Why I disagree with Lord Lawson

In August 2012, Nigel Lawson presented a paper to the Erice conference entitled Rational climate economics.

Early in the paper he goes in for some political knockabout at the expense of climate scientists:-

"There is now a new religion – the AGW [anthropogenic global warming] religion, of which scientists are the new priesthood, preaching their dogma with precisely the same claim to authority as the mediaeval catholic church."

He goes on: "The truth is, as the best scientists recognise, that the greenhouse effect is a highly complex phenomenon, and the scale of the climate sensitivity of carbon is hugely uncertain."

In spite of what he says about the uncertainties, towards the end of the paper he displays his confidence that we need take no action to reduce the risks of seriously harmful climate change. He says we can rely exclusively on adaptation to global warming as the most cost-effective response. There appears some inconsistency here between the alleged hugeness of the uncertainty and his confidence that global warming will be mild enough for us to cope with through adaptation.



I hope he is not implying that uncertainty is an excuse for ignoring the risks. I doubt if he would advise people not to insure against fire because it is uncertain that their houses will burn down - or that it's safe to play Russian roulette because there is no certainty that you will get shot.

Then he says:-

"...the greenhouse effect is only part of an even more complex and only partially understood overall climate system, and the notion that this can be reliably captured in a computer model is arrogant folly."

I don't remember a respected climate scientist ever claiming that a model can capture the full complexity of what is being modelled. This sounds like a simple insult directed at climate scientists, but is fortunately a pale reflection of the treatment some climate scientists in the USA face from some politicians. Unfortunately Lawson doesn't tell us where he thinks the main climate models should appear in a scale between totally useless and gospel truth. This merely tells us that he enjoys a bit of political knockabout, particularly at the expense of climate scientists. 

The central part of the paper is a demolition of the Stern review of the economics of climate change in which he summarises a recent critique by Peter Lilley. I had my own reservations about the Stern review and I'm not proposing to talk about the critique. However, Lawson's later comments in his paper are interesting.

He says that Stern and his team at the Grantham Institute are now falling back on the "Weitzman thesis", that "we cannot rule out the possibility that, however small the risk, global warming will increase to the point where it threatens the very survival of humanity on this planet." It is this very idea that dominates my own thinking about global warming. It renders meaningless the sort of cost-benefit analysis attempted in the Stern review.

Lawson thinks the Weitzman thesis is "absurd" for two reasons: firstly  
"this climate Armageddon can occur only if the climate sensitivity of carbon is very high indeed" (remember what he said about its being "hugely" uncertain?) and, secondly,  
"there are a host of possible planetary emergencies .... We simply cannot spend unlimited resources on seeking to eliminate them all. And common sense suggests that the menace of manmade global warming, so far from being, as Weitzman claims, in a league of its own, is probably the least of them."

I am unconvinced by both of these arguments. From what I have read about paleoclimatic studies, it appears that the climate sensitivity of carbon is, in fact, very high. For one explanation of how manmade carbon emissions could trigger a runaway greenhouse effect that makes our planet utterly uninhabitable, I recommend Chapter 10 of James Hansen's Storms of my grandchildren, where he describes how Earth could follow a similar path to Venus, which has a surface temperature of over 400C. This may only be the view of one (albeit very distinguished) climate scientist and continuing research may prove Hansen wrong. In the meantime I see no reason to rule out the Venus syndrome as a possible scenario that we need to take into account.

Lawson's idea that we can rule out the possibility of a lethal runaway greenhouse effect strikes me as being absurdly complacent.

Lawson's second reason, that we cannot single out global warming as a uniquely serious threat, depends on his first reason. No other global threat that I know of, with the possible exception of an asteroid strike, threatens the extinction of humanity. As long as climate sensitivity to carbon remains "hugely" uncertain, global warming does appear to be a uniquely serious threat.

Later in his paper, Lawson discusses the moral dimension:-

"Even if (and I rather doubt it) we in the western world feel that we are rich enough to move from relatively cheap energy to much more expensive energy, the notion that the developing world should unnecessarily impoverish its people by doing so is, I believe, profoundly immoral.

"Particularly when, in their case, impoverishment means, for hundreds of millions of their people, destitution, malnutrition, preventable disease, and premature death."

Lawson seems to think that only by burning fossil fuels can developing countries tackle malnutrition and disease. That strikes me as questionable, to say the least.

"All this, moreover, in the name of arguably benefiting distant future generations who, thanks to economic growth, will be many times better off than those who are asked to sacrifice their living standard, and that of their children, today."

Again, this argument depends on discounting the possibility of catastrophic global warming. Even if we ignore the longer-term risk of the complete extinction of humanity, it still seems to me highly possible that 4 or 5 degrees of global warming over then next century will render the lives of billions of people nasty, brutish and short. This possibility contrasts starkly with Lawson's vision of future generations "many times better off" than today's. Lawson seems to assume that growth in living standards will continue into the indefinite future - that technological progress and the accumulation of capital will reliably outweigh population growth, land shortage and the increasing cost of accessing dwindling reserves of convenient energy and raw materials. I find that assumption very questionable.

Lawson seems to be ignoring the risks to future generations in order to preserve business-as-usual for those alive today. A drunk driver similarly puts the lives of others at risk for the sake of his own convenience. That's how I view the morality of Lawson's position.