evolution of ozone depleting substances in the australian … · nature, 1974 stratospheric sink...

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

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

www.cawcr.gov.au

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



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


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



1978: Cape Grim joins the NASA-funded

AGAGE network



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]

http://en.wikipedia.org/wiki/File:MIT_Seal.svg

//upload.wikimedia.org/wikipedia/commons/e/e5/NASA_logo.svg

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



Three key elements underpinning Australian

ODS research



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 The Centre for Australian Weather and Climate Research


methyl chloroform at Cape Grim



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



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


‘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



Column O3 at Halley, Antarctica, & Melbourne, Australia



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



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



Dedication: F. Sherwood ‘Sherry’ Rowland:

1927 - 2012



‘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

//upload.wikimedia.org/wikipedia/en/a/a5/UC_Irvine_Seal.png

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

Thank you www.cawcr.gov.au

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

evolution of ozone depleting substances in the australian … · nature, 1974 stratospheric sink...

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