Download From Acid Rain to Climate Change

POLICYFORUM
ATMOSPHERIC SCIENCE
From Acid Rain to Climate Change
Updated air pollution science and policies
address human health, ecosystem effects, and
climate change in Europe.
S. Reis,1* P. Grennfelt,2 Z. Klimont,3 M. Amann,3 H. ApSimon,4 J.-P. Hettelingh,5 M. Holland,6
A.-C. LeGall,7 R. Maas,5 M. Posch,5 T. Spranger,8 M. A. Sutton,1 M. Williams9
Substantial emissions reductions have been
achieved under CLRTAP (see the chart). Air
quality has improved, and deposition of acidifying (fig. S1) and eutrophying (fig. S2) compounds in excess of critical loads (2, 3) has
been widely reduced. The largest reductions
can be seen for sulfur dioxide: Since 1990,
several European countries have reduced
emissions by close to 80%. Sulfur deposition, once the main cause of the acidification
of lakes and soils, has markedly diminished.
Although emission reductions were, to a large
extent, achieved by cost-effective measures
proposed by science, they were also helped by
autonomous developments, such as the transition of Eastern European economies (4).
Much of the success of CLRTAP in integrating science and policy is because scientific results, assessments, and technological
solutions form an integral part of the agendas of negotiating meetings. Such meetings
typically start with an update of the available
1
Centre for Ecology & Hydrology, Penicuik EH26 0QB, UK.
Swedish Environmental Research Institute, SE-400 14
Gothenburg, Sweden. 3International Institute for Applied Systems Analysis, A-2361 Laxenburg, Austria. 4Imperial College
London, London SW7 2AZ, UK. 5National Institute for Public
Health and the Environment, Bilthoven 3721 MA, Netherlands. 6Ecometrics Research and Consulting, Reading RG8
7PW, UK. 7National Institute for Industrial Environment and
Risks, F-60550 Verneuil en Halatte, France. 8Federal Ministry for the Environment, Nature Conservation and Nuclear
Safety, D-11055 Berlin, Germany. 9Environmental Research
Group, King’s College London, London SE1 9NH UK.
2
*Author for correspondence. E-mail: [email protected]
0
SO2
NOx
NMVOC
NH3
PM2.5
–10
–20
–30
–40
–50
–60
–70
–80
–90
–100
Actual 2010
GP-2010 commitment
GP-2020 commitment
Emission reductions and commitments for 2020
under the revised GP. These commitments enter
into force upon ratification of the revised protocol
by each signatory. All percentage changes are relative to 1990 emissions. Targets of the original GP for
2010 are also shown. GP commitments for nonmethane volatile organic compounds (NMVOCs) for 2020
are above actual emissions for 2010, which were low
because of the economic situation in Europe and the
related reduction in industrial output and construction. See table S2 for details.
focus was on understanding the causes and
effects of the problem and its transboundary
nature. A basic building block was quantifying the relations between sources of emissions and pollutant concentrations and/or
deposition across Europe, with the aid of
atmospheric dispersion models. These relations demonstrated clearly that air pollution
was a problem that needed to be addressed at
a continental scale.
Further achievements of CLRTAP were
the development and consistent application
of the critical loads concept, as well as integrated assessment modeling, through which
environmental objectives were used to calculate an economically efficient distribution of
effort between countries. The science-policy
dialogue became intense in the 1990s, in particular through the Task Force on Integrated
Assessment Modelling (TFIAM) and the
Working Group on Strategies and Review
(WGSR). It was the science that convinced
policy-makers that a focus on individual pollutants was leading to suboptimal solutions
and that a multipollutant, multieffect approach
would be more cost-effective.
The GP, which entered into force in 2005,
marked a new approach, scientifically supported and economically justified. Compared
with previous international commitments on
improving air quality, which contained flat
rate reductions for separate pollutants, this
effects-based approach identified an optimal allocation of targets among countries to
reduce several damaging pollutants simultaneously, leading to considerably lower costs.
Each country agreed on emission ceilings to
be met for the key pollutants, while retaining some flexibility in how these were to be
attained (5). The GP, with its target year 2010,
has formed the basis for both international
(e.g., European Union) and national policies.
Most countries have been able to fulfill commitments in terms of emission reductions with
corresponding improvements in air quality.
Revising the GP
The Parties to the Protocol agreed to substantive amendments to the GP in May 2012 (6).
For the first time in a multilateral environmental agreement, specific account was taken of
the adverse effects of particulate matter (PM)
on health. The revision includes commitments
for emission reductions of primary particles
with an aerodynamic diameter of <2.5 µm
(PM2.5). Also, the revised GP reflects links
between regional air pollution and global climate change by including black carbon (BC).
Like tropospheric ozone, which was already
covered by the original GP, BC is a short-lived
climate-forcing pollutant (7). The amendments also include commitments to further
reduce by 2020 emissions originally covered
by the GP (sulfur dioxide, nitrogen oxides,
ammonia, and volatile organic compounds)
and to maintain these reductions thereafter.
Russia, Belarus, Canada, and other coun-
www.sciencemag.org SCIENCE VOL 338 30 NOVEMBER 2012
Published by AAAS
Downloaded from www.sciencemag.org on May 17, 2013
Policy Lessons from CLRTAP
science and end with further requests to scientists. Scientists are present in negotiation
meetings, and policy-makers participate in
scientific meetings and thus can make sure
that the science remains focused on the needs
of the policy process.
Science played a major role in establishing CLRTAP, substantiated through the
European Monitoring and Evaluation Programme (EMEP) and the Working Group on
Effects (WGE). In the early stages, the main
% change relative to 1990 emissions
T
he Convention on Long-Range Transboundary Air Pollution (CLRTAP)
under the United Nations Economic
Commission for Europe (UNECE) was established in 1979 to control damage to ecosystems and cultural heritage from acid rain, initially in Europe (1). Extended by eight protocols, most recently the Gothenburg Protocol (GP) signed in 1999, it has been key for
developing cross-border air pollution control
strategies over the UNECE region, which
includes the United States and Canada. We
describe how recent amendments to the GP
reflect improved scientific knowledge on
pollution, environmental relations, and links
between regional air pollution and global climate change.
1153
tries that are not parties to the original GP participated in negotiating the amendments. The
text opens avenues for these and other countries to accede to the GP, which increases the
spatial coverage of agreed emission-abatement measures and the political weight of the
CLRTAP. Wider coverage will also facilitate
scientific development and capacity-building
by integrating countries with limited experience in the design and implementation of
emission control policies into an established
science-policy framework.
Scientific findings have shaped and
informed policy revisions by, for example,
assessments of relations between air pollution
abatement and impacts on human health and
the environment. Illustrations of environmental impacts of different policy scenarios using
new indicators (e.g., updated critical levels
and loads, or economic impacts from ozone
on crops) have influenced explicit inclusion of
PM to reduce health effects. Inevitably, financial and political realities constrained negotiations with respect to scientific objectives.
However, integration of science and policy
into an accepted model that assesses technological, economical, ecological, and public
health issues enabled new countries to agree
on emission reductions, even in times of economic austerity.
Parties revised their “baselines” after
recent changes in economic projections; thus,
most parties’ commitments to the revised
protocol fall short of the reductions previously projected for the year 2020 (8) that were
intended to take into account current legislation and policies on energy and environment already in the pipeline. The revised GP
does not include mandatory abatement measures for small combustion installations and
mobile machinery nor additional mandatory
measures reducing ammonia emissions from
agriculture. Despite the limited ambitions in
the GP amendments, substantial improvements in air quality are expected over coming
years. Yet, these measures will not be enough
to meet air-quality targets, such as critical
loads and World Health Organization guidelines, to protect the environment and public
health. Although the agreed emission levels
imply that by 2020 only 4% of European ecosystems will be at risk of acidification, 42% of
European terrestrial ecosystems will remain
at risk from nitrogen eutrophication and consequent biodiversity loss (9) (figs. S1 and S2
and table S1). The average loss in human life
expectancy attributable to exposure to fine
PM will decline from 7.4 months in 2005 to
4.4 months in 2020 (8).
Even if hemispheric background concentrations of ozone have increased, control
1154
of ozone precursor emissions according to
amended GP targets is expected to further
reduce peak ozone concentrations and their
effects on human health and agriculture.
The loss in wheat production due to ozone is
expected to decrease from 27 million metric tons in 2000 to 16.5 million metric tons
in 2020 (4), corresponding to a total value
of €1.96 billion (U.S. $2.49 billion) saved.
Despite this, effects of ozone on food security and carbon sequestration will remain an
issue (10).
Challenges After the GP Revision
After the GP revision, CLRTAP faces additional challenges. The parties recently agreed
on a long-term strategy (11), emphasizing
scientific guidance and further development
based on minimizing adverse environmental
and health effects most efficiently. It further
emphasizes how CLRTAP must assess multiple interactions of air pollution effects in relation to climate change, health, and biodiversity. Although economic assessment of costs
and benefits has long been performed under
CLRTAP (12), recognition of the scale and
variety of benefits to society from environmental improvements under CLRTAP needs
to be factored into policy-making.
Air and climate cannot be tackled independently of each other; nevertheless, linking air
pollution and climate change policies more
closely remains a challenge. This includes
short-lived climate forcing and environmental effects of BC and tropospheric ozone (13)
and the effect of nitrous oxide on stratospheric
ozone depletion (14).
Another challenge is to account for intercontinental transport of atmospheric pollutants, for more cost-effective policy options.
Both increased hemispheric background levels of ozone and transport of many persistent
organic compounds and mercury between
continents and into the Arctic have been
thoroughly investigated (15). These problems need activities both within and outside
CLRTAP. CLRTAP promotes collaborative
efforts on a multiregional or global scale, such
as through the Task Force on Hemispheric
Air Pollution, in which many Asian scientists
are involved, the UN Environment Program
(UNEP), and the Global Air Pollution Forum.
The European Nitrogen Assessment (16)
established that an integrated approach to
manage nitrogen fluxes and control emissions is lacking. Because much of the problem is related to atmospheric emissions, the
CLRTAP requested its Task Force on Reactive Nitrogen to develop an integrated policy
approach for nitrogen. Inclusion of national
nitrogen budgets in the amendments to
the GP is a step in that direction, and the
Task Force is developing partnerships with
UNEP and the Organization for Economic
Cooperation and Development, as well as
the biodiversity and water conventions, on
improving nitrogen use efficiency.
Close collaboration and interaction of science with policy plays an important role in the
CLRTAP. In this regard, it differs from the UN
Framework Convention on Climate Change,
as the science-policy interface under the CLRTAP is embedded in its organizational structure (17). The organization of scientific bodies (EMEP, WGE, and their subsidiary bodies) within CLRTAP, as well as the work done
bridging science and policy within the TFIAM
and the WGSR, make the CLRTAP a unique
model worth wider consideration within different international policy forums.
References and Notes
1. UNECE, Clearing the Air (UNECE, Geneva, 2009); http://
www.unece.org/fileadmin/DAM/env/lrtap/Publications/
ECE_Clear_Air_WEB_30th_anniversary_brochure.pdf.
2. J.-P. Hettelingh et al., Water Air Soil Pollut. Focus 7, 379
(2007).
3. A critical load is a quantitative estimate of an exposure to
one or more pollutants below which major harmful effects
on specified elements of the environment do not occur.
4. P. Rafaj, M. Amann, J. Cofala, R. Sander, Factors determining recent changes of emissions of air pollutants in Europe:
Service Contract on Monitoring and Assessment of Sectorial
Implementation Actions (ENV.C.3/SER/2011/0009, IIASA,
Laxenburg, Austria, 2012).
5. G. Sundqvist, in Governing the Air: The Dynamics of
Science, Policy, and Citizen Interaction, R. Lidskog and
G. Sundqvist, Eds. (MIT Press, Cambridge, MA, 2011),
pp. 195–221.
6. UNECE, Parties to UNECE Air Pollution Convention approve
new emission reduction commitments for main air pollutants by 2020 (UNECE, Geneva, 2012); http://www.unece.
org/index.php?id=29858.
7. UNEP, Near-term climate protection and clean air benefits: actions for controlling short-lived climate forcers
(UNEP Synthesis Report, UNEP, Nairobi, 2011); http://
www.unep.org/pdf/Near_Term_Climate_Protection_&_
Air_Benefits.pdf.
8. M. Amann et al., Environ. Model. Softw. 26, 1489 (2011).
9. M. Posch, J. Aherne, J.-P. Hettelingh, Environ. Pollut. 159,
2223 (2011).
10. G. Mills, H. Harmens, Ozone Pollution: A hidden threat to
food security (ICP Vegetation, Bangor, Wales, 2011); http://
icpvegetation.ceh.ac.uk/publications/thematic.html.
11. Decision 2010/18, Long-term strategy for the Convention
on Long-Range Transboundary Air Pollution and action plan
for its implementation; www.unece.org/env/lrtap/executivebody/eb_decision.html.
12. M. Holland et al., Cost-benefit analysis for the revision of
the national emission ceilings directive (AEA, Didcot, UK,
2011); http://ec.europa.eu/environment/air/pollutants/pdf/
Gothenburg%20CBA1%20final%202011.pdf.
13. D. Shindell et al., Science 335, 183 (2012).
14. A. R. Ravishankara et al., Science 326, 123 (2009).
15. F. Dentener, T. Keating, H. Akimoto, Eds., Hemispheric
transport of air pollution 2010 (Air Pollution Studies no.
17-20, ECE/EB.AIR/100-103, United Nations, New York,
2010); www.htap.org/publications/assessment_reports.htm.
16. M. A. Sutton et al., Eds., The European Nitrogen Assessment
(Cambridge Univ. Press, Cambridge, 2011).
17. F. Raes, R. Swart, Science 318, 1386 (2007).
Supplementary Materials
www.sciencemag.org/cgi/content/full/338/6111/1153/DC1
30 NOVEMBER 2012 VOL 338 SCIENCE www.sciencemag.org
Published by AAAS
10.1126/science.1226514
Downloaded from www.sciencemag.org on May 17, 2013
POLICYFORUM