Joëlle Gergis Climate Research Fellow, School of Earth Sciences, University of Melbourne

David Karoly, School of Earth Sciences University of Melbourne

Karl Braganza, Australian Bureau of Meteorology, Melbourne

Rob Allan, Met Office Hadley Centre, United Kingdom

Neville Nicholls, School of Geography & Enviro Science, Monash University

Chris Turney, School of Geog, Archaeology & Earth Resources, Uni of Exeter, UK

Andrew Lorrey, National Institute for Water & Atmospheric Research (NIWA)

Reconstructing south-eastern Australian temperature, rainfall & pressure using palaeo, documentary & early instrumental data

Reconstructing south-eastern Australian temperature, rainfall & pressure using palaeo, documentary & early instrumental data

Multi-proxy reconstructions of ENSO: AD1525–2002

Already developed ENSO reconstructions for A.D. 1525–2002 period using 14 palaeo-records, trying to improve western Pacific data representation:

• Gergis and Fowler (2009) Climatic Change - ENSO event analysis• Braganza et al (2009), Journal of Geophysical Research – ENSO EOF reconstructions• Fowler et al (2007), International Journal of Climatology - Kauri tree-ring reconstructions

Ice CoreTree-rings Coral Documentary

Dec 1997-98 SST anomalies NCEP/Reynolds SST reanalysis

??

South-eastern Australia’s regional climate history

- Important region to study Southern Hemisphere circulation features: ENSO is a large driver of SE Australian climate variability: but what about about SAM, IOD, STR, PDO/IOD?

e.g. ~50% DJF rain SE OZ since 1979 explained by SAM, Indonesian SSTs: IOD +ve, dry SE OZ

- Multi proxy temperature, rainfall and pressure reconstructions of Australasia are yet to be compiled: extending Turney et al’s effort to compile Australia-wide mean annual Temp

The ‘Big Dry’: SE Oz in its 12th year of drought- Since spring 1996, rainfall in SE Australia has been below average

- Since 2000, failure of autumn (MAM) ‘drought breaking’ rain to replenish water supplies

- Increasing temps (increasing evaporation) exacerbating drought

- Is SE Oz seeing the start of a similar anthropogenically-forced drying trend detected in SW since 1970s??

- Karoly and Braganza showed Australian average temp influenced by anthropogenic warming: no specific detection and attribution studies on SE Oz trends

Source: Australian Bureau of Meteorology

Is the recent drying in SE Australia extreme climate variability or unprecedented climate change?

- Can improve estimates of natural/baseline climate variability by looking at pre-C20th records provided by palaeo and historical sources

- How has temp, rainfall & pressure fluctuated over longer timescales?

- Palaeo helps place recent climate variability into a long term context

- Increasing temperatures are exacerbating drought in an already dry country

Dust storm Mildura, VIC 1940 Flood, Punt Rd, Melbourne 1891

Source: Museum Victoria Source: Fairfax Publishers

Northern Hemisphere temp reconstructions

Source: Mann et al (2008) PNAS 105 (36): 13252–13257

- A dozen ‘multi proxy’ reconstructions of NH temp or mean global temp now compiled for past 1–2Ka

- Contributes valuable information about natural climate variability to the IPCC assessment reports

- Most recent decade warmest in at least the past 1,300 years

Southern Hemisphere temp reconstructionsIPCC AR4, only 6 records used to reconstruct annual mean SH temperature change over the past 1.5 ka, only 2 from Australia

Source: Jansen et al. (2007) IPCC WG1 chapter 6

Key palaeoclimate uncertainties in IPCC AR4“Knowledge of climate variability of last 1–2 ka in the Southern

Hemisphere and tropics is severely limited by the relative lack of palaeoclimatic records” Jansen et al (2007) p483

- There are more than 6 palaeo records in the SH !

- Lack of data integration and consolidated research effort in SH??

- NOAA has a strong palaeoclimate program, still disconnected from mainstream climate science in Australia

- Major climate impacts in Australian region > target knowledge gap

Source: Fairfax Publishers

ARC Linkage 2009 proposal: multi-disciplinary research team, 10 partner organisations (submitted Nov 2008)

KEY INVESTGATORS

1. Joelle Gergis, Uni Melbourne

2. David Karoly, Uni Melbourne

3. Neville Nicholls, Monash University

4. Rob Allan Met Office Hadley Centre

5. Chris Turney, University of Exeter

6. Andrew Lorrey, NIWA

7. Don Garden, University of Melbourne

PARTNER ORGANISATIONS

1. Bureau of Meteorology (Karl Braganza)

2. UK Met Office Hadley Centre

3. Murray–Darling Basin Authority

4. VIC Depart Sustainability & Environment

5. Melbourne Water

6. National & State Libraries Australasia

7. National Library of Australia

8. State Library of NSW

9. State Library of VIC

10. Powerhouse Museum

-Temperature, rainfall and MSLP reconstructions for SE Oz using palaeo, documentary and early weather station data > palaeo addition to SEACI

- Multi-disciplinary initiative: meteorologists, water managers, palaeoclimatologists, environmental historians > policy relevant outcomes

1. Annually resolved palaeoclimate records: 200–500 yrs

CoralTree rings

SpeleothemIce core

Antarctica

As few as 3 well-dated records can capture ~40% instrumental variance (annually averaged Tmax, PDSI) over Australia (Nicholls et al., 2006; D’Arrigo et al., 2009)

A new approach to proxy reconstruction?- 57% of variance in mean annual Tmax associated with rainfall variability in Eastern Australia, 42% in South-eastern Australia

- i.e when it is hotter, it is drier > high temp and low rain ass. with high MSLP

- Opportunity for multi-variate proxy calibration and reconstruction (new approach)

Source: Gergis et al unpublished data

2. Documentary records – our early scribes

- Weather diaries/ship logbooks

- Newspapers

- Annual gazettes/almanacs

Lieutenant David CollinsGovernor Arthur Philip Captain John Hunter

- European explorer records

- Early settler accounts

- Government correspondence

Will be used to develop Australia’s first comprehensive climate history using documentary records

from first European settlement in 1788: culturally and scientifically significant: see Gergis (2008)

Colonial documents contain weather information

Source: David Collins (1796). An account of the English Colony at New South Wales

February 1791: ‘The heat was so excessive that immense numbers

of the large fox bat were seen…dropping into the water…many

dropped dead while on the wing...In several parts of the harbour the

ground was covered with different sorts of small birds, some dead,

and others gasping for water…From the numbers which fell into the

brook at Rose Hill, the water was tainted for several days…it was

supposed that more than 20 000 of them were seen within the space

of one mile’ John Hunter (1793)

June 1791: The ground was so dry, hard and literally burnt up, that

it was almost impossible to break it with a hoe; and until this time

there has been no hope or probability of the grain vegetating

David

Collins (1804)

Quantifying documentary accounts of past climate

- Assign a numerical value to these accounts (e.g. hot=1, very hot=2 extremely hot =3, etc) to create a simple time series > common practice in Europe and the Americas Source: Fairfax Publishers

Source: Royal Botanic Gardens, Sydney

- William Dawes’s weather diary for Port Jackson (Sydney)

- Australia’s first official meteorological record

- Sept 1788 to Dec 1791

- 4 to 6 times daily temperature, pressure, winds and remarks

- Data recently analysed Gergis, Karoly and Allan: now in review Australian Meteorological Magazine

Source: Powerhouse Museum

3. Early instrumental data

William Dawes’s Sydney Cove temperature record, 1788 –1791

Source: Gergis, J., Karoly, D. & Allan, R. (in review). Australian Meteorological Magazine

- Temp (and MSLP) displays a seasonal cycle remarkably close to modern day climatology of Observatory Hill (Sydney)

- Useful for cross verification documentary record, extended palaeo calibration

- Contributes to global ‘data rescue’ efforts of the ACRE program

National Library of Australia’s newspaper database

- Imaging early Australian newspapers: great source of weather data

- Sydney Gazette published daily temperature, pressure, wind and remarks from March 1803

- Sydney’s temperature and pressure records could potentially be extended back to early C17th

- Other regional centres?Source: Sydney Gazette, National Library of Australia

Contribute data from the SE Australian region to improve spatial and temporal coverage in global reanalyses

Source: Rob Allan, ACRE project

Summary

3) Just begun a project to develop seminal multi-proxy temperature, rainfall and pressure reconstructions for the Australian region > ARC Linkage proposal submitted, positive assessor reports, funding announcement mid May 2009

1) South-eastern is getting hotter and drier: 12 years of rainfall deficiencies, palaeoclimatology can help resolve decadal to centennial scale climate variability

5) Plans to contribute early instrumental data (temperature, pressure, rainfall) for south-eastern Australia to the ACRE project

2) Multi-proxy palaeo science is still in its infancy in Australasia…but there are opportunities to develop ‘meta data sets’ needed for long-term climate analysis

4) First large-scale effort to examine Australian documentary records for past climate information > following European methods of time series development/ reconstructions

Source: National Gallery of Victoria

6) Palaeo science is critical for improving estimates of the range of natural climate variability > bringing palaeo and climate communities together to develop science that could help mitigate the socio-economic impacts associated with future climate change

Hail storm near GPO on Bourke Street (intersection with Elizabeth St) in 1901Near modern day ‘Bourke Street Mall’

jgergis@unimelb.edu.au