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https://authors.elsevier.com/sd/article/S1364-0321(21)00381-6
John was system economics lead in Oxford Martin School Integrate programme now morphing into new ZERO Institute. Former Chief Economist, UK Electricity Council, consultant for World Bank, and Chair BIEE climate policy seminars. Short topical posts: HOME AND BLOG page. Click BLOG below photo for recent blogs, or blogs by topic. Navigation bar links to longer individual commentaries, eg SCIENCE VS SCEPTICS, or SITE NAVIGATION. To comment on a post, click on "comments" at end of that post.
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What Matters Most? Population, GDP Growth or Technology.
A common theme in popular
discussion of climate change, or rather of whether mitigation is feasible, is its
attribution to different factors, notably population growth or economic growth,
and the reliance of solutions on technology. This also affects any discussion
of historic responsibility for CO2 emissions. It is a highly emotive subject,
particularly in relation to population control or the limitation of growth, so
it is at least worth a cursory look at what the hard statistics tell us.
The so-called IPAT equation
represents a general description of human influence on the environment: IMPACT
(of CO2) = [POPULATION] X [AFFLUENCE] X [TECHNOLOGY]. A popular
and useful way of interpreting this for CO2 emissions for the energy
sector is the so-called Kaya Decomposition. Affluence is measured as GDP per
capita and technology is further decomposed as energy per unit of GDP, and CO2 emitted
per unit of energy. The Kaya identity[1] is:
Global Picture. The IPCC Fifth Assessment Report (2014) provided a useful breakdown of changes in global CO2 emissions over several decades, based on this identity:
In the three
decades from 1970 to 2000, population growth and increasing incomes contributed
similar amounts to the rise in emissions, but the energy intensity of GDP fell
quite sharply contributing a significant saving to the level of emissions that
might otherwise have been expected.
The energy
intensity of GDP was a significant offsetting factor, whose importance rose in
1990-2000, possibly reflecting the longer term impact of higher energy prices
and uncertainties in the 1970s and 1980s. However efforts to reduce the carbon
emissions associated with energy use played only a limited role in reducing
emissions. This is unfortunate since reduction of dependence on fossil fuels this is a key component of emissions reduction
hopes, and this factor actually moved in the wrong direction from 2000-2010, again
reflecting in part the Chinese dependence on coal.
From 2000 to
2010 the importance of rising incomes rose relative to population factors,
reflecting inter alia the rapid growth of the Chinese economy. The overall outcome
was particularly depressing as the decade showed a sharp increase in emissions
and lessening impact of the mitigating factors.
Major
regional and temporal differences
But this
decomposition can change significantly over time. Global averages also conceal
major differences between countries, and
there are some optimistic signals. A similar but more recent chart for China (Safonov
reference below) shows overall reductions (to 2016), and significantly more
reductions attributable to less energy intensive GDP and less carbon intensive
energy. For China, population growth has not been a significant factor over
this period, but income growth continues to be so.
Similarly
more optimistic trends have been observed in the USA to 2015, but with higher
influence from population, less from economic growth, and significant
reductions attributable to less energy intensive GDP and less carbon intensive
energy consumption.
An
interesting comparison of country by country decomposition for periods before
and after the financial crash of 2008 is given in a fairly recent paper by
Sadorsky, referenced below. It shows huge diversity in findings between
countries, exemplified in the following chart for four countries:
NB.
This chart has a rather more complex interpretation, as it represents the changes between two very distinct
periods. The reader is referred to the Sadorsky article
Kaya factors.
The future.
Given the
pace of reduction required to reach net zero by 2050, the Kaya emphasis will
have to shift to much greater emphasis on decarbonising energy. Population
cannot be subject to substantial percentage reduction, and the drive for higher
incomes is unlikely to stop. There is some scope for further weakening of the
link between affluence and energy use, but the heavy lifting will depend very
substantially on decarbonisation of energy, starting with the power sector and
expanding the power sector into transport and heating.
References:
IPCC Fifth
Assessment Report.
George Safonov's Lab. National Research University
Higher School of Economics, Moscow. Long-term, Low-emission Pathways in
Australia, Brazil, Canada, China, EU, India, Indonesia, Japan, Republic of
Korea, Russian Federation, and the United States. December 2018.
Sadorsky, P. Energy
Related CO2 Emissions before and after the Financial Crisis. Sustainability 2020, 12,
3867. https://doi.org/10.3390/su12093867
Dr Ajay
Gambhir, Neil Grant, Dr Alexandre Koberle, Dr Tamaryn Napp. The UK’s
contribution to a Paris-consistent global emissions reduction pathway. Grantham
Institute. Imperial College. 2 May 2019.
Public Utilities
Fortnightly. First Look at 2015 CO2 Emission Trends for the U.S.
For a fuller “actuarial
explanation and justification for the Kaya identity, this reference may help Kaya
identity_JC Final 050219.pdf (actuaries.org.uk)
[1]
Since the identity is multiplicative, a logarithmic transformation is usually
used in the calculation of the factor contributions.
Here are some back of the envelope calculations that demonstrate the credibility of the assertion that action to mitigate climate change, and progress to a low carbon economy, can be achieved at a containable cost. It aims to provide a simple intuitive defence of conventional estimates for the general reader, but serious students of the subject are invited to delve deeper into some of the excellent material produced under the aegis of the Committee on Climate Change[1].
One of the arguments mounted
against taking effective action on climate is that the economic cost is
unaffordable. The obvious response is that this has to be compared with the
cost of not taking action, the costs of adaptation, and the possibility of
existential climate threats on an unimaginable scale. However rather than
engage with the occasionally hysterical accusations of alarmism from those in
denial on the climate science, it is worth trying to get a sense of the scale
of what may be involved in meeting a UK zero carbon target by 2050. Some sense
of proportion should start to defuse the issue and calm any fears of national
bankruptcy.[2]
This can be a confusing
exercise, not least because estimates (of mitigation costs) tend to get tossed
around in very different contexts. For example, it’s most common for costs to
be discussed in very broad terms as a percentage of GDP. The Stern Review
indicated costs of up to 2.0 % of GDP per annum, and some people have argued
that this would be a very damaging and unsustainable burden in macro-economic
terms. The Committee on Climate Change
currently makes a similar estimate (of 1-2 % of GDP). Others argue that Green
investment can actually be used to boost economic growth and domestic
employment[3]. There can be at least a
partial truth in this argument, even if it can be misrepresented as arguing
that the low carbon economy pays for itself. It is not an argument I intend to
deploy here.
Some will be more concerned
with the public expenditure implications, although that issue should be seen
much more in terms of more political questions of how we choose to fund
transformational change. For example, much of the cost of transition to low
carbon may be carried by private consumers, in their utility bills or more
expensive motoring choices, or it may include publicly funded infrastructure
investment and extensive grants and subsidies.
Macro-economic shocks and UK GDP
numbers
2019 GDP (last year before
pandemic) £ 2170 billion pa
Estimated permanent loss of
GDP due to 2008 financial crisis £
300 billion pa
The economy is 16%, or £300 billion, smaller than it would have
been had it followed the pre-crisis trend. (IFS 2018[4])
Typical impact of an oil price
shock[5] in 1970s, 1980s and 1990s. £ 100 billion pa
(an order of magnitude estimate, based on spikes and falls in
the oil price of $100/ bbl, UK consumption of 100 mn tonnes pa,
and scaling up to an equivalent percentage of 2019 GDP)
I have not included the significantly
larger shifts in resources associated with different government priorities on
taxation and spending. Even so, the conclusion we might draw here is that the
expenditure on a low carbon economy, while substantial, is far from
catastrophic and unmanageable when viewed in macro-economic terms. We have
coped with much larger and less predictable economic shocks than what we now
face in eliminating emissions.
Public expenditure choices
Expenditure budget 2021: £
908 bn.
Defence £ 54 bn pa
Defence in 1951 (Korean War) accounted
for
10% of GDP. Equivalent percentage of 2019 GDP £
217 bn pa
Overseas aid (0.7% of GDP
target) £ 15 bn pa
Overseas aid (after current
cuts) £ 10.85 bn pa
Reported cost of UK Track and
Trace system[6] £ 37 bn
(spread over two years but seems to be essentially
a 12 month figure). Minimal identified benefit.
Assumption of a 2% of 2019 GDP
devoted to GHG £
43 bn pa
reduction and low carbon transition. (as above)
But what can you buy for 2% of
GDP?
It turns out you can do quite
a lot for decarbonisation with around £ 40 billion a year. Here is one
allocation of that money:
Decarbonising the power
sector. £
18 bn pa
Retrofitting UK housing stock.
28 million households £
20 bn pa
Grant of £ 20,000 per household for retrofitting, at one million
households a year for 28 years
Charging infrastructure for
electric vehicles (EVs) £
2.5 bn pa
Total £
40.5 bn pa
This covers the three main
sources of UK emissions, and the main areas for investment to achieve net zero
by 2050. Assumptions to justify the plausibility of these numbers are as
follows
Power Sector
Sizewell C has an estimated
capital cost of around £ 18 billion for 3.2 GW of capacity. Nuclear is
currently regarded as one of the more expensive options for low carbon
capacity, and Sizewell is “first of a kind” but this at least gives us an order
of magnitude. The equivalent of one Sizewell a year for 25 years delivers
around 80 GW of capacity and more than 600 TWh pa of energy, more than enough, even
after allowing for significant growth, to effectively decarbonise a power
sector which already has a significant proportion of renewable low carbon
energy. [Current UK annual consumption less than 350 TWh]
Alternative renewable sources
are also widely seen as likely to be much cheaper than this, although there
will be other major costs associated with energy storage. However we might
interpret this as at least a first approximation, or an upper limit to the
capital cost for low carbon generation. A great deal of new investment would of
course be required in any case, so much of this will not be a truly incremental
cost.
Heating of buildings
Retro-fitting of buildings,
especially residential property, for energy efficiency and low carbon heat
pumps or heat network solutions, is one of the biggest problems for achieving
zero carbon. The cost of air or ground source heat pump installations are
currently advertised at around £ 6000-8000 and up to £ 16000 respectively,
while heat networks are collective typically municipal investments which can
also be quite costly. But even adding on a substantial allowance for insulation
improvement, £ 20000 per household would look like an extremely generous grant
to a householder, especially as there would be a continuing benefit in lower
running costs.
Electric vehicles
“The UK by 2040 needs 1-2.5
million new charging points. An average public charging point costs 25-30,000
euros so it would need to invest 33-87bn euros from now until 2040,” said Wood
Mackenzie’s Wetzel. Interpreting this as two million over twenty years and assuming
a cost per installation of £ 25000, this implies an annual investment of £ 2.5
billion.
The price of EVs is likely to
fall dramatically with increasing scale, so we should not need to worry unduly
about the capital costs of fleet replacement, which will be borne by motorists
as they retire their existing vehicles.
Conclusions
Current estimates of
expenditure required for a zero-carbon economy are plausible. In no sense can
they be considered unattainable or damaging in macro-economic terms, as the
sums are smaller and more predictable than the much bigger economic shocks we
have endured in recent decades from other sources. Viewed as public expenditure
choices the sums are commensurate with other choices we make and have made,
such as the unfortunate “test and trace” scheme. An it is quite easy to
hypothesise major elements in the composition of that expenditure.
Caveat. Sharp-eyed
readers will have noticed that I have omitted some of the notoriously
difficult, but smaller, sectors, such as aviation and shipping. But I believe
the biggest additional issue will be the funds that high income countries will
need to find in order to support low carbon strategies in the developing
world. That is a different story, and
one that I have addressed in earlier posts this year.
[2]
This post concentrates on UK statistics but the same arguments, and similar
orders of magnitude, will apply to most developed economies.
[3]
Retrofitting the UK housing stock, and many other infrastructure investments,
will be labour intensive.
[4] 10 years on - have we
recovered from the financial crisis? - Institute For Fiscal Studies - IFS.
Paul Johnson and Jonathan Cribb. 2018
[5]
The UK became a net oil exporter during this period, so the macro-economic
consequences for the UK relate both to price shocks and significant changes in
production.
[6] “Chancellor
Rishi Sunak’s Budget last week included an additional £15bn for test and trace,
taking the total bill to more than £37bn over two years.” [Independent. 10
March 2021]