



NoEW $24,868 $35,940 $34,672 $45,096 $52,355 $61,664 $68,647 $87,158 $95,260 $110,818

AvEW $56,688 $69,577 $66,802 $75,040 $80,849 $90,005 $90,917 $112,637 $112,331 $133,665

WeuEW $269,918 $343,454 $337,614 $381,313 $407,005 $442,325 $431,782 $511,075 $479,862 $535,679


NoEW $8,180 $11,899 $11,880 $16,427 $19,108 $23,569 $27,060 $34,381 $38,308 $47,239

AvEW $19,581 $24,532 $23,998 $28,279 $30,351 $35,108 $36,646 $46,034 $47,045 $56,927

WeuEW $93,240 $121,110 $121,256 $143,760 $152,916 $172,700 $174,059 $208,640 $201,045 $228,049


NoEW $2,158 $3,081 $3,236 $4,467 $5,270 $6,672 $7,859 $10,392 $11,564 $14,697

AvEW $5,440 $6,691 $6,686 $7,983 $8,442 $10,255 $10,806 $13,671 $14,118 $17,370

WeuEW $25,912 $33,047 $33,814 $40,592 $42,561 $50,427 $51,340 $61,987 $60,455 $69,540

42

SF6

Best Guess

Gas SF6


2005 2015 2025 2035 2045 2055 2065 2075 2085 2095

Discounted to 2005


NoEW $1,917 $1,857 $1,793 $1,724 $1,650 $1,574 $1,494 $1,411 $1,326 $1,240

AvEW $4,275 $4,127 $3,971 $3,807 $3,635 $3,458 $3,274 $3,087 $2,895 $2,702

WeuEW $20,361 $19,656 $18,911 $18,130 $17,314 $16,468 $15,595 $14,700 $13,789 $12,867


NoEW $419 $390 $361 $332 $303 $275 $249 $223 $199 $177

AvEW $947 $872 $799 $729 $662 $597 $536 $479 $426 $376

WeuEW $4,510 $4,152 $3,806 $3,472 $3,151 $2,845 $2,555 $2,283 $2,028 $1,792


NoEW $63 $51 $42 $33 $26 $20 $16 $12 $9 $7

AvEW $151 $119 $94 $73 $57 $44 $34 $26 $20 $15

WeuEW $719 $568 $447 $350 $272 $210 $161 $123 $93 $70


$545 $513 $480 $446 $412 $379 $345 $313 $281 $251



NoEW $1,917 $2,380 $2,925 $3,572 $4,319 $5,179 $6,203 $7,435 $8,818 $10,149

AvEW $4,275 $4,789 $5,332 $5,910 $6,498 $7,112 $7,801 $8,601 $9,510 $10,381

WeuEW $20,361 $23,650 $26,954 $30,040 $32,751 $34,980 $37,060 $39,037 $40,667 $41,629


NoEW $419 $551 $715 $919 $1,169 $1,471 $1,847 $2,318 $2,878 $3,465

AvEW $947 $1,118 $1,309 $1,525 $1,760 $2,020 $2,322 $2,680 $3,101 $3,540

WeuEW $4,510 $5,519 $6,619 $7,753 $8,873 $9,938 $11,031 $12,164 $13,258 $14,194


NoEW $63 $88 $120 $163 $217 $284 $372 $486 $627 $785

AvEW $151 $186 $228 $277 $333 $397 $474 $568 $682 $808

WeuEW $719 $919 $1,151 $1,407 $1,677 $1,953 $2,252 $2,579 $2,917 $3,242


$545 $639 $747 $868 $1,003 $1,150 $1,308 $1,474 $1,645 $1,818

43

Average

Gas SF6


2005 2015 2025 2035 2045 2055 2065 2075 2085 2095

Discounted to 2005


NoEW $3,764 $18,663 $4,339 $2,948 $3,561 $3,046 $4,025 $2,483 $3,068 $3,135

AvEW $7,611 $53,710 $9,410 $5,825 $7,864 $5,707 $6,765 $4,719 $6,635 $5,289

WeuEW $36,235 $255,533 $44,794 $27,732 $37,442 $27,171 $32,207 $22,470 $31,583 $25,180


NoEW $884 $4,074 $883 $596 $678 $552 $690 $408 $467 $443

AvEW $1,889 $11,485 $1,971 $1,225 $1,505 $1,077 $1,193 $797 $1,008 $766

WeuEW $8,994 $54,644 $9,381 $5,834 $7,165 $5,127 $5,679 $3,795 $4,800 $3,647


NoEW $152 $572 $106 $65 $62 $44 $46 $24 $23 $18

AvEW $346 $1,575 $241 $140 $137 $89 $83 $48 $49 $32

WeuEW $1,648 $7,493 $1,147 $667 $652 $423 $394 $230 $231 $153



NoEW $3,764 $24,594 $6,986 $5,830 $8,988 $9,218 $14,570 $11,458 $18,965 $22,298

AvEW $7,611 $62,379 $12,646 $9,051 $14,068 $11,750 $16,135 $13,166 $21,834 $20,372

WeuEW $36,235 $307,480 $63,846 $45,950 $70,826 $57,717 $76,541 $59,672 $93,151 $81,472


NoEW $884 $5,920 $1,743 $1,599 $2,560 $2,783 $4,575 $3,838 $6,417 $7,775

AvEW $1,889 $14,735 $3,231 $2,566 $4,008 $3,647 $5,169 $4,462 $7,356 $7,224

WeuEW $8,994 $72,631 $16,315 $13,029 $20,178 $17,913 $24,518 $20,222 $31,383 $28,893


NoEW $152 $1,007 $310 $316 $509 $590 $1,000 $902 $1,491 $1,850

AvEW $346 $2,458 $585 $528 $799 $802 $1,163 $1,068 $1,703 $1,766

WeuEW $1,648 $12,118 $2,953 $2,683 $4,021 $3,939 $5,516 $4,841 $7,264 $7,063

44

Average, 1% trimmed

Gas SF6


2005 2015 2025 2035 2045 2055 2065 2075 2085 2095

Discounted to 2005


NoEW $3,455 $3,685 $3,554 $2,571 $3,088 $2,626 $2,643 $2,132 $2,313 $1,946

AvEW $6,999 $7,486 $6,959 $5,259 $6,376 $5,018 $5,280 $4,169 $4,513 $3,653

WeuEW $33,324 $35,640 $33,133 $25,039 $30,359 $23,890 $25,137 $19,849 $21,488 $17,390


NoEW $814 $819 $731 $526 $592 $482 $465 $356 $358 $288

AvEW $1,745 $1,759 $1,528 $1,124 $1,257 $951 $947 $709 $709 $548

WeuEW $8,306 $8,373 $7,275 $5,350 $5,987 $4,528 $4,509 $3,376 $3,373 $2,609


NoEW $142 $120 $90 $59 $55 $39 $33 $22 $18 $13

AvEW $324 $274 $200 $130 $120 $80 $67 $43 $36 $24

WeuEW $1,545 $1,306 $952 $620 $570 $379 $321 $207 $170 $115



NoEW $3,455 $4,672 $5,630 $5,137 $7,667 $7,999 $9,857 $10,011 $13,562 $13,299

AvEW $6,999 $8,690 $9,349 $8,171 $11,405 $10,330 $12,594 $11,629 $14,845 $14,059

WeuEW $33,324 $42,885 $47,224 $41,488 $57,428 $50,747 $59,738 $52,712 $63,374 $56,267


NoEW $814 $1,149 $1,422 $1,423 $2,210 $2,437 $3,178 $3,379 $4,691 $4,863

AvEW $1,745 $2,255 $2,505 $2,353 $3,349 $3,220 $4,104 $3,969 $5,167 $5,165

WeuEW $8,306 $11,129 $12,652 $11,948 $16,861 $15,821 $19,466 $17,991 $22,055 $20,669


NoEW $142 $206 $260 $285 $448 $526 $724 $801 $1,125 $1,242

AvEW $324 $428 $485 $491 $698 $719 $947 $960 $1,252 $1,326

WeuEW $1,545 $2,112 $2,452 $2,494 $3,516 $3,530 $4,493 $4,353 $5,346 $5,308

45

Average 5% trimmed

Gas SF6


2005 2015 2025 2035 2045 2055 2065 2075 2085 2095

Discounted to 2005


NoEW $2,893 $2,975 $2,658 $2,166 $2,420 $2,102 $2,106 $1,806 $1,757 $1,589

AvEW $5,842 $6,270 $5,234 $4,350 $4,900 $4,113 $4,268 $3,556 $3,554 $3,024

WeuEW $27,815 $29,851 $24,922 $20,713 $23,331 $19,582 $20,323 $16,932 $16,922 $14,400


NoEW $693 $685 $578 $450 $470 $393 $378 $302 $277 $236

AvEW $1,490 $1,492 $1,199 $948 $983 $794 $777 $605 $564 $456

WeuEW $7,094 $7,104 $5,709 $4,511 $4,682 $3,783 $3,699 $2,883 $2,686 $2,173


NoEW $124 $104 $76 $51 $45 $33 $27 $18 $14 $10

AvEW $287 $239 $168 $113 $96 $69 $57 $37 $29 $20

WeuEW $1,369 $1,137 $798 $539 $458 $326 $269 $178 $139 $97



NoEW $2,893 $3,777 $4,232 $4,294 $5,947 $6,328 $7,865 $8,350 $10,029 $10,585

AvEW $5,842 $7,278 $7,032 $6,758 $8,764 $8,466 $10,180 $9,918 $11,687 $11,636

WeuEW $27,815 $35,918 $35,522 $34,321 $44,132 $41,596 $48,298 $44,965 $49,908 $46,591


NoEW $693 $961 $1,127 $1,210 $1,733 $1,964 $2,581 $2,829 $3,518 $3,894

AvEW $1,490 $1,913 $1,966 $1,984 $2,619 $2,690 $3,366 $3,389 $4,112 $4,300

WeuEW $7,094 $9,442 $9,929 $10,075 $13,187 $13,215 $15,970 $15,362 $17,558 $17,216


NoEW $124 $178 $220 $248 $363 $440 $603 $678 $869 $1,005

AvEW $287 $373 $407 $427 $562 $619 $794 $824 $1,020 $1,116

WeuEW $1,369 $1,839 $2,055 $2,167 $2,828 $3,039 $3,769 $3,735 $4,355 $4,467

46

Average 10% trimmed

Gas SF6


2005 2015 2025 2035 2045 2055 2065 2075 2085 2095

Discounted to 2005


NoEW $2,570 $2,574 $2,323 $1,914 $2,073 $1,845 $1,825 $1,605 $1,516 $1,379

AvEW $5,194 $5,519 $4,609 $3,867 $4,178 $3,646 $3,706 $3,197 $3,076 $2,673

WeuEW $24,732 $26,280 $21,944 $18,411 $19,894 $17,359 $17,647 $15,225 $14,645 $12,728


NoEW $623 $595 $512 $401 $407 $347 $329 $270 $241 $206

AvEW $1,345 $1,327 $1,069 $848 $848 $704 $678 $544 $493 $405

WeuEW $6,402 $6,319 $5,088 $4,036 $4,040 $3,353 $3,226 $2,592 $2,350 $1,926


NoEW $114 $93 $69 $46 $40 $29 $24 $17 $13 $9

AvEW $265 $215 $153 $102 $85 $61 $50 $34 $26 $18

WeuEW $1,263 $1,024 $727 $488 $404 $290 $237 $160 $123 $86



NoEW $2,570 $3,269 $3,682 $3,779 $5,103 $5,581 $6,797 $7,388 $8,586 $9,188

AvEW $5,194 $6,407 $6,191 $6,006 $7,472 $7,505 $8,839 $8,918 $10,113 $10,284

WeuEW $24,732 $31,621 $31,276 $30,505 $37,632 $36,873 $41,939 $40,432 $43,194 $41,180


NoEW $623 $835 $996 $1,074 $1,496 $1,738 $2,236 $2,508 $3,039 $3,378

AvEW $1,345 $1,702 $1,752 $1,775 $2,259 $2,384 $2,935 $3,047 $3,597 $3,811

WeuEW $6,402 $8,399 $8,848 $9,013 $11,377 $11,715 $13,928 $13,814 $15,362 $15,259


NoEW $114 $159 $199 $223 $317 $389 $525 $606 $758 $874

AvEW $265 $336 $370 $386 $495 $550 $700 $744 $903 $996

WeuEW $1,263 $1,656 $1,870 $1,962 $2,492 $2,703 $3,323 $3,371 $3,857 $3,986

47

Median

Gas SF6


2005 2015 2025 2035 2045 2055 2065 2075 2085 2095

Discounted to 2005


NoEW $1,551 $1,454 $1,500 $1,235 $1,180 $1,150 $1,117 $1,000 $940 $861

AvEW $3,218 $3,142 $3,103 $2,552 $2,435 $2,336 $2,269 $1,970 $1,816 $1,706

WeuEW $15,319 $14,960 $14,772 $12,153 $11,592 $11,118 $10,805 $9,380 $8,648 $8,128


NoEW $391 $360 $339 $260 $235 $221 $202 $170 $154 $128

AvEW $890 $812 $759 $570 $499 $452 $416 $349 $304 $262

WeuEW $4,239 $3,865 $3,619 $2,715 $2,376 $2,149 $1,983 $1,662 $1,447 $1,247


NoEW $76 $60 $49 $31 $25 $19 $15 $11 $8 $6

AvEW $188 $144 $111 $73 $55 $38 $32 $23 $16 $12

WeuEW $897 $684 $530 $346 $260 $182 $152 $110 $77 $57



NoEW $1,551 $1,834 $2,379 $2,426 $2,917 $3,445 $4,096 $4,362 $5,255 $5,593

AvEW $3,218 $3,648 $4,169 $3,961 $4,358 $4,814 $5,415 $5,489 $5,963 $6,553

WeuEW $15,319 $18,001 $21,056 $20,137 $21,927 $23,620 $25,678 $24,910 $25,505 $26,295


NoEW $391 $500 $660 $695 $881 $1,072 $1,389 $1,559 $1,909 $2,084

AvEW $890 $1,041 $1,244 $1,194 $1,331 $1,530 $1,800 $1,955 $2,217 $2,468

WeuEW $4,239 $5,137 $6,293 $6,064 $6,693 $7,509 $8,559 $8,856 $9,461 $9,882


NoEW $76 $102 $139 $150 $194 $243 $324 $392 $485 $548

AvEW $188 $224 $270 $274 $318 $345 $448 $511 $567 $660

WeuEW $897 $1,106 $1,365 $1,391 $1,606 $1,698 $2,128 $2,320 $2,429 $2,642

Documents

Report on marginal external damage costs inventory of greenhouse