Science Show

Using ice cores from Antarctica and Greenland, the sun's activity over the past 10,000 years can be reconstructed. It shows cycle variations. Ken McCracken suggests there are two contributors to climate change - increased carbon dioxide and methane due to human activity and a changing sun cycle. He says we're entering a cooling period from the sun, as sun spots decrease in frequency, but we shouldn't diminish our concern or efforts in reducing production of greenhouse gas.

Transcript

Robyn Williams: One winning science communicator who began way back as an astronomer in Hobart, Ken McCracken has now produced a lively book of his story called Blast Off. In it he questions one aspect of global warming research, like this:

Ken McCracken: Now in my geriatric years, I'm now conducting what I call 'Bronze Age space science' where using ice cores from Antarctica and Greenland we're able to reconstruct what the Sun was doing, certainly for the last 10,000 years, with great ease. That has shown me just how much the Sun has varied in various cycles; a 2,300-year cycle which most people don't know much about, a 208-year cycle and so on. And this made me look at what we were doing, and I have to make it clear, I believe that the CO2 and CH4 contributions to climate are real, but I am also very convinced that...looking at historical records from glaciers and from other sources, carbon-14, all of this says to me that the Sun has been doing as well and that we have two culprits who are the cause of this.

My great concern has been that I could see that one of the culprits was about to go quiet. In other words, the Sun was about to go quiet. This was clear it was going to happen, and that when that happened the world will go cool for about 20 years, and all the political will might evaporate to do something which I believe needs to be done. The evidence is not all in yet. One of the things that happened was that the International Panel on Climate Change in their third report gave a fairly substantial contribution coming from the Sun.

In their fourth report they cut it by a factor of three. The evidence to date, which I was alluding to there, was that I think they made an error. They were very good scientists. One of them, in fact the leading member of that committee was a young lady trained in Broken Hill...they, I think, misjudged some of the evidence. Right now the Sun is going into a period of massive lack of sunspots. Still the jury is out, but if in about six months we don't have much more solar activity, we know that we're going back into an environmental situation like 1900 which was when it was quite cold.

But the other issue then is that on the other hand we're learning about this 2,300-year cycle. The cold part of that was in around about 1400, and when we come out of the little cold cycle we're going into now for maybe 20 years, we will be back into this deadly warming 2,300-year cycle which will just...the Sun itself will keep ramping up, as well as the CO2.

Robyn Williams: So you're saying don't be deceived by this short cool spell.

Ken McCracken: I'm certainly saying do not be deceived, be concerned also that the Sun is going to keep adding to CO2 after the short period. Scientists find it difficult to communicate 'on this hand, on that hand'. Economists can get away with it, scientists can't. But that's exactly what I'm saying; we have two factors here, one which in the short term is going to look like the scientists have been wrong, in the long term they are right.

Robyn Williams: Ken McCracken, and that idea was the feature of a cover story from New Scientist magazine a couple of weeks ago. Dr Ken McCracken talks to me at length next Thursday evening at 7:30 on In Conversation, themes from his book Blast Off.

Guests

Ken McCracken
Formerly with CSIRO

Publications

Title: Blastoff - Scientific Adventures at the Dawn of the Space Age
Author: Ken McCracken
Publisher: New Holland

Presenter

Robyn Williams

Producer

David Fisher

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