Memorandum 164
Submission from Defra
This submission addresses the following topic
within the Committee's terms of reference for their Geo-engineering
case study: The current and potential roles of engineering
and engineers in geo-engineering solutions to climate change
SUMMARY
- There has been relatively little research
so far into the feasibility and effects of geo-engineering approaches
for mitigating climate change and there are wide-ranging concerns
about their implementation. Despite this, many parties consider
that further research into the feasibility of geo-engineering
options is warranted, as they might provide a way of "buying
time" to reduce greenhouse-gas emissions if those reductions
were not being achieved quickly enough to avoid dangerous climate
change.
- Defra has recently undertaken a preliminary
assessment, informed by a poll of UK experts, of a number of high-profile
geo-engineering options that have been proposed for mitigating
climate change. The options were categorised under either (a)
alteration of the Earth's radiation balance, or (b) removal and
storage of atmospheric carbon dioxide (CO2).
- Defra concludes that there are large uncertainties
regarding the effectiveness, impacts, technical feasibility, cost
and risks of all the geo-engineering schemes considered and that
it is premature to draw firm conclusions on the feasibility of
implementing any of them.
- Although the priorities for tackling climate
change should continue to be overwhelmingly focussed on emissions
abatement and adaptation to unavoidable change already underway,
we consider some further research into the feasibility of using
geo-engineering options could be merited. If research goes ahead,
we have identified a number of desk, field, laboratory and climate
model-based studies as priorities for the research community to
consider.
- We also make some preliminary conclusions
about individual schemes:
- "Air capture" schemes potentially
have fewer detrimental side effects than other options, but their
effectiveness in net CO2 capture is still uncertain.
- Injection of aerosols into the stratosphere
or troposphere, surface albedo modification, ocean iron fertilisation
and "air capture" schemes have the advantage that they
could be implemented gradually and altered relatively easily.
- Options involving space shades/mirrors
(high risk and an unlikely prospect in the near term) or injection
of aerosols into the stratosphere or troposphere have the disadvantage
that rapid climate change could result if they were stopped abruptly.
- Ocean pipes and cultivation of marine
algae were considered to have limited feasibility.
- Schemes that change the Earth's radiation
balance have the disadvantage that they do not counter ocean acidification
or other negative effects of increasing CO2 concentrations.
- The climate system and ecological impacts
of most, if not all of these schemes, are currently highly uncertain
and as such they would be associated with high environmental risks.
INTRODUCTION
1. Geo-engineering, defined here as intentional
large-scale manipulation of the global environment, has been suggested
as a means of mitigating the effects of anthropogenic greenhouse-gas
emissions on climate, without necessarily reducing emissions.
The topic is currently attracting significant interest. However,
to date there has been relatively little research into the feasibility
and effects of such large-scale manipulations, and there are wide-ranging
concerns about their implementation.
2. This submission is informed by a Defra
assessment paper on a number of high-profile geo-engineering options
for mitigating climate change. The paper was prepared after polling
a range of UK experts for their views and comments, and has been
shared with the Royal Society.
BACKGROUND
3. Defra has not, so far, undertaken any
research into geo-engineering; its limited assessments of the
topic have been informed by:
- the IPCC's Fourth Assessment Report (AR4),
published in November 2007, which concluded that geo-engineering
options are largely unproven and potentially high risk;
- Defra-funded science undertaken at the
Met Office Hadley Centre; and
- informal comment from the U.K. climate
science community.
4. Potential concerns about the implementation
of geo-engineering schemes include:
- our incomplete understanding of the Earth
system means it is impossible to understand fully the potential
impacts of any geo-engineering scheme;
- geo-engineering schemes based on changing
the Earth's radiation balance do not counter the other negative
effects of increasing CO2 concentrations, such as ocean acidification
(which could have significant detrimental effects, including threats
to marine productivity and biodiversity);
- many geo-engineering schemes, if implemented,
would need constant maintenance to retain their effect, which
could be extremely expensive and/or impractical; and, in the event
of funding for maintenance ceasing to be available, the environmental
implications could increase significantly;
- consideration of geo-engineering options
could divert funding, public attention, and specialist engineering
expertise away from other policies and projects, including those
aimed at reducing greenhouse-gas emissions;
- gaining public acceptance and international
agreement on geo-engineering schemes could be difficult; and
- in some cases, it is unclear how funding
for schemes could be generated, particularly where there are significant
uncertainties around the extent of the mitigation effect or of
other environmental consequences, or where it is unclear how the
developer of a technology would be able to reap an economic benefit.
5. Despite these concerns, many parties
feel that further research into the feasibility-in relation to
the effectiveness, impacts, technical feasibility, cost and risks-of
geo-engineering options is warranted because these options could
offer a means of "buying time" to reduce greenhouse-gas
emissions if those reductions were not being achieved quickly
enough to avoid dangerous climate change. It is also worth noting
that some geo-engineering schemes could have beneficial side effects
such as increases in agricultural and forest productivity due
to CO2 fertilisation (in the case of schemes that do not reduce
atmospheric CO2 concentrations) and/or increases in diffuse radiation
(in the case of schemes that modify the properties of the atmosphere).
GEO-ENGINEERING
OPTIONS
6. The following geo-engineering schemes,
grouped into two categories, were considered in the Defra assessment
paper:
Alteration of the Earth's radiation balance
- Space shades or mirrors positioned in space
between the Earth and the Sun to reduce the amount of sunlight
that reaches the Earth;
- Aerosol[24]
injection into either the stratosphere (upper atmosphere, where
aerosols have a cooling effect by backscattering solar radiation)
or troposphere (lower atmosphere, 0-15 km, where aerosols can
increase cloud albedo[25]);
and
- Changes in the land/ocean surface to modify
the albedo of natural or artificial surfaces.
Removal and storage of atmospheric CO2
Involves capturing CO2 from the atmosphere through:
- Ocean fertilisation to increase phytoplankton
growth and associated carbon "removal" eg by adding
iron or by "pumping" ocean water to near the surface
using pipes;
- "Air capture" schemes such as
"synthetic trees", which can chemically capture and
remove CO2 from the atmosphere;
- Electrochemically-induced increases in
ocean alkalinity; and
- Marine-algae cultivation.
7. "Carbon Capture and Storage"
options or schemes that aim to increase the length of time that
carbon stored in non-atmospheric reservoirs is isolated from the
atmosphere (such as the addition of "biochar" to soils
or the disposal of agricultural crop waste in the ocean), were
not included, because these are not routinely considered to be
"geo-engineering" approaches.
MAIN FINDINGS
8. The Defra assessment paper concentrates
on science and technological issues. Whilst the paper recognises
that socio-political and economic issues may be crucial for delivery
of geo-engineering options and identifies a number of these related
issues, it does not consider them formally.
9. Defra concludes that there are large
uncertainties regarding the effectiveness, impacts, technical
feasibility, cost and risks of all the geo-engineering options
schemes it considered; and that it is premature at this stage
to draw firm conclusions on the feasibility of implementing the
schemes discussed. However, the following preliminary conclusions,
in relation to scientific and technological aspects of individual
schemes, can be drawn:
- options involving space shades/mirrors
(particularly those that involve significant engineering in space)
are unlikely to be available in the near future and (as they stand
at present) would be high-risk compared to other options because
they would be difficult to modify or remove;
- ocean pipes are probably not a feasible
geo-engineering option because they are unlikely to remove significant
quantities of CO2 from the atmosphere (and could result in CO2
release);
- cultivation and storage of marine algae
is unlikely to be a feasible option for mitigating climate change
on a large scale due to practical difficulties associated with
storing algal biomass, but it might be possible to combine small-scale
storage operations with other processes, such as biofuel production;
- options involving space shades/mirrors
and injection of aerosols into the stratosphere or troposphere
have the disadvantage that rapid climate change could result if
they were stopped abruptly (either due to failure or policy decisions);
- injection of aerosols into the stratosphere
or troposphere, surface albedo modification, ocean iron fertilisation
and "air capture" schemes have the advantage that they
could be implemented gradually and modified or stopped relatively
easily; and
- "air capture" schemes potentially
have fewer detrimental side effects than other options, but their
effectiveness in terms of net CO2 sequestration/release remains
uncertain.
10. The challenge of significantly reducing
greenhouse-gas emissions is great and the risks associated with
failing to do so are high. There is therefore an argument for
carrying out further research to assess the feasibility of using
geo-engineering options to "buy time" to reduce greenhouse-gas
emissions in case the global community cannot reduce emissions
quickly enough to avoid dangerous climate change; although, given
the significant doubts over feasibility, it is essential not to
rely on the availability of geo-engineering options. Research
into the scientific, technological, economic, and socio-political
aspects of geo-engineering options would be necessary to bring
deployment closer to reality. A number of desk, field, laboratory
and climate model-based studies are identified as priorities for
the research community to consider:
- Field-based studies to explore the effects
(desired and undesired) of (i) changing surface albedo and (ii)
spraying seawater into the troposphere.
- Model- and laboratory-based studies to
understand the atmospheric chemistry (particularly ozone) involved
in injecting sulphate aerosols into the stratosphere.
- Climate model-based studies to explore
the effects of (i) changing surface albedo, (ii) spraying seawater
into the troposphere, and (iii) injecting sulphate aerosols into
the stratosphere. A particular priority in this regard could be
to use more "realistic" scenarios (such as simulating
aerosol injection using fully-coupled General Circulation Models
that include atmospheric chemistry, rather than using "solar
dimming" to represent the effects of aerosols). Simulations
could also explore the effects of different options for applying
the schemes, such as Arctic vs tropical and pulsed vs continuous
injection of sulphate aerosols into the stratosphere.
- Climate model-based studies to determine
the optimal "mix" of geo-engineering schemes (ie the
combination that maximises desirable effects and minimises detrimental
effects).
- The use of observational data to validate
climate model results (for example, the use of satellite data
to validate simulations of changes in surface albedo).
- Research into the net effect on atmospheric
CO2 concentrations of schemes that require significant amounts
of energy to implement-particularly (i) electrochemically increasing
the alkalinity of the ocean, and (ii) "air capture"
schemes such as "synthetic trees".
- Research to assess the technical and economic
feasibility of options, particularly where the science is relatively
well-understood (such as changes in surface albedo).
- Research into the socio-political feasibility
of options, particularly for schemes that involve modification
of privately-owned property (such as increasing the albedo of
urban surfaces) and schemes that would probably require universal
political agreement to implement (such as space shades/mirrors
and injecting sulphate aerosols into the stratosphere).
OTHER CONSIDERATIONS
11. Defra recognises that socio-political
and economic, as well as scientific and technological, issues
will need to be considered when assessing the feasibility of geo-engineering
options; for example:
- There should be a measurable benefit that
unambiguously outweighs the impacts arising from the full lifetime
energy costs, carbon emissions and other adverse consequences
involved in establishing, maintaining and decommissioning the
relevant technologies.
- The magnitude of the manipulation must
be controllable, and it must be easy to "switch off"
the effect (in the event of unforeseen consequences).
- There must be very wide public acceptance
and international agreement on the acceptability of geo-engineering
schemes. The following political issues must be addressed if geo-engineering
is to be carried out on a globally-significant scale:
(i) There needs to be high public trust in
both the science/technology and the competence of the implementing
bodies (private sector, national governments or international
agencies), which may be difficult to achieve. It is, therefore,
important that the factors that influence public understanding,
risk perception and acceptance of such options are understood
and taken into account before attempting to implement them.
(ii) Geo-engineering actions by one country
must not be regarded as an infringement or incursion on the territory
of another (although it is worth noting that greenhouse-gas emissions
have such effects). This may be particularly relevant to atmospheric
manipulations, which affect national airspace and need to be large-scale
to have significant effects.
(iii) Political commitment needs to be sustained
over the period for which geo-engineering is required.
(iv) Even if there is international acceptance
that a net global benefit will result, it must be recognised that
disadvantages may occur for some countries. Multi-billion dollar
compensation could be involved between winners and losers (for
example, the latter suffering floods or droughts potentially attributable
to geo-engineering). The ethical and legal frameworks for such
arrangements do not yet exist, and are unlikely to be straightforward.
(It is worth noting, however, that this concern is unlikely to
be significant for geo-engineering options that significantly
reduce CO2 concentrations and thus directly reduce the impacts
of greenhouse-gas emissions.)
- The way in which the cost of the scheme
would be met must be considered (particularly as the benefits
would ideally be shared by all).
- If CO2 reductions obtained through geo-engineering
schemes were to be traded as carbon credits in carbon trading
schemes, the principles and practices for verifying the value
of such credits must be agreed between the scientific, commercial,
and regulatory communities; and we would need to avoid situations
where climate benefits were rewarded whilst any adverse environmental
effects (such as biodiversity impacts), which might not be experienced
by the developer or deployer of the technology, were not paid
for.
- Considerable resources would probably need
to be expended to offset even a small fraction of predicted climate
change. While this benefit could complement other measures, the
possibility that geo-engineering options could divert attention
and resources away from more fundamental solutions to global warming
(ie emissions reductions and avoiding deforestation) must be considered.
CONCLUSIONS
12. It is clear that, given the significant
uncertainties surrounding geo-engineering options, research funding
has a high probability of not leading to the development of useable
technologies. Any public support for geo-engineering research
should therefore be understood in the context of the wider effort
to tackle climate change, the priorities for which should continue
to be overwhelmingly focussed on emissions abatement and adaptation
to unavoidable change already underway. Defra currently has no
plans for significant research funding on geo-engineering; however,
if other parties, countries and institutions wished to develop
a shared approach, Defra would be interested in sharing expertise,
and in helping to develop an initial detailed scoping study.
13. The Committee asked some specific questions
on the role of engineering and engineers in geo-engineering, and
on the relationship with research conducted on the reduction of
greenhouse gas emissions. It is clear that the profession is vital
to tackling the problem of climate change, and that success will
depend in large part on society's ability to develop and deploy
innovative solutions. Climate change mitigation and adaptation
should therefore form a significant focus for the engineering
profession, and for university courses and other training for
the profession; and that climate change policy in the UK needs
engineers. However, Defra considers that geo-engineering should
not be considered a priority for the engineering profession's
contribution to tackling climate change, compared with the overwhelming
need to develop and deploy methods for the abatement of greenhouse-gas
emissions and the need to adapt to the levels of climate change
to which the world is already committed.
September 2008
24 Sub-microscopic particles. Back
25
Proportion of sunlight reflected. Back
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