Importance of the Montreal Protocol for ozone layer and climate

1
Importance of the Montreal Protocol for ozone
layer and climate

• Guus Velders, The Netherlands

WMO/UNEP Ozone Research Managers Geneva, May 19,
2008
2
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)
3
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)
4
Montreal Protocol provided dual protectionto
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 4,000 11,000
• - HCFCs 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 1980-levels around
  2050
• Polar region EESC back to 1980-levels 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

• 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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Thank you foryour attention
Study in close collaboration withStephen
Andersen (EPA)John Daniel
(NOAA)David Fahey (NOAA)Mack
McFarland (DuPont)