Download Short-Lived Climate Pollutants

Short-Lived Climate Pollutants - scientific background
Peringe Grennfelt
IVL Swedish Environmental Research Institute
Background
§  Air pollution and Climate are strongly connected
–  Co benefits in control were identified several years ago
and considered in the EU thematic strategy for air
pollution in 2005
–  Energy efficiency, fuel switch - Coal (oil) to natural gas etc.
–  Some trade-offs also
–  Replacing fossil fuels with bioenergy may increase PM emissions
–  Climate change may influence air pollution dispersion
and effects
–  Atmospheric pollutants may influence the global
radiation balance
[Title]
[Lecturer], [Date]
Atmospheric pollutants of concern
§  Particles
–  Black carbon and other sunlight absorbing compounds
–  Sulphates and other sunlight reflecting compounds
§  Gases
–  Methane
–  Tropospheric ozone
–  HFCs
(not an atmospheric
pollutant)
Sunlight
CH4
CO
VOC
O3
NOx
[Title]
[Lecturer], [Date]
A word about lifetimes
§  Black carbon typically less than 1 week
§  Ozone: typically 15-30 days
§  Methane: 12 years (some recent studies 8-10 years)
§  The short lifetime means that the climate effect
primarily will occur over a shorter time period than for
carbon dioxide.
[Title]
[Lecturer], [Date]
[Title]
[Lecturer], [Date]
Air pollution policies
§  Strong focus on reducing health effects from
–  Particles, in particular black carbon. The recently (May
2012) revised Gothenburg Protocol under CLRTAP is for
the first time including control of primary particles and it
put particular emphasis to black carbon.
–  Particles will probably be further considered in the
revision of the EU thematic strategy (will probably
highlight both the climate and health effect)
–  Ozone (health and vegetation damages). For vegetation
a recent study indicates a crop loss of 15-20% for wheat
for EU27 to a value of 3.2 bn € (2000).
[Title]
[Lecturer], [Date]
Ozone
Ozone is of concern for food security
NAT2020
NAT2000
Ozone impact
on wheat
production
Wheat
2000
2020
Total production
133 MT
Production loss
27 MT
16 MT
economic value
loss
3.2 b€
2.0 b€
The magnitude of the impact is reduced
The areas (intensely) impacted are
reduced
The impact occurs on 85% of EMEP
grid cells
[Title]
[Lecturer], [Date]
So to the role of SLCPs in the climate
system
§  First and most important:
§  Control of SLCPs should not be seen as an alternative to
control the long-lived climate gases but
§  It offers a possibility of achieving an additional control
of the global warming over the next decades.
[Title]
[Lecturer], [Date]
UNEP-BC/O3 Report &Science Paper
Shindell et al, 2012
The idea behind
SLCP policies
0.50C Reduction by 2050
BC+Methane+Ozone
§  A fast reduction in
emissions of black
carbon and methane
may give substantial
climate benefits over
the next 20-40 years
[Title]
[Lecturer], [Date]
The residence time is important for the
climate effect
§  CO2 and other long-lived greenhouse gases are evenly
distributed and the radiation effect (radiative forcing) is
thus global
§  For methane it is also in reality global even if there are
some differences in concentrations between the N and
the S hemisphere
§  For ozone, there are some regionality. Most of the
global increase in tropospheric ozone occurs in the N
hemisphere.
§  For black carbon the area of radiative forcing is strongly
dependent on atmospheric circulation patterns
[Title]
[Lecturer], [Date]
The region where the emissions occur matters
Region of radiative forcing
Source region
Region of radiative response
[Title]
[Lecturer], [Date]
Ozone has also an indirect effect
through reducing carbon sequestration
§  Reduced photosynthesis and annual uptake in the green
biomass
§  Decreased long term sequestration in wood and soils.
The indirect effect is of the same order as the direct
effect. This effect is not considered in connection with
SLCP policies
[Title]
[Lecturer], [Date]
§  We have an overall understanding of the importance of
the SLCPs but we still need more research and refined
models to make quantitative estimates of the regional
effects.
§  International collaboration on science is going on in
several organisations, e.g.
–  IPCC
–  CLRTAP
–  EU-projects
[Title]
[Lecturer], [Date]
SLCPs within the Convention on Long
Range Transboundary Air Pollution
(CLRTAP)
§  Was brought up at a conferences in Gothenburg in 2007
and 2009.
§  The Convention initiated a one year study during 2010
§  From 2011 and onwards the scientific background for
further work on SLCPs will be organised under The Task
Force on Hemispheric Transport of Air Pollution
(TFHTAP),
§  The TFHTAP (initiated in 2004) has the objective to
form science-based inputs to the Convention on
intercontinental transport of air pollution
[Title]
[Lecturer], [Date]
TF HTAP’s Mandate
§  In 2010, the Executive Body of the Convention renewed the mandate
for TF HTAP to:
– Examine the transport of air pollution, including ozone and its
precursors and particulate matter and its components (including
black carbon), across the Northern Hemisphere
– Assess potential emission mitigation options available inside and
outside the UNECE region
– Assess their impacts on regional and global air quality, public
health, ecosystems, and near-term climate change in collaboration
with other groups both inside and outside the Convention.
[Title]
[Lecturer], [Date]
Conclusions
§  Several interlinks between climate and air pollution
§  Black carbon, methane and ozone contribute
significantly to global warming as well as to large
effects on human health and the environment.
§  Sulphur dioxide on the contrary has a cooling effect but
still reductions are necessary due to health and
environmental effects
§  Significant measures are taken in some parts of the
world to reduce the effects of these pollutants.
§  Necessary to consider both the climate and health/
environment aspects in the future
[Title]
[Lecturer], [Date]
Thank you
[Title]
[Lecturer], [Date]