QUARTERLY FOCUS
October 2008

Governor Phillip cops an El Niño

THE convicts and gaolers of the British settlement of Australia neared starvation during the period known as the “hungry years”, 1790-1793. Yet it took 200 years before Australian climate scientist Dr Neville Nicholls identified El Niño as the meteorological peril threatening Governor Arthur Phillip’s colony at Sydney.

Neville’s 37 years of research, focussed largely on developing climatic outlooks through greater understanding of the El Niño-Southern Oscillation (ENSO) phenomenon, has made him an international authority, most recently as a prominent contributor to the Inter- governmental Panel on Climate Change assessments.

His illumination of Phillip’s quandary is only a modest historical footnote, but it is typical of the research that helped him understand the theory and global impacts of El Niño. Neville’s ability to express complicated issues succinctly (and a wry sense of humour) earned him frequent media appearances following the launch of the Bureau’s Seasonal Outlook in 1989 and the community’s growing appreciation of El Niño in the 1990s. Neville knew that late 19th century climate researchers had pondered simultaneous droughts in India and Australia. Early researchers at the Bureau of Meteorology had made some statistical connections which suggested that atmospheric pressure differences across the equator had potential for use in seasonal prediction.

But without a theory and understanding of the processes involved, researchers remained somewhat sceptical about the value of the purely statistical analyses. Data from satellites and from buoys moored along the equator were to be vital in breaking the impasse.

“Put your money where your mouth is” is a familiar Australian challenge. During a severe El Niño, Neville did exactly that at a September 1982 Australian seminar on “Farmers and the Weatherman”. Armed with his new theory, he predicted that immediate, drought-breaking rains were unlikely because El Niño-related droughts usually lasted into the New Year. This was something of what meteorologists call an “heroic forecast”, where an expert appears to depart from conventional wisdom and collective calculations. He was doubted by some sceptical colleagues in Australia and overseas until the end of the drought arrived as he had predicted.

Searching particularly for a tool to ease Australian agriculture’s vulnerability to “droughts and flooding rains”, Neville had sought El Niño clues in libraries near and far. Five hundred years of El Niño records were available from flood records on the Pacific equatorial coast of the Americas. Within Australia, he trawled the usual sources, especially libraries, newspaper files and the national archives. While useful rainfall records for Australia did not go back much further than the late 19th century, Neville was urged by his wife Jill, a librarian, to search the reports of the colonial governors to the colonial secretary in London. From Phillip onward, their drought references proved to be mostly associated with El Niño events documented from other sources.

A serendipitous discovery in the Bureau library led to the Australian Archives in Darwin, and the long missing observations of Darwin pressure observations from 1876-78, enabling comparison between the El Niño of 1877-78, one of the strongest known, and the severe 1982-83 event. To complement the historical detection, Neville drove a campaign to create a high-quality set of data from Australian meteorological records. Exhaustive studies identified some 200 reference climate stations with data from 1910, when the infant Bureau of Meteorology had set up an efficient and uniform national weather observing system. Specially created mathematical equations culled any suspect data.

Neville’s improved appreciation of the atmospheric pressure see-saw across the equatorial Pacific transformed our understanding of the phenomenon central to many Australian droughts. By 1989, Nicholls and his colleagues, and specialists in the National Climate Centre, were confident enough in the science to issue the pioneering Seasonal Outlook - a form of long-range forecasting of particular guidance to farmers.

Farmers and policy-makers were particularly impressed with his graph showing high correlation between Australia’s wheat production and the atmospheric pressure variations of ENSO. Related studies examined the impacts of ENSO on human health (including Australian encephalitis) and on native flora and fauna. Neville battled to make the complex statistical presentations more easily understood, emphasising that the outlooks did not offer deterministic forecasts, but a range of probabilities.

The man sometimes teased as “El Nifto” retired from the Bureau in December 2005, joking that he “had escaped without ever making a weather forecast - I was the first meteorological graduate to go straight into research”. He recalled “the exciting times, and fun, when you found out something no one had worked out before...and I enjoyed the battles with climate-change sceptics and vested interests”.

As Professor Nicholls, an Australian Research Council Professorial Fellow at Monash University, his restless imagination is now focussed on whether we can improve seasonal forecasts for tropical cyclones, and how we might use seasonal prediction skills to think more deeply about climate change.

- Mike Rosel, Public Affairs Group

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