Greenhouse in Australia, 50 Years On

by Professor Graeme I Pearman AM, FAA, FTSE, FRSV, FAMOS

In the early 1970s my CSIRO colleague, John R Garratt and I, were measuring vertical profiles of carbon dioxide above a wheat field in north-eastern Victoria.

Charles David Keeling earned renown as the world’s foremost specialist in atmospheric carbon dioxide studies through his persistence at developing a continuous and precise record of the carbon dioxide concentrations in the Earth’s atmosphere. Source: Scripps Institution of Oceanography, UC San Diego.

We discovered, almost by accident, that the concentration of carbon dioxide in the atmosphere was very close to that being observed by C. David Keeling at the Mauna Loa monitoring station in Hawaii[i].

This was a surprise to us, and we started to read about Keeling’s measurements, the only precision measurements at that time, and his suggestion that the concentration in the background atmosphere was increasing.

In 1973 we were quoted in the Bulletin as being sceptical about planetary warming. First, because there had been a significant period through the 1960s when global temperatures varied very little, later to be recognised as due to a period of exceptional volcanic activity. Second, because we were not confident that the concentration of carbon dioxide was rising, or indeed that human burning of fossil fuels could impact the concentration of the global atmosphere. Being sceptical, we thought that, perhaps, Keeling had drifting calibration standards.

Soon after, we established a significant atmospheric monitoring program. A month ago (March 20, 2022), was the 50-year anniversary of the very first high precision measurements of carbon dioxide made over south-east Australia from aircraft. Within a little over a year, this measurement programme convinced us that Keeling was correct, the carbon dioxide concentration was rising.

At that time there was a poor understanding of the global biogeochemical cycling of carbon dioxide; that is, if it is added to the atmosphere does it get soaked up by the oceans or the vegetation, or stay airborne? The net result of this was the establishment of a significant carbon cycle research effort that continues today[ii].

It appeared that about 57% of the carbon dioxide emitted from the burning of fossil fuels was remaining airborne. We developed ways of looking back in time at what had happened to carbon dioxide concentrations using air trapped in Antarctic ice cores. Today this allows our colleagues to chart this history over one million years. We also developed techniques to measure and interpret the isotopic composition of carbon dioxide, a key clue to the biogeochemical cycling of the gas.

Concentration of Carbon Dioxide from trapped air measurements for the DE08 ice core near the summit of Law Dome, Antarctica. (Data measured by CSIRO Division of Atmospheric Research from ice cores supplied by Australian Antarctic Division) 

It had been known for more than hundred years that increases in concentration were likely to warm the planet. So, in addition, CSIRO commenced work on the modelling of the whole climate system. But in the 1980s it was realised that very few of our Australian colleagues, across a wide range of different disciplines, were either aware of the potential of global warming, or seriously considering, from their own perspectives, whether it was of any importance.

So, in 1986, I contacted about 70 scientists around the country, experts in a wide range of disciplines, oceanography, agriculture, forestry, energy use, conservation, and so on, and asked them to spend time during the next 12 months to consider what climate change might mean for their respective discipline/sector. They were each provided with a climate scenario prepared by our colleague A. Barrie Pittock, projecting what, despite the limited understanding at that time, might happen to the climate of Australia over coming decades. This scenario was based on the climate differences under different average pole-to-equator temperature gradients, climate patterns in warmer and cooler years, and limited paleoclimate data. The scientists were asked to prepare a paper expressing their findings for presentation at a conference, to be called the Greenhouse 87 Conference, and to be held at Monash University in October 1987.

The Conference was attended by 266 scientists, some of whom were the ones who had prepared papers for presentation, but others who, in the interim, had become interested in the climate change issue. The Conference was opened by the Honourable Barry Jones and attended by members of the media. One of the outcomes – not the main objective of the meeting – was a rather significant reporting of the meeting in the media; the beginning of a programme of public communication on the existence of the climate change issue.

The following year, a second meeting was organised with the Commission for the Future, a consequence of which, in 1989, CSIRO and the Commission for the Future were elected to the United Nations Global 500 Honour Roll. The award citation ends with “no other organisation or nation has so far conducted any comparable public awareness programme on climate change.”

But the Greenhouse 87 Conference’s primary aim was to encourage research activities within all aspects of potential impacts, risks, and mitigation options. Contributors covered a wide range of issues related to hydrology and water resources, changes to the natural environment, agriculture, and societal impacts. The papers, after peer review, were published in a book.[iii]

This process was, of course, an uncontrolled experiment. But how else could we rigorously identify the potential risks of a changing climate to the Australian community, the economy, and its ecosystems, without serious research and underpinning knowledge development? We could never have anticipated the impact that this would have on the uptake of significant research throughout Australia on all sorts of aspects of the potential for a warming planet and the consequent changes to the climatic system.

So here we are in 2022. Greenhouse 87 is now almost 35 years ago. Action on greenhouse-gas emissions reduction has become urgent. No, it is not about what we do by 2050, but what we do by 2030, this decade. It is not only about what other nations do, but what we do. Australia was well served by the establishment of a community of climate-change scientists those 35 years ago, yet clearly, rather than provide us with a rationale/advantage for taking action, we have been laggards in the quest to minimise emissions and the consequential risks of climate change.

There are many potential reasons for this, a subject for another day. But perhaps there is a lesson in how not to incorporate emerging scientific knowledge into both private and public sector strategic risk assessments, and decision making. Perhaps it also tells us something about the evolution in recent decades of the perceived role of science in modern societies.

[i] Pearman, G.I., J.R. Garratt and P. J. Fraser. (2018). CSIRO High-precision measurement of atmospheric CO2 concentration in Australia. Part 1: Initial motivation, Techniques and aircraft sampling. Historical Records of Australian Science, 28(2) 111-125.

Pearman, G.I. and J.R. Garratt (2022). Carbon dioxide measurements above a wheat crop. II CO2 flux density and the effects of diffuse radiation. JAgrForMet.,DOI.10.1016/j.agrformet.2022.1089440.

[ii] Pearman, G.I., J.R. Garratt and P. J. Fraser. (2018). CSIRO High-precision measurement of atmospheric CO2 concentration in Australia. Part 2: Cape Grim, surface CO2 measurements and carbon cycle modelling. Historical Records of Australian Science, 28(2) 126-139.

[iii] Pearman, G.I. (1988). Greenhouse gases: evidence for atmospheric changes and anthropogenic causes. p.3–21 in Greenhouse: Planning for Climate Change. G.I. Pearman (Edt.). Melbourne: CSIRO. 752pp.