Carbon Offset, Carbon Reduction
Paying for
carbon offsets is sometimes represented as an easy way for those with
sufficient means to keep a clear conscience while maintaining a life style that
produces high carbon emissions. This issue is discussed by Bourban and Broussois
(2020) in their constructive criticism of the Effective Altruism movement and
its search for the most effective ways to benefit others. The paper uses carbon
offsets as an illustration of attitudes to individual responsibility. The
authors cite a calculation showing that “an American’s annual emissions could
be offset for a mere $300/year”, so that if “you earn enough money, you can
donate some of it, without having to make any sacrifice, and get off the moral
hook.” They also quote a suggestion that ‘rather than reducing your own
greenhouse gas emissions, you pay for projects that reduce or avoid greenhouse
gas emissions elsewhere’. This use of carbon offsets is contrasted with the
view that personal integrity requires action to reduce one’s own carbon
footprint: “Deep transformations in our habits and lifestyles are required, and
financially contributing to offsetting and geoengineering projects will not
help us get there.”
Assessment of
individual carbon footprints can be made using one of the many calculators
available, and the result will often show that changes in travel, diet, and
consumption habits, together with improvement in home energy efficiency, would
bring about substantial reduction in greenhouse gas emissions. What will also
be clear is that the carbon footprint cannot be reduced to zero by these methods,
and that any reductions made affect only future emissions, and do nothing to compensate
for those of the past. Bourban and Broussois acknowledge that many “actions
involving GHG emissions cannot be avoided” and that “in these cases, offsetting
one’s emissions is indeed a good option.” They refer to “the complementarity of
offsetting and reducing one’s emissions”, and part of their criticism of Effective
Altruism is that it “tends to present the first measure as though it was an
excuse to avoid implementing the second.” The complementarity of offsetting and
the reduction of individual emissions will be explored below by comparing improvement
to home energy efficiency with donation to carbon offset charities.
Increased domestic
energy efficiency is a route open to house owners with adequate means who wish
to reduce their carbon footprints. Suitable measures include improved
insulation, low carbon heating methods, installation of solar PV panels and
solar water heating. Some energy saving measures cost little or nothing, others
can be very expensive. A set of figures on overall costs and saved carbon from
house retrofits in the UK is given in the report “Retrofit factfile” from the
Carbon Co-op (2016). The “actual figures from construction and post-completion
monitoring” for five complete retrofits include overall cost and kg CO2 saved
annually. To estimate the cost of the total CO2 saved, we have to supply a time
frame, and an arbitrary but not altogether unrealistic figure of twenty years
will be used here. Using this time frame, the overall costs per unit of CO2 saved
lie in the range £591 to £798 per tonneCO2 saved.
The
recommendations of some house efficiency surveys can allow the cost of carbon
saving by each of several measures to be estimated, when the cost of each
proposed action is accompanied by an estimate of its payback time along with
the corresponding amount of carbon emission avoided annually. By assigning a
time frame as above, a cost for the total carbon saved can be assigned to each
measure, and compared with the cost of carbon offsetting. The range of payback
times is wide, from a year or two for some measures to more than a hundred years
for others; the payback times listed below are taken from a 2014 survey on a
two bedroomed house in the UK. The figures which follow should be regarded as
purely for illustration for a number of reasons: they refer to a single survey;
UK carbon coefficients have changed significantly since 2014; material and installation
costs have changed; and an arbitrary time frame is used.
Simple actions
such as not leaving electrical devices on standby cost nothing and so have zero
payback time; energy saved by replacing an inefficient electric kettle should return the cost in about 2 years; draught
proofing can pay for itself in 7 to 8 years; replacing an old electric oven
with a more efficient model returns the investment in about 50 years; replacing
a single glazed outside door with a modern double glazed door has a payback
time of 140 years; and the corresponding figure for additional above-floor
insulation is nearly 200 years.
For measures
with short payback times, financial self-interest alone is an adequate
motivation, quite apart from the wish to mitigate climate change. For those measures
with long payback times, some exceeding the life expectation of the
householder, concern with climate change is likely to be the main consideration;
if so, the prime figure of interest will be the expected reduction in carbon
dioxide or equivalent emissions. The survey referred to above gave for each of
the proposed measures a figure for its cost divided by the estimated amount of
CO2 saved annually. Like payback times, these figures cover a very wide range. For
simple secondary window glazing using polyester the figure was £0.32 per kg CO2
saved annually; the corresponding figure for replacing existing double glazing
with new double glazing of a high specification was £12.13; that for replacing a
washing machine by a new high efficiency model was £116. (The amount of
embodied carbon does not seem to have been taken into account). Using a twenty
year time frame the carbon dioxide saved by the polyester secondary glazing
will have cost £16 per tonne (i.e. 1000 X £0.32/20); the new double glazing,
£607 per tonne; and the washing machine £5800 per tonne.
Since spending
on those household efficiency measures with very long payback times brings little
financial reward, and is likely to be motivated by ethical and environmental
considerations, it is similar in some ways to making a charitable donation.
There are many charity projects which offer some form of carbon offset in
response to donations, and in some cases a quantitative comparison can be made
between the two approaches to carbon saving. There are of course important differences,
particularly regarding confidence; money spent on home efficiency improvement
buys tangible changes the results of which can be measured over time by the
purchaser, whereas the fulfilment of plans for CO2 reduction made by a charity will
not generally be verifiable by the purchaser, and may be subject to disruptive
influences beyond the control of the charity.
In order to
convince someone whose inclination is to ‘own’ the problem of climate change by
actions such as home efficiency improvement that some of his or her money could
be better spent on carbon offset donations, evidence would be needed on at
least two grounds; first that the organisations offering the offsets are
trustworthy and effective, and second that the quantitative comparison is
compelling. On the first point, some of the uncertainty attached to
philanthropic giving can be reduced by noting the recommendations of
organisations which survey the charitable sector and list those which they
consider to have most impact. On the second point, the high cost of saving CO2
attached to some elements of home energy efficiency suggest that it is possible
to tilt the complementarity referred to by Bourban & Broussois too far in
the direction of reducing one’s own emissions, and that beyond a certain point money
would be better used on offsetting them. The figures supplied by some
offsetting organisations seem to confirm this suggestion, and details follow.
Giving Green
(n.d.) is an organisation which offers “an evidence-based guide to help donors
and volunteers fight climate change.” It is largely focussed on America and identifies
two current key areas: “Carbon Offsets, which seek to cause immediate,
verifiable decreases of greenhouse gases (GHGs) in the atmosphere; and US
Policy Change, which aims to change US policy to drive considerable reductions
in emissions”. Efforts to change US policy, though no doubt important, cannot
be evaluated in terms of the cost of carbon saved; however the three following carbon
offset projects recommended by Giving Green do provide figures of this kind.
Climeworks
(2020) is a Switzerland-based company that removes CO2 from the atmosphere at
fourteen facilities using Direct Air Carbon Capture and Sequestration (DACS). The captured CO2 is then turned into “solid
material deep underground”. While donors may therefore feel a high degree of
certainty that their gifts do secure carbon sequestration, the cost is high, at
about £880 per tonne of CO2; donations do however also support the development
of DACS technology.
Tradewater (n.d.)
sets out “to fight climate change by collecting and destroying the most
powerful greenhouse gases in the world.” These are refrigerants and “other
gases with warming potential up to 10,000 times that of carbon dioxide.” The
price of CO2 equivalent prevented from reaching the atmosphere is about £11 per
tonne, and Giving Green regards the organisation as offering “one of the most
attractive combinations of price and certainty.”
BURN (n.d.)
“makes and distributes fuel-efficient stoves in Kenya. Their impact on fuel
usage (and therefore GHG emissions) was validated by a recent randomized controlled
trial … which sets it apart from the mixed results of other cookstove
providers. Additionally, BURN stove users see large reductions in expenditure
on fuel, leading to more money for the family.” The price of offsetting a tonne
of CO2 is estimated at between £7 and £8.
The range of
offsetting costs represented by these three organisations is thus from about £7
to £880 per tonne of CO2; the range of average overall costs from the retrofit
study on a 20 year time frame is from £591 to £798 per tonneCO2 saved; and the
range of costs of individual measures from a home efficiency survey on the same
time basis is from about £16 to £5800 per tonne CO2. These figures should all
be treated as approximate and illustrative; the only recommendation made here is
that there is a case for considering whether money intended for those home
efficiency improvement measures which have very high costs per unit of CO2
saved might not be better used to fund charity projects which claim to save CO2
much more cheaply. Such charities may also be relevant in addressing the
environmental damage done by an individual’s past carbon emissions, and the
ongoing residual greenhouse gas emissions which cannot be entirely eliminated
by changes in lifestyle.
References
Bourban, M.,
and Broussois, L. (2020). “The Most Good
We Can Do or the Best Person We Can Be?” Ethics,
Policy & Environment
DOI:
10.1080/21550085.2020.1848175
Viewed 19th
Jan 2021:
https://www.academia.edu/26828788/The_Most_Good_We_Can_Do_or_The_Best_Person_We_Can_Be
BURN (n.d.).
Viewed 19th
Jan 2021:
Carbon Co-op
(2016), “Retrofit factfile”, URBED, Carbon Co-op
Viewed 20th
Jan 2021:
Climeworks
(2020).
Viewed 19th
Jan 2021:
Effective Altruism
(n.d.).
Viewed 19th
Jan 2021:
https://www.effectivealtruism.org
Giving Green
(n.d).
Viewed 19th
Jan 2021:
https://www.givinggreen.earth/
Tradewater (n.d).
Viewed 19th
Jan 2021:
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