Urgent need for post-growth climate mitigation scenarios

Abstract

Established climate mitigation scenarios assume continued economic growth in all countries, and reconcile this with the Paris targets by betting on speculative technological change. Post-growth approaches may make it easier to achieve rapid mitigation while improving social outcomes, and should be explored by climate modellers.

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Urgent need for post-growth climate mitigation
scenarios
Established climate mitigation scenarios assume continued economic growth in all countries, and reconcile this
with the Paris targets by betting on speculative technological change. Post-growth approaches may make it easier
to achieve rapid mitigation while improving social outcomes, and should be explored by climate modellers.
Jason Hickel, Paul Brockway, Giorgos Kallis, Lorenz Keyßer, Manfred Lenzen, Aljoša Slameršak,
Julia Steinberger and Diana Ürge-Vorsatz
As the world faces the reality of
climate breakdown, citizens, social
movements and governments are
grappling with how to respond. But so far
the public debate has been constrained
mostly to the policy options that
are represented in existing climate
mitigation scenarios.
Existing scenarios start with the
assumption that all nations should continue
to pursue economic growth for the rest of
the century, regardless of how rich they have
already become. Growth is an unquestioned
norm1. This creates a problem because
growth is projected to drive a significant
increase in energy demand over the coming
decades, making it more challenging to
decarbonize the economy2. To reconcile
growth with the Paris Agreement goals of
keeping global warming below 1.5 °C or
2 °C, existing scenarios gamble on dramatic
technological change, particularly negative
emissions technologies and productivity
improvements big enough to drive absolute
decoupling of gross domestic product
(GDP) from energy use.
In recent years, however, scientists have
raised substantial empirical questions about
the risks of negative emissions technologies
and the feasibility of achieving sufficient
absolute decoupling, warning that these
approaches may not be adequate to address
the crisis we face3.
Recognizing these challenges, ecological
economists have proposed an alternative
approach. For high-income countries,
continued economic growth may not
be necessary. Instead, they can adopt
post-growth policies, which are designed to
keep economies stable and support strong
social outcomes without economic growth4.
Policymakers commonly regard
economic growth as a proxy for human
development and social progress. But
past a certain point, which high-income
nations have long exceeded, the correlation
between GDP and social indicators breaks
down or becomes negligible. For instance,
Spain significantly outperforms the USA
in key social indicators (including a life
expectancy that is five years longer),
despite having 55% less GDP per capita.
When it comes to achieving strong social
outcomes, what matters is not a continuous
increase in commodity production, but
access to livelihoods and provisioning.
In high-income countries, delivering the
latter does not require additional growth;
rather, it requires a fairer distribution of
income and wealth, and guaranteed access
to universal public services. Post-growth
scholarship demonstrates that by organizing
the economy around principles of equity
and sufficiency, societies can deliver
high levels of human well-being with
significantly less energy and resources than
rich countries presently use5,6.
Post-growth policies are powerful
because they would make it possible to
achieve the Paris climate goals without
having to rely so heavily on negative
emissions technologies or productivity
improvements7. So far this approach
has not been modelled in mainstream
climate mitigation scenarios, however.
To honour the precautionary principle, and
in order to facilitate a public discussion
about alternative pathways, the range of
scenarios should be expanded to include
post-growth futures.
Risky assumptions
To achieve emissions reductions consistent
with the Paris Agreement, while respecting
the principles of equity and common but
differentiated responsibility, high-income
nations need to pursue dramatic emissions
Credit: David Tran/Alamy Stock Photo
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reductions8. If we assume that high-income
nations continue to grow at usual rates, they
will need to decarbonize their economic
output by more than 12% per year. This
represents a significant challenge, given
that the few countries that have absolutely
decoupled GDP from emissions (such as the
UK, Spain and Romania) have on average
achieved decarbonization rates of only 3.4%
per year from 2005 to 20159.
To reconcile growth with the Paris
Agreement goals, the majority of scenarios
reviewed by the Intergovernmental Panel
on Climate Change (IPCC) rely heavily
on the assumption that negative emissions
technologies — mostly bioenergy with
carbon capture and storage (BECCS) — will
be scaled up later this century to remove
excess carbon from the atmosphere. This
assumption has come under significant
criticism in recent years, however. Scaling
BECCS would require massive amounts
of agricultural land and water for biofuels,
which raises questions about land and
water availability, competition with food
production, emissions from land-use
change, water depletion and biodiversity
loss10. Alternative carbon removal strategies
such as direct air carbon capture and
storage (DACCS) may avoid some of these
problems, but could use up to 50% of the
world’s current electricity generation to
achieve the carbon removal rates assumed in
existing scenarios, making it more difficult
to decarbonize global energy supply11. In
both cases, there are questions about the
availability of sufficient storage capacity for
captured carbon12.
In light of these uncertainties, scientists
increasingly regard reliance on negative
emissions technologies to be speculative
and risky8,13–15. If this approach fails,
we will be locked into a high-temperature
trajectory from which it would be
impossible to escape. It is also worth
noting that even if BECCS or DACCS were
to succeed at scale, this might address
emissions but it would do nothing to address
overshoot of other planetary boundaries,
such as land-use change, biodiversity loss
and biogeochemical flows, all of which are
being exacerbated by rising resource use.
Relying on negative emissions technologies
is not an ecologically coherent approach to
the crisis we face.
If we dial down our assumptions about
negative emissions, the only way to achieve
the Paris climate goals is to significantly
reduce energy demand, making it easier
to accomplish rapid decarbonization. This
approach is represented in a number of
existing scenarios, and is exemplified by the
low energy demand (LED) scenario that was
highlighted in the IPCC’s Special Report on
1.5 °C (ref. 16). In this scenario, global
final energy demand declines from
400 EJ yr–1 to 245 EJ yr–1 in 2050, with these
reductions accomplished in large part by
declining resource use, particularly in the
Global North.
The principle of reducing energy and
resource use represents a safer and more
ecologically coherent approach to climate
mitigation. But because the LED and other
low-demand scenarios developed with
Integrated Assessment Models presuppose
continued GDP growth, they can only
achieve these reductions by assuming a
dramatic absolute decoupling of global
GDP from energy and resources. In the
LED scenario, for example, improvements
in annual energy intensity (energy
consumption per unit of GDP) increase
from 1.5% per year (the average from 2010
to 2020) to a staggering 5.2% per year during
the next decade. Similar assumptions feature
in other high-decoupling scenarios reviewed
by the IPCC17.
Several studies have raised questions
about the feasibility of achieving absolute
decoupling on the scale required by these
scenarios. Empirical evidence demonstrates
a strong relationship between GDP and
energy use18. Relative decoupling has been
occurring for most countries, particularly
high-income countries, but we must be
mindful of the extent to which the latter is
an effect of the geographical disjuncture
between where production takes place and
where GDP is captured. At regional and
global levels, there is no evidence of absolute
decoupling18, and modelled projections
indicate that with existing growth
trajectories, absolute reductions in energy
use are unlikely to be achieved19.
One possible reason for this is that in
a growth-oriented system, productivity
improvements are leveraged to expand
production and consumption20, often
leading to large rebound effects that are
not accounted for in existing scenarios17,21.
These conclusions hold despite a significant
shift to services and digitalization over
the past decades. In fact, tertiarization in
industrialized countries22, as well as the
efficiency improvements achieved through
digitalization23, have led to increases in
energy use and CO2 emissions.
The same is true when it comes to
resource use. The empirical record
demonstrates a strong relationship between
GDP and material footprint18, and modelled
scenarios show that under growth-as-usual
conditions absolute reductions in resource
use are unlikely to be achieved at a global
level even with dramatic efficiency
improvements, in large part because of
rebound effects3.
The post-growth alternative
Given these uncertainties, it is possible
that existing approaches may fail to
deliver the mitigation that is required to
achieve the Paris climate targets. It makes
sense therefore to consider alternative
post-growth scenarios that would reduce
the pressure to rely so heavily on negative
emissions and absolute decoupling.
Towards this end, we can build on the core
insights of the low-demand scenarios,
accepting that significant reductions of
energy and resource use are necessary
in order to make rapid decarbonization
feasible, while pursuing sufficiency-oriented
policies in addition to efficiency
improvements to get there.
Post-growth scholarship calls for
high-income nations to shift away from
pursuing GDP growth and to focus
instead on provisioning for human needs
and well-being, such as by reducing
inequality, ensuring living wages, shortening
the working week to maintain full
employment, and guaranteeing universal
access to public healthcare, education,
transportation, energy, water and affordable
housing. This approach enables strong
social outcomes to be achieved without
growth, and creates space for countries to
scale down ecologically destructive and
socially less necessary forms of production
and consumption, as proposed by
degrowth research24.
In high-income nations, possible policy
interventions might include the following.
In the transportation sector:
shifting from private cars to public and
non-motorized transportation; and
reducing air travel in a fair and just way, for
example by removing subsidies for aviation,
equalizing or increasing taxes on aviation
fuels compared with those of land transport,
and introducing frequent flyer levies or a
rationing framework.
In the industrial sector: extending
product lifespans through warranty
mandates, rights to repair, and regulations
against planned obsolescence; incentivizing
and institutionalizing second-hand
product purchases over new; regionalizing
production and consumption where possible
to reduce freight; limiting advertizing; and
shifting taxes from labour to resources.
In the agricultural sector: minimizing
food waste; reducing industrial production
of ruminant meat and dairy, while shifting to
healthier plant-based diets; and prioritizing
agroecological methods to sequester carbon
and restore biodiversity.
In the buildings sector: promoting
maintenance and retrofits over new
construction; improving efficiency and
reducing energy use of existing buildings;
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reducing the average size of new dwellings;
introducing progressive property taxes; and
mandating net zero energy certifications.
In cities: urban planning to enable
15-minute urban centres requiring little
motorized travel and sufficiently compact
to encourage reasonable-sized dwellings;
and reallocation of some public urban
space from parking structures and roads to
infrastructure for non-motorized mobility.
Interventions such as these would make
it possible to achieve rapid decarbonization
consistent with the Paris Agreement goals,
without relying so heavily on negative
emissions technologies and productivity
improvements25. A recent study modelling
some of these interventions, with equitable
access to the energy services required for
decent living, brings global final energy
demand to as low as 150 EJ, well below the
LED and other IPCC scenarios6.
Finally, it is important to take global
justice considerations into account. Existing
climate scenarios maintain a significant
disparity in per capita energy use between
the Global North and Global South26,27.
There is some relative convergence in
certain scenarios, but none assume an
absolute convergence. This approach is
morally problematic, politically untenable
(why should Global South negotiators
accept such scenarios?), and potentially
inconsistent with human development
objectives. Instead, we should explore
convergence scenarios, reducing excess
throughput in the Global North and
increasing necessary throughput in the
Global South so that energy and resource
use converge at per capita levels that are
consistent with universal human welfare and
ecological stability.
Post-growth mitigation scenarios
All climate mitigation scenarios envision
plausible but not-yet-realized future
transformations. We hold that socially and
politically ambitious post-growth scenarios
merit equal consideration to technologically
ambitious scenarios, and should be included
alongside them28. Given the enormous
challenge of confronting the climate crisis,
and following the precautionary principle,
modellers should consider a wider range
of policy options in order to expand the
public debate about climate mitigation,
and to reflect the plurality of visions for a
sustainable world.
This requires diversifying the frameworks
used in modelling experiments. The
narratives of the Shared Socioeconomic
Pathways (SSPs) assume that even
moderately slower rates of economic growth
(such as in SSP3 and SSP4) are associated
with deepening inequalities, regional
rivalries and less technological innovation,
therefore increasing the challenges
of mitigation29. But the literature in
post-growth economics shows that it doesn’t
have to be this way; high-income nations
can maintain economic stability, invest
in innovation and achieve strong social
outcomes without the need for additional
growth, thereby making mitigation easier
to achieve7,30,31.
The SSPs and Integrated Assessment
Models should be updated, or new ones
created, to incorporate frameworks
developed by research in social metabolism,
industrial ecology32 and ecological
economics7, so that post-growth scenarios
can be successfully modelled. Such
alternative frameworks would illuminate
new possibilities and help broaden the range
of policy options for public debate. ❐
Jason Hickel1,2 ✉ , Paul Brockway 3,
Giorgos Kallis4, Lorenz Keyßer 5,
Manfred Lenzen 6, Aljoša Slameršak 2,
Julia Steinberger7 and Diana Ürge-Vorsatz8
1International Inequalities Institute, London School
of Economics, London, UK. 2ICTA, Autonomous
University of Barcelona, Barcelona, Spain. 3School of
Earth and Environment, University of Leeds, Leeds,
UK. 4ICREA and ICTA, Autonomous University
of Barcelona, Barcelona, Spain. 5Institute for
Environmental Decisions, D-USYS, ETH Zürich,
Zürich, Switzerland. 6ISA, School of Physics,
University of Sydney, Sydney, Australia. 7Institute
of Geography and Sustainability, University of
Lausanne, Lausanne, Switzerland. 8Department of
Environmental Sciences and Policy, Central European
University, Budapest, Hungary.
✉e-mail: j.e.hickel@lse.ac.uk
Published: xx xx xxxx
https://doi.org/10.1038/s41560-021-00884-9
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Acknowledgements
G.K. and A.S. acknowledge the financial support
of the Spanish Ministry of Science, Innovation and
Universities, through the ‘Maria de Maeztu’ programme
for Units of Excellence (CEX2019-000940-M).
P.B.’s time was funded by the UK Research and Innovation
Council, supported under EPSRC Fellowship award
EP/R024254/1.
Competing interests
The authors declare no competing interests.
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