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The Age (Melbourne)

Letters, September 30-31, 2004

 

Degrees of Difference on Global Warming

I would like to take issue with a number of points made in Melissa Fyfe’s article on the impending visit by renowned British environmentalist David Bellamy (The Age, 27/9).

First, the degree to which the human burning of fossil fuels has contributed to 20th century warming remains unproven and extremely controversial, and many outstanding scientists can be found on both sides of the debate.

Second, Professor Bellamy is entirely correct when he asserts that higher levels of carbon dioxide in the atmosphere act as a plant fertilizer, and hence encourage the greening of the planet.

And, third, Professor Bellamy’s view that natural climatic cycling explains most of the changes in estimated global temperature over the last century is shared by thousands of other knowledgeable professional scientists.

Professor R.M. Carter
James Cook University
Townsville

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Andrew Watkins replies (Letters, Sept. 31st)
Dilettantes on global warming

How ironic: on the day after NSW records its hottest September temperature on record, in the month the US gets hit by its fourth major hurricane, and in the year after the third hottest year in the past millennium, Professor R. M. Carter - a geologist at Queensland's James Cook University - suggests (30/9) that there is a "debate" about climate change.

Well, among the fossil-fuelled scientists there may well be disagreement. But among meteorologists and climatologists - people who have devoted their professional lives to studying and understanding the what, when, where, hows and whys of the earth's atmosphere - there is simply no debate. Climate change is real. And it is here now.

Sounds a bit like the smoking or asbestos "debates" all over again. Funny how the medical professionals were right all along . . .

Dr Andrew Watkins
Hampton East

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David Jones replies (Letters, Sept. 31st)
Listen to the experts

I can attest that Bob Carter is right on one point: that thousands of knowledgeable professional "scientists" believe recent warming is a natural cycle. Unfortunately, what he fails to mention is that these "scientists" are overwhelmingly geologists, economists, biologists, and the like (with the occasional elderly "conservationist") who are not experts on climate change.

Fortunately, for those who prefer an informed and expert response, the scientific literature on climate change is periodically reviewed by the United Nations Intergovernmental Panel on Climate Change. Its most recent report, published in 2001, concludes that "most of the observed warming of the last 50 years is likely to have been due to the increase in greenhouse gas concentrations".

Dr David Jones
Ferny Creek

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Bob Carter comments

Drs. Watkins and Jones put arguments that are all too familiar.

First, they attack the man rather than engage in scientific debate, referring to “fossil-fuelled scientists” as a term of disparagement and guilt-by-association.

Second, they quote recent extreme weather events in a way that implies the events are a result of human-caused global warming. In so doing, they reveal their utter lack of understanding of the difference between weather and climate (see below).

Third, they deny the existence of authentic debate regarding human-caused climate change, and claim instead that the authority of the IPCC “consensus” should carry all before it. Quite apart from the fact that science operates on logic and not authority, that their assertion is completely threadbare can be determined by consulting the following sources.

And fourth, they claim that only meteorologists and climatologists are competent to pronounce upon climate change, practitioners of scientific disciplines other than these being “not expert”.

This claim, breathtaking in its arrogance, is simply silly.

Meteorologists, arbitrarily, have chosen 30 years as the period that separates (shorter) weather phenomena from (longer) climate phenomena. We have some sort of instrumental record of weather/climate for ground-based meteorological stations from a variety of locations for about 150 years. We have accurate satellite data on truly global weather patterns since 1978, i.e. 27 years, which is less than the period necessary to even start to make statements about climate trends.

Meteorologists, who do indeed dominate the IPCC and public discussion on climate change, are therefore not in a strong position to comment on real climate change, as opposed to report on the output of computer models which summarise how they think that climate might change.

Geologists, as scientists, operate in deep time. They study environmental phenomena on scales commensurate with Earth’s dynamic and changing nature, over periods of hundreds to thousands to millions of years and more. Geologists are therefore precisely the persons to whom one should turn for accurate advice on whether current meteorological trends, if projected as climate trends, are in any way unusual when compared with Earth’s past behaviour.

Dr Jones therefore gets it right when he acknowledges that thousands of geologists “believe recent warming is a natural cycle”. It is a pity that he is so unable to learn from them.

 Bob Carter

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