Download The importance of the Montreal protocol in protecting climate

Guus Velders, The Netherlands
Importance of the
Montreal Protocol
for ozone layer and
climate
WMO/UNEP Ozone Research Managers
Geneva, May 19, 2008
Well known benefits Montreal Protocol
Large decreases in CFC
production (90%) and
emissions (60-90%)
Concentrations also decreasing
Increases for HCFCs and HFCs
WMO (2007)
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Well known benefits Montreal Protocol (2)
• Emerging evidence of start of
ozone layer recovery
• Full recovery around 2050
• Polar regions 10-25 years later
• Recovery can be affected by:
– Future production CFCs, HCFCs
– Production methyl bromide
– Emissions from existing
equipment
– Interaction with climate change
WMO (2007)
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Montreal Protocol provided dual protection:
to Ozone layer and to Climate change
 Climate benefits already achieved larger than Kyoto
Protocol targets for 2008-2012
 Potential for additional climate benefits significant
compared to Kyoto
Reason: CFCs, HCFCs are greenhouse gases  Large
GWPs: - CO2 :
1
- CFCs:
- HCFCs:
4,000 – 11,000
700 –
2,300
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Decrease in production of CFCs
• 1974: Molina and Rowland: CFCs
affect the ozone layer
- Public concern  drop production
• ~1980: Increase in production:
- New applications
- Growth in Asia and Europe
• 1987: Montreal Protocol:
- Restricting prod/use CFCs, halons
• 2010: Global production stop CFC
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Production scenarios
Without 1974 paper
Molina and Rowland:
3-7% annual growth
Without 1987
Montreal Protocol:
2-3% annual growth
Baseline:
- current Montreal Protocol
- in agreement with observations
- used in WMO (2007)
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Concentration scenarios
• Delays compared to prod/emis.
due to long lifetimes
• Exponential growth without early
warning in 1974
• Continued growth without
Montreal Protocol
Velders et al., PNAS, 2007
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Effect on ozone layer
• Mid-latitude: EESC back to 1980levels around 2050
• Polar region: EESC back to 1980levels around 2065:
– Older age of air in polar vortex
• Large ozone depletion without
Montreal Protocol and
amendments
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Ozone layer recovery
• Largest potential reductions:
– Destruction of banks of CFCs
– Destruction of banks of halons
– Limiting future production of HCFCs
• Interaction with climate change:
– Cooling upper stratosphere  ozone increase
– Cooling lower stratosphere  more activation on PSC 
ozone destruction
– Circulation changes
 Overall effect uncertain
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Effects on climate
CO2 emissions
World avoided by the
Montreal Protocol
Reduction Montreal Protocol of
~11 GtCO2-eq/yr
5-6 times Kyoto target
(incl. offsets: HFCs, ozone depl.)
Velders et al., PNAS, 2007
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Radiative forcing leading to climate change
Forcing: delay of ~10 years cf
CO2 emissions
10 years
Reduction in radiative forcing of
~0.23 Wm-2 in 2010
about 13% of CO2 emissions
of human activities
Velders et al., PNAS, 2007
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Ozone-depleting substances not in Kyoto
Total target Kyoto: about 2 GtCO2-eq/yr
• CFCs not included in Kyoto Protocol
–
–
–
–
Already covered and soon to be phased out
Benefits for polluting countries
Separate protocols
Negative offset potentially large
• With Montreal Protocol, CFCs likely included in Kyoto
Protocol, but:
– Effects at least 10 years later
– Starting at much higher baseline
– Harder to eliminate
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Offsetting the climate benefits
• About 80% of ozone depleting-substances replaced by
non-fluorocarbons
• Substitute gases for CFCs
– HFCs and HCFCs
– HFC emissions: 0.9 GtCO2-eq/yr by 2010 (IPCC)
• Negative radiative forcing of ozone depletion
– IPCC estimate of -0.05 +/- 0.05 W/m2 for 1979-2005
• Total offsets about 30% of direct forcing
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Montreal 2007 adjustment: HCFC phase-out
September 21, 2007 in Montreal:
• Adjustment of Montreal Protocol: accelerated HCFC phase-out
• Climate effects taken into account
• Developed countries:
– Phase-out from 2030  2020 (+ intermediate reductions targets)
• Developing countries:
– Freeze in 2012
– Phase-out from 2040  2030 (+ intermediate reductions targets)
– Base level from 2015  average 2009-2010
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Montreal 2007 adjustment: HCFC phase-out
Recovery ozone layer ~3 years
earlier
Reduction in emissions:
• 7-9 Mtonnes HCFCs
• 0.35-0.45 MtCFC-11-eq
• 12-15 GtCO2-eq  ~100 million
cars per year
• Effects depend on alternatives
being used
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Possible additional benefits
• Better containment in
refrigeration
• Destruction of ODS banks
• Alternatives with lower GWPs
• Potential reductions:
(by 2015 in GtCO2-eq/yr)
– CFCs:
0.12
– HCFCs: partly done
– HFC-23: 0.30 (by-product)
– HFCs:
0.44 (alternative
.
chemicals)
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Conclusions
Montreal Protocol provided dual protection:
to Ozone layer and to Climate change
• Already achieved climate benefits 5-6 times larger than
Kyoto Protocol targets for 2008-2012
• Montreal Protocol: delay in CO2-forcing of ~10 years
• Montreal 2007 adjustment:
– Emissions reduced by 12-15 GtCO2-eq (depends on replacements)
– Ozone layer recovery ~3 years earlier
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Conclusions (2)
• Potential for additional climate benefits significant
compared to Kyoto Protocol targets (2008-2012):
– Better containment in refrigeration
– Destruction of CFCs, HCFC in exiting refrigerators, foams
– Alternatives with lower GWPs
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Study in close collaboration
with:
Stephen Andersen
John Daniel
David Fahey
Mack McFarland
(EPA)
(NOAA)
(NOAA)
(DuPont)
Thank you for
your attention
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