News & Media Opinion Pieces Our experiment with climate is dangerous – by Professor Peter Doherty, Laureate Professor

Our experiment with climate is dangerous – by Professor Peter Doherty, Laureate Professor

Our experiment with climate is dangerous – by Professor Peter Doherty, Laureate Professor

Professor Peter Doherty, is Laureate Professor, Department of Microbiology and Immunology, University of Melbourne – Friday, 5 June 2009, Published in the Medical Observer

SCEPTICISM is central to science. Denial is something else. Being sceptical by nature and training, I’ve read up on anthropogenic, greenhouse gas-induced climate change and am firmly on the side that says we need to act. (1)

In fact, I’d thought most reasonable people were convinced. Australian, US and UK public policy is certainly being developed accordingly.

It seems, though, that the senior geologist Ian Plimer is not only sceptical but in outright denial, a position he develops at length in a new book (2) that has received a great deal of publicity: Heaven + Earth: Global Warming The Missing Science.

Though the reviews by informed, active researchers (including other geologists) have been uniformly negative,(3) I’ve been reading it and have enjoyed his account of the deep geological history of climate change.

He leaves us in no doubt that humans will inevitably face a natural disaster that could well lead to our extinction. Should we do everything possible to leave stored energy reserves in the ground for emergency use by future generations while developing renewable alternatives now?

But how good is his case that the ever-increasing levels of CO2, N2O and CH4 in our fragile atmosphere don’t matter?

On the one hand, he sets up a straw man, saying protagonists identify increased CO2 levels as the sole cause of warming through the aeons, though it has always been my understanding that wobbles in the Earth’s orbit are a primary factor.

He also says: “Greenhouse gases act only as amplifiers.” Precisely! Think about a 1.1x amplifier effect on human body temperature. He makes the point that, in geo-history, rising CO2 levels follow natural warming. We’re doing the experiment of greatly increasing greenhouse gas levels ahead of time. How dangerous is that?

He’s scathing about the effort that active climate scientists (Mr Plimer’s an old ore geologist) make to develop an overall synthesis for policymakers and the interested public.

That’s the role of the Intergovernmental Panel for Climate Change (IPCC), a function of the World Meteorology Organization/UN Environment Program, which draws together complex data sets from areas as diverse as cloud and ice science, oceanography and coral biology.

Mr Plimer says the iconic “hockey stick” graph is a fraud and that the IPCC no longer supports this, though versions of the “hockey stick” are reproduced in the 2007 IPCC Report.

Read the report yourself or, if you don’t have that much time, download the technical summary that provides ample support for the hockey stick and lists “Robust Findings” and “Key

This is the stuff of complex science. The IPCC scientists do their best to present clear trends and provide a spectrum of relevant data and models. Beyond that, they also take great trouble to identify where current understanding is incomplete.

New numbers are coming in all the time from ever more sophisticated and comprehensive measurement systems. That’s what’s missing totally from Mr Plimer’s book: the acknowledgement of uncertainty and the true scientist’s fascination with data!

Do you, as a medical practitioner, trust absolutism in the analysis of a problem that is multifaceted and complex? As an active and frequently surprised (by new data) research scientist, I certainly do not.

Professor Peter Doherty is Michael F. Tamer Chair of Biomedical Research at St Jude Children’s Research Hospital and Nobel Laureate for Physiology or Medicine. He received the Nobel Prize in 1996 and was Australian of the Year in 1997.

This article appeared in the Doctors for the Environment, Australia column in Medical Observer

(1) Doherty, PC. A Light History of Hot Air. Melbourne University Publishing, 2007.
(2) Plimer, IR. Heaven + earth – global warming: the missing science.
Connor Court Publishing, 2009.
(4) , go to Fig T8.20 and to p81; also see the paper of Mann et al
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