Evolution of Ozone Depleting Substances in the Australian Atmosphere - - PowerPoint PPT Presentation

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Evolution of Ozone Depleting Substances in the Australian Atmosphere

Presented at: A Silver Lining: Celebrating 25 Years of the Montreal Protocol The Australian Academy of Science Canberra, 13 September 2012

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Paul Fraser FTSE

CSIRO Marine and Atmospheric Research, Aspendale

What are ‘Ozone Depleting Substances – ODSs’?

• In the context of the Montreal Protocol, an ODS is any chemical containing chlorine (Cl) and/or

bromine (Br), after release into the lower atmosphere, can be transported to the stratosphere, where it breaks down releasing reactive Cl and/or Br that can significantly destroy stratospheric O3

• There are more than 100 ODSs identified for regulation under the Montreal Protocol – an

international agreement designed to protect the stratospheric ozone layer (O3) by controlling ODS production and consumption

• examples:
• CFCs (CFC-12: CCl2F2) - refrigerant
• HCFCs (HCFC-22: CHClF2) - refrigerant
• halons (H-1211: CBrClF2 - fire-fighting agent

The Centre for Australian Weather and Climate Research A partnership between CSIRO and the Bureau of Meteorology

Nature, 1974

Stratospheric sink for chlorofluoromethanes: chlorine atom-catalysed destruction of ozone

• M. J. Molina & F. S. Rowland

Department of Chemistry, University of California at Irvine

• ‘Chlorofluoromethanes are being added to the environment in steadily increasing amounts. These

compounds are chemically inert and may remain in the atmosphere for 40–150 years, and concentrations can be expected to reach 10 to 30 times present levels. Photodissociation of the chlorofluoromethanes in the stratosphere produces significant amounts of chlorine atoms, and leads to the destruction of atmospheric ozone’

• CSIRO job interview:

‘What chemicals might be important to measure in the atmosphere?’

• Answer:

‘CFCs – they might destroy the Earth’s ozone layer’

• 1995 Nobel Prize for Chemistry

The Centre for Australian Weather and Climate Research

A partnership between CSIRO and the Bureau of Meteorology

Where did it all begin?

1974: wrote to Jim Lovelock

• 1973

‘CFCs in and over the North and South Atlantic’, Lovelock et al., Nature

• Question:

‘How do I measure CFCs in the atmosphere?’

• Answer:

‘GC-ECD – I will visit your laboratory in Australia and teach you’

• June 1975:

Lovelock & Fraser made the first CFC-11, CH3CCl3 & CCl4 measurements in the Australian atmosphere

The Centre for Australian Weather and Climate Research A partnership between CSIRO and the Bureau of Meteorology

• Professor James Lovelock FRS
• 1969 - the electron capture detector (ECD)
• 1974 - Fellow Royal Society
• 1979 - Gaia: A New Look at Life on Earth
• 1997 - Blue Planet Prize

1976: Cape Grim, Tasmania - Australia’s first GHG & ODS Monitoring Station

• caravan donated by NASA (previously used in Apollo 13 mission)
• 1976: commenced CFC-11, CH3CCl3, CCl4 measurements
• 1978: commenced collection of Cape Grim air archive
• 1978: joined AGAGE: international network of ODS monitoring and modelling laboratories

The Centre for Australian Weather and Climate Research A partnership between CSIRO and the Bureau of Meteorology

1978: Cape Grim joins the NASA-funded AGAGE network

The Centre for Australian Weather and Climate Research A partnership between CSIRO and the Bureau of Meteorology

Ragged Point, Barbados [13ºN, 59ºW] Trinidad Head, California [41º N, 124ºW] Cape Matatula, American Samoa [14ºS, 171ºW] Mace Head, Ireland [53ºN, 10ºW] Cape Grim, Tasmania [41ºS, 145ºE]

Cape Grim ODS inventory: currently 35 species

• In situ measurement program: 12 times per day, 365 days per year, 27 ODSs
• CFCs (6):

CFC-11, CFC-12, CFC-113, CFC-114, CFC-115, CFC-13

• HCFCs (5): HCFC-22, HCFC-141b, HCFC-142b, HCFC-123, HCFC-124
• Halons (3): H-1211, H-1301, H-2402
• chloromethanes (4): carbon tetrachloride, methyl chloride, dichloromethane, chloroform
• bromomethanes (5): methyl bromide, dibromomethane, bromoform, bromodichloromethane, bromochloromethane
• haloethanes, ethenes, propanes (4): methylchloroform, trichlorethylene, perchloroethylene, n-propylbromide
• In addition, measured in the Cape Grim Air Archive, 7 ODSs
• CFCs (4):

CFC-112, CFC-112a, CFC-113a, CFC-114a

• HCFCs (2): HCFC-21, HCFC-133a
• Halons (1): H-1202
• ODSs (16) in red are used internationally to define equivalent stratospheric chlorine
• predictions of future O3 levels depend on estimates of future emissions of these 16 ODSs

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Three key elements underpinning Australian ODS research

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Cape Grim, Tasmania [41°S, 144°E] Cape Grim air archive: 1978-2011

Law Dome South Pole

CFC-12 at Cape Grim

 refrigerant – atmospheric lifetime 120 years  the major source of stratospheric Cl for decades to come  85% decline in emissions: small remaining use and emissions from ‘banks’  no natural CFC sources

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methyl chloroform at Cape Grim

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 degreasing solvent (metal surface cleaning) - atmospheric lifetime 5 years  emissions close to zero: 99% decline, almost completely removed from the atmosphere  a major cause of the decline in total Cl since the mid-1990s

Methyl bromide at Cape Grim

 natural background level: 5-6 ppt maintained by emissions from the oceans  agricultural, structural and quarantine fumigant  agricultural and structural emissions controlled by Montreal Protocol – rapid decline  most ‘above background’ CH3Br now due to quarantine uses

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HCFC-141b at Cape Grim

 used in commercial refrigerant blends: 2 phase emissions  baseline data and local pollution episodes shown  baseline data → global emissions  pollution data → local (SE Australian/Australian) emissions

The Centre for Australian Weather and Climate Research A partnership between CSIRO and the Bureau of Meteorology

‘Stratospheric chlorine’: past and future

 20% from natural sources: CH3Cl, CH3Br  80% industry/agriculture: CFCs, halons,

CH3Br etc.

 fallen 8% since peak in mid-1990s  future dominated by CFCs already present in

the atmosphere

 return to 1980 levels by 2050

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Column O3 at Halley, Antarctica, & Melbourne, Australia

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• strong correlation between stratospheric ‘chlorine’ and total ozone
• ozone recovery has commenced above Antarctica and at mid-latitudes

Global & Australian ODS emissions from atmospheric data

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• global peak: 9000 M tonnes CO2-e; Australian peak ~40 M tonnes (0.5% of global)
• Australian ODS emissions decline since 1990: 30 M tonnes CO2-e (5% of total Australian GHG emissions)
• equivalent to taking 300,000 cars off the road
• Australian CO2-e changes (1990-2010) → CO2: 125 Mt; CH4: -5 Mt; N2O: 5 Mt; HFCs/PFCs/SF6: 2 Mt
• Montreal Protocol: most successful climate change mitigation policy option adopted thus far

Australian ODS research: ……achievements

• first continuous measurements of ODSs in the Southern Hemisphere
• Cape Grim: the most important facility for measurement ODSs in the SH
• Cape Grim Air Archive, described by Megan Clark (CSIRO CEO) as a ‘national treasure’
• discovered 14 previously unidentified ODSs in atmosphere at Cape Grim:
• CFCs: CFC-13, CFC-112, CFC-112a, CFC-113a, CFC-114, CFC-114a, CFC-115
• HCFCs: HCFC-21, HCFC-123 , HCFC-133a, HCFC-141b, HCFC-142b
• halons: H-1202 , H-2402
• observation-based atmospheric history of all the important ODSs from 1930s to present
• observation-based estimate of effective stratospheric chlorine: 1930s-present
• Australian ODS data: all 7 international assessment of ozone depletion since the late-1980s
• ‘top-down’ estimate of Australian ODS emissions
• demonstrate the significant Montreal Protocol impact on reducing Australian GHG emissions

The Centre for Australian Weather and Climate Research A partnership between CSIRO and the Bureau of Meteorology

Dedication: F. Sherwood ‘Sherry’ Rowland: 1927 - 2012

The Centre for Australian Weather and Climate Research

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‘He inspired many to walk in the shadow of his greatness’

• fellow Nobel Laureate, Prof. Mario Molina, MIT, March 2012

1952: PhD, U. Chicago (W. Libby – Nobel Prize for Chemistry 1960) 1974: the Nature paper 1989: Japan Prize 1993: President AAAS 1993: Peter Debye Award (ACS) 1994: Roger Revelle Medal (AGU) 1995: Nobel Prize for Chemistry with M. Molina and P. Crutzen

The Centre for Australian Weather and Climate Research

A partnership between CSIRO and the Bureau of Meteorology

Thank you

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CSIRO/Bureau of Meteorology ODS Team Paul Fraser, Nada Derek, Bronwyn Dunse, David Etheridge, Paul Krummel, Ray Langenfelds, Paul Steele, Cathy Trudinger & the late Laurie Porter