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

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

2. Multi-proxy reconstructions of ENSO: AD1525–2002 Tree-rings Coral Ice Core Documentary • 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 Dec 1997-98 SST anomalies NCEP/Reynolds SST reanalysis

3. 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

4. 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 The ‘Big Dry’: SE Oz in its 12th year of drought Source: Australian Bureau of Meteorology

5. Is the recent drying in SE Australia extreme climate variability or unprecedented climate change? • 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 • Can improve estimates of natural/baseline climate variability by looking at pre-C20th records provided by palaeo and historical sources

6. Northern Hemisphere temp reconstructions • 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 Source: Mann et al (2008) PNAS 105 (36): 13252–13257

7. Southern Hemisphere temp reconstructions IPCC 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

8. 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

9. PARTNER ORGANISATIONS Bureau of Meteorology (Karl Braganza) UK Met Office Hadley Centre Murray–Darling Basin Authority VIC Depart Sustainability & Environment Melbourne Water National & State Libraries Australasia National Library of Australia State Library of NSW State Library of VIC Powerhouse Museum KEY INVESTGATORS Joelle Gergis, Uni Melbourne David Karoly, Uni Melbourne Neville Nicholls, Monash University Rob Allan Met Office Hadley Centre Chris Turney, University of Exeter Andrew Lorrey, NIWA Don Garden, University of Melbourne ARC Linkage 2009 proposal: multi-disciplinary research team, 10 partner organisations (submitted Nov 2008) • 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

10. 1. Annually resolved palaeoclimate records: 200–500 yrs 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) Tree rings Coral Speleothem Antarctica Ice core

11. 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

12. 2. Documentary records – our early scribes Governor Arthur Philip Lieutenant David Collins Captain John Hunter • Weather diaries/ship logbooks • Newspapers • Annual gazettes/almanacs - 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)

13. Colonial documents contain weather information Source: David Collins (1796). An account of the English Colony at New South Wales

14. Quantifying documentary accounts of past climate Source: Royal Botanic Gardens, Sydney 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) - 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

15. 3. Early instrumental data - 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

16. 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

17. 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

18. Contribute data from the SE Australian region to improve spatial and temporal coverage in global reanalyses Source: Rob Allan, ACRE project

19. Summary 1) South-eastern is getting hotter and drier: 12 years of rainfall deficiencies, palaeoclimatology can help resolve decadal to centennial scale climate variability 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 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 4) First large-scale effort to examine Australian documentary records for past climate information > following European methods of time series development/ reconstructions 5) Plans to contribute early instrumental data (temperature, pressure, rainfall) for south-eastern Australia to the ACRE project 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 Source: National Gallery of Victoria

20. Hail storm near GPO on Bourke Street (intersection with Elizabeth St) in 1901Near modern day ‘Bourke Street Mall’ jgergis@unimelb.edu.au