Is CO2 the most maligned gas in history?

The mining industry is one of the world's greatest emitters of carbon dioxide, and legislation to reduce emissions has a severe impact not only on existing operations but on the potential start up of new ventures. And all at a time when the demand for metals is growing, particularly with the electric vehicle revolution.

It is not surprising, therefore, that talk at major mineral processing conferences often drifts towards climate change and its causes. Mineral processors are not climate change scientists but they are entitled to their views. As is the veteran broadcaster Sir David Attenborough, who last week was the keynote speaker at the opening ceremony of the United Nations-sponsored climate talks in Katowice, Poland, the most critical meeting on climate change since the 2015 Paris agreement.

Sir David painted a truly apocalyptic vision of the future with the collapse of civilisations and the extinction of "much of the natural world".  "Right now," he said "we are facing a man-made disaster of global scale. Our greatest threat in thousands of years. Climate change". He urged everyone to change their habits, in particular avoiding air travel- a little hypocritical maybe, as he spends half his life in the air travelling to remote locations for his excellent natural history series.

Sir David's comments were the lead story on the BBC national news that evening. Not surprising as his views reflect the BBC's hard-line policy, an article in The Times (BBC freezes out climate change sceptics, September 8th 2018) reporting that science staff have been told that they need no longer invite those who deny anthropogenic global warming on its programmes, suggesting that allowing them to speak was "like letting someone deny last week's football scores". It is very noticeable that the BBC's references to climate change are almost always preceded by 'man-made', but what really angers me is the repeated assertion that "all scientists agree that climate change is due to the activities of man".

This is just not true. When I discuss the topic at conferences there are, of course, many who back anthropogenic warming, but there are many who are sceptics who question some, or much, of the science. Many, however, are outright deniers of man-made climate change and feel that it is more likely that the temperature rise is due to natural cycles. Geologists in particular tend to support this, claiming that they have seen it all before, although not literally, and some astrophysicists argue that the temperature rise is due to solar activity.

There was much intense debate on the blog a few years ago, and a very eminent geologist, Prof. Ian Plimer, Emeritus Professor of the University of Melbourne, presented some very convincing arguments against anthropogenic global warming, which led to some interesting comments, and a long response against his arguments by the University of Exeter's Dr. Stephan Harrison. Many geologists that I speak to support Plimer's views.

So where do I stand on this extremely complex topic? I have spent almost 40% of my life as an editor of a peer-reviewed journal and have developed a nose for sniffing out bad science and I have to admit that I have been very sceptical about some of the science advocating anthropogenic global warming. I am a great believer in the motto of the Royal Society, nullius in verba (take nobody's word for it) and believe that all scientists should question the work of others even though they may not be directly involved in that field.

If pushed I would take the view that climate change is mainly a natural phenomenon, to which we humans contribute but by how much nobody knows. The suggestion that a small increase in concentration of a trace gas in the atmosphere can have such a profound effect on climate, and on the acidification of the oceans, leading to the disappearance of coral reefs, is not easy for me to accept. The media regularly report that CO2 levels have increased by around 40% since pre-industrial times, and the temperature has risen by 0.8 C. A question that I have asked before, but have not really got a satisfactory answer to, is 'how do we know this'? How can we compare temperatures and CO2 levels now to those of pre-industrial times when there was then no real interest in these levels?

An increase in 40% seems a lot, but in absolute terms this is an increase in concentration from just under 0.03% to the present level of just over 0.04%. Can this small increase have such a profound effect? Many scientists are convinced that it can, as the Danish electrochemist Arrhenius showed in the early 20th century that without the greenhouse gases H2O, CO2, CH4, O3 and N2O, the surface of the earth would be about -20C , like the moon. In this complex mix CO2 is the gas which has the second largest impact on reducing the amount of long wavelength radiation emitted by the earth, warmed by the Sun, back to space. The most potent green-house gas is water vapour and rising temperatures increase the amount of this gas in the atmosphere. Other major green-house gases are hydrofluorocarbons, perfluorocarbons, sulfur hexafluoride, and nitrogen trifluoride. These are synthetic, powerful greenhouse gases that are emitted from a variety of industrial processes. They are typically emitted in smaller quantities than CO2, but because they are powerful greenhouse gases, they are sometimes referred to as High Global Warming Potential gases.

But suppose Plimer is right, and temperature rise is part of a natural cycle. The oceans contain trillions of tonnes of CO2 and a rise in temperature must, according to Henry's Law, release CO2 into the atmosphere, explaining the correlation between temperature and CO2 levels, the argument behind the climate change debate. The CO2 level would then be expected to lag behind the temperature rise, and there have been many articles in reputable journals over the past decade saying just this, although there have not been many reports of this in the media. So, does temperature drive CO2 levels, and not the other way round? Or maybe it is a combination of both?

What I find really hard to swallow, however, is that an increase in CO2 concentration from 0.03% to 0.04% can acidify the oceans to such an extent that Sir David Attenborough predicted in his superb series, The Blue Planet, that the coral reefs would disappear by the end of the century. The programme even had a ludicrous demonstration of this, showing that when acid was poured onto a piece of coral it bubbled and fizzed- of course it would.

Carbonic acid is one of the weakest of acids, but even so, an increase in ocean temperature must release CO2, so if indeed the rate of attack on the coral reefs is increasing, what is causing it? Well every hydrometallurgist knows that the rate of leaching increases not only with acid concentration, but also with temperature.

So back to my eponymous question. Is CO2 the most maligned gas in history? It is present in trace amounts in the atmosphere, it is not a pollutant and is essential for plant growth and the production of oxygen.

Is the emphasis on CO2 taking the pressure off the real killer in the atmosphere? Air pollution is one of the world's major causes of death, and one of the main culprits is NO2 in internal combustion engine emissions. Electric vehicles will play a major role in the reduction of such emissions, and the mining industry will be vital in producing the materials for these vehicles. Let's hope that it is not hamstrung by the need to spend billions on controlling its own CO2 emissions. Mining is the primary industry, which feeds all other industries, and without a thriving mining industry civilisations would indeed collapse. So if draconian cuts in emissions are imposed, maybe it could be considered as a special case? Very unlikely I would suspect.

I am expecting a bit of flak by publishing this post, but it is basically to solicit your views on this controversial subject. Do you believe that climate change is solely down to human activity, is it a purely natural phenomenon, or do you feel that it is probably a combination of both?

Twitter @barrywills