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A response to my critics on global warming

25 October 2013

9:30 AM

25 October 2013

9:30 AM

My Spectator cover story on the net benefits of climate change sparked a lot of interest. There was an explosion of fury from all the predictable places. Yet not one of my critics managed to disprove my central assertion, that climate change is probably causing net benefits now and is likely to continue doing so for some decades yet.

I’ve written responses to some of the critical articles and reproduce them here.

1. Duncan Geere in the New Statesman.Screen Shot 2013-10-25 at 09.23.59

Four paragraphs in his piece in turn begin with ‘He’s right…’ so I am glad that Geere confirms that I am right about all my main points. If you read my article you will find that each of Geere’s assertions about the eventual harm of climate change are also in my piece. For example, I say:

‘Even if climate change does produce slightly more welfare for the next 70 years, why take the risk that it will do great harm thereafter?’

I do not ignore sea level rise: and anyway it is taken into account in all of the studies collated by Prof Tol, on whose research my piece was based.

Geere’s main point, that the graph of benefits starts declining at 1C above (today’s) is very misleading. What this means is that the benefit during one year is slightly smaller than the benefit during the year before, not that there has been net harm during that year. Geere seems to have misunderstood Tol’s graph.

My points about probably fewer droughts and probably richer biodiversity are grounded in the peer reviewed literature. Many models and data sets agree that rainfall is likely to increase as temperature rises, while the evidence for global greening as a result of carbon dioxide emissions (and rainfall increases) is now strong. Greater yields means more land sparing as well.

The main point I was trying to make is that very few people know that climate change has benefits at all, let alone net benefits today; even fewer know that it is likely to have net benefits in the future for about 70 years. This fact, which Mr Geere confirms, is worth discussing. Judging by the incredulous reaction to my article in some quarters, this was indeed news to many people.

I note Mr Geere has nothing to say about the harm being done by climate policies to the very poorest people in the world. A peer-reviewed estimate is that 200,000 people are dying every year because of the effect of biofuels on food prices. Western elites may feel comfortable about this, but I do not, and I think a serious debate about whether some current policies (as opposed to others) do more harm than good even in the long run is worth having.

2. Barry Brill

I was intrigued by Barry Brill’s comment on my article, posted at Bishop Hill website, which argued that I had probably been conservative in my assessment of net benefits:

‘The 1°C rise mentioned by Mr Geere has its base in 2009. As the IPCC says that global surface temperatures have increased by 0.85°C since the pre-industrial era, this point of maximum benefit is about equal to the 2°C target set by all UNFCCC conferences since Copenhagen.

‘At the rate of warming recorded in the recent AR5WG1 SPM (0.12°C/decade since 1951) it will be well after 2100 before even this level of diminishing benefit is reached. The IPCC says that the historic rate won’t increase unless the TCR is above about 1.5°C – which seems unlikely in view of recent studies.

‘The series of published economic studies relied upon by Professor Tol are based on the IPCC’s earlier assessment reports, which were blithely unaware of the “hiatus”. Allowance needs to be made for at least three new factors:

‘(1) The hiatus has already set the timetable back by about 17 years;
(2) The models assumed a Best Estimate for ECS of 3.0°C. The consensus behind that figure has now evaporated;
(3) We now know that natural variation (or the Davy Jones hypothesis) regularly offsets the effects of AGW.

‘All these factors suggest that Matt Ridley’s timing is extremely conservative. Any warming occurring in the 21st century is likely to be a great boon to planet Earth and its inhabitants.’

3. Bob Ward

My response to Bob Ward’s article on the LSE website and his splenetic tweets was as follows:

This week Bob Ward twice repeated in published form a claim that he surely knows to be misleading. It concerns the number of people who die in winter versus summer. Both Bjorn Lomborg in the Times and I in the Spectator have cited studies showing that there are more excess deaths in winter than summer in most countries. Mr Ward does not dispute this. But he cites a Health Protection Agency report which argues that by 2050 winter deaths in the UK will probably fall less than summer deaths will rise, and argues that this means that climate change will then be doing more harm than good in this one respect at least.

Yet the very source he uses states that the increase in summer deaths reflects “the increasing size of the population in most UK regions during the 21st century.” (p41) It goes on to show that if you hold population constant, projected climate change will increase heat deaths by 3,336, but reduce cold deaths by 10,766.

Anybody can make a mistake. But surely it was impossible to miss the HPA’s explanation? Yet in the last ten days Mr Ward simply repeated the error twice, in an article on the Grantham Institute’s website attacking me and in a letter to the Times this week attacking Lomborg.

Lomborg has now written to the Times pointing out that all three of Ward’s points in his letter are wrong:

‘First, he claims 21 world-leading economists and I neglect the health impact of tobacco. Wrong. On page 18, page 228 and 17 other places we write how tobacco is a huge problem, almost verbatim what Ward claims we’re ignoring.

Second, he insists climate change cannot be a present net benefit. Wrong. This is corroborated by the most comprehensive, peer-reviewed article, collecting all published estimates showing an overwhelming likelihood that global warming below 2oC is beneficial.[ii]

Third, he claims that the Health Protection Agency shows warming will lead to 4,000 more deaths in the 2050s. Wrong again. The HPA is clear that more deaths are a consequence of many more people in the UK by the 2050s. With a constant population HPA shows warming will lead to 7,000 fewer deaths.’

Mr Ward’s latest attack on my Spectator article, in which I argued that the evidence suggests probable net benefits from warming till about 2080, is an egregious example of his aggressive style. He called my article ‘ludicrous’ and attacked the Spectator for the “howler” of publishing it. Yet his own riposte is highly misleading.

He says the average temperature increase expected is ‘much lower than the top of the range of projections’ from the IPCC. Well, indeed – that’s the very meaning of the word average, that it’s less than the extreme. And he says that the IPCC’s ‘high’ emissions scenario suggests sea level ‘could’ be higher than the average projection. Indeed. I was careful to say in my article that I was talking about central estimates, not high-end projections. Either Mr Ward is simply unable to grasp this point or he was being deliberately mendacious in implying that the extreme scenarios are likely to happen.

On the effect of carbon dioxide on global vegetation indices, one of the main ways in which carbon dioxide emissions are benefiting the planet, Mr Ward is entirely silent. He simply ignores the data I cite showing a net global greening in all types of ecosystem over the past 30 years as measured by satellites. Yet he implies that carbon dioxide fertilisation is a myth. Has he not read the Donohue paper or examined the Myneni data? It’s easily viewed on the internet.

I am happy to debate the benefits of climate change with anybody, and I stressed in my original article that there is no certainty about the future. I have never said we need to do nothing to head off the damaging effects of climate change towards the end of the 21st century. But I do think the fact, an under-reported one, that climate change has had net benefits so far should be discussed alongside the fact that many climate policies are doing real harm to people and ecosystems. Terms of abuse are not helpful.

4. Greg Barker, Climate Change Minister

Perhaps the most embarrassingly weak critique of my article came from a government minister, Greg Barker, who has developed a strange habit of stalking me on twitter with childish taunts and plain fibs. All very undignified.

In his letter to the Spectator he makes some bizarre claims about my argument. For a start, he has trouble with subtraction. 2080 minus 2013 is 67 years, not 57, Greg.

More substantively, he thinks that I want to do all sorts of things like stop preserving historic monuments and hack down forests. This comes from a man the direct effect of whose policy is to hack down forests in the United States so that wood chips can be burned in power stations, and to hack downrain forests in Indonesia so that land can be cleared to grow biofuels for cars thus driving up the price of food and killing approximately 200,000 people a year through malnutrition. It was the widespread use of fossil fuels that enabled the world to slow and in many cases reverse deforestation. One of the most deforestedcountries on earth, Haiti, relies on renewable fuel – what Greg Barker likes to call ‘clean’ energy – for almost all its energy.

It is precisely because I don’t want forests hacked down that I am sceptical about much renewable energy.

As for how Mr Barker concluded from my article that I want to stop preserving historic monuments, the mind boggles. I might much more justifiably conclude from Mr Barker’s support for wind power and bioenergy that he actually wants to starve people and cause them to die of hypothermia. The connection is far less fanciful than the one he makes. But I’d never stoop to making such an argument. It’s too silly.

Next week I will be voting in the House of Lords and will probably support Mr Barker’s government in relation to energy targets. He has a funny way of going about trying to get my support.

Mr Barker quotes Margaret Thatcher. So here are some of her words for him to ponder:

‘The doomsters’ favourite subject today is climate change. This has a number of attractions for them. First, the science is extremely obscure so they cannot easily be proved wrong. Second, we all have ideas about the weather: traditionally, the English on first acquaintance talk of little else. Third, since clearly no plan to alter climate could be considered on anything but a global scale, it provides a marvellous excuse for worldwide, supra-national socialism. All this suggests a degree of calculation. Yet perhaps that is to miss half the point. Rather, as it was said of Hamlet that there was method in his madness, so one feels that in the case of some of the gloomier alarmists there is a large amount of madness in their method.’

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