Archives for April 29, 2005

After Michael Duffy interviewed Prof Bob Carter on climate change on his ABC radio program Counterpoint, there was comment on at least one web-blog site.

John Quiggin wrote:
“It would be more accurate to describe Carter as a prominent research geologist with a personal interest in the issue of climate change, and a strongly-held view that Kyoto is a bad idea.
As regards the major issues, I see little evidence to suggest that Carter is any better informed than I am.”

Some of my geologist mates have interpreted this as a slight on their profession and an inference that geologist know nothing more than economists about climate.

I received the following from a geologist:

“Astonishingly, some persons appear to believe that geologists have no part to play in the current public discussion on climate change.

Geologists, as scientists, operate in deep time. They study environmental phenomena on scales commensurate with the earth’s dynamic and changing nature, over periods of hundreds to thousands to millions of years and more.

Geologists are therefore 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.

Using information from ice cores, deep sea cores, lake cores and other data, first year geology students the world over are taught:

1. That climate has always changed, and always will. Some of the climatic changes are due to slow trends, others due to sudden climate shifts whose origin is not yet understood.

2. That rates of ‘climate’change during the 20th century, as manifest from surface meteorological records of temperature, are in now way unusual in either their magnitude or rate of temperature change.

3. That the carbon dioxide content of the atmosphere in past times has not infrequently attained values of 1000 ppm or more (i.e. much more than a doubling of current levels), without any known adverse affects apart from the prolific growth of plant life, for which carbon dioxide is a powerful aerial fertilizer.

4. That over the last half million years the earth has experienced several glaciations and interglaciations. For the majority (>90%) of that time, Earth’s average surface temperature has been substantially, and often much, colder than today.

5. That the current warm period, called the Holocene, has already lasted about 10,000 years, which is the average length of earlier warm periods, and that beyond question Earth’s biggest near future environmental changes are going to be those associated with the onset of the next ice age.

6. Geologists freely admit, however, that it is not possible to predict exactly WHEN the next ice age will start, and also th at despite the magnificent climatic records that they have assembled, there are still many things about climate that are not understood.

It is strange that anyone would assert that geologists have nothing to contribute to the understanding of climate change.”

There is a transcript of the interview with Prof Carter at the Counterpoint site.