Importance of the Montreal Protocol for ozone layer and climate

Guus Velders, The Netherlands

WMO/UNEP Ozone Research Managers

Geneva, May 19, 2008

Guus Velders, Montreal Protocol and Climate 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)

Guus Velders, Montreal Protocol and Climate 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)

Guus Velders, Montreal Protocol and Climate 4

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: 4,000 – 11,000

- HCFCs: 700 – 2,300

Guus Velders, Montreal Protocol and Climate 5

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

Guus Velders, Montreal Protocol and Climate 6

Production scenarios

Baseline:- current Montreal Protocol- in agreement with observations- used in WMO (2007)

Without 1974 paper

Molina and Rowland:

3-7% annual growth

Without 1987

Montreal Protocol:

2-3% annual growth

Guus Velders, Montreal Protocol and Climate 7

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

Guus Velders, Montreal Protocol and Climate 8

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

Guus Velders, Montreal Protocol and Climate 9

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

Guus Velders, Montreal Protocol and Climate 10

Effects on climate

World avoided by the Montreal Protocol

Reduction Montreal Protocol of ~11 GtCO2-eq/yr

5-6 times Kyoto target

(incl. offsets: HFCs, ozone depl.)

CO2 emissions

Velders et al., PNAS, 2007

Guus Velders, Montreal Protocol and Climate 11

Radiative forcing leading to climate change

Reduction in radiative forcing of

~0.23 Wm-2 in 2010

about 13% of CO2 emissions

of human activities

Velders et al., PNAS, 2007

Forcing: delay of ~10 years cf CO2 emissions

10 years

Guus Velders, Montreal Protocol and Climate 12

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

Guus Velders, Montreal Protocol and Climate 13

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

Guus Velders, Montreal Protocol and Climate 14

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

Guus Velders, Montreal Protocol and Climate 15

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)

Guus Velders, Montreal Protocol and Climate 17

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

Guus Velders, Montreal Protocol and Climate 18

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

Guus Velders, Montreal Protocol and Climate 19

Thank you foryour attention

Study in close collaboration with:

Stephen Andersen (EPA)John Daniel (NOAA)David Fahey (NOAA)Mack McFarland (DuPont)