spiked-science | Article | Julian Hunt and Piers Corbyn: global warnings?

Coming as it did in the wake of storms that ravaged Europe, the global warming summit in The Hague in November 2000 could not have happened at a better time for environmental campaigners.

Deputy prime minister John Prescott had warned that the 'water floods' should be 'a wake-up call for everyone on global warming', and was subsequently 'gutted' at the failure of his attempts to broker a deal between the USA and Europe in The Hague. Eco-worriers had filled newspaper pages with warnings about the havoc global warming was wreaking around the world: not only with rising sea levels, flooding and stormy weather, but also 'the invasion of alien species in rural Britain'. Prince Charles preached - once again - about humanity's 'arrogant disregard for the delicate balance of nature'.

But while many seemed to take for granted that the autumn's storms were nature's punishment for our destruction of the planet, how much do we really know about the extent, and consequences, of global warming?

Julian Hunt (now Lord Hunt) was director-general and chief executive of the Meteorological Office between 1992 and 1997 (1), and is now professor of climate modelling in the Department of Space, Climate Physics and Geological Sciences at University College London (UCL). I met him in his UCL office. Piers Corbyn, founder and managing director of the forecasters Weather Action (2), is more of a maverick and, according to Julian Hunt, an academic 'outsider' who could be likened to Prince Charles: 'he's a gadfly. But we need them. They shake you up.'

Corbyn's brother, Labour backbencher Jeremy, is supporting an e-campaign to persuade the US congress to agree to cuts in carbon dioxide emissions - yet Piers has gone the other way, and is highly sceptical about current fears about global warming. 'This whole thing has a dynamic of its own', he told me, in at his office in London's South Bank Technopark. 'Journalists say one thing, scientists want funding and politicians want bandwagons. Put these things together and they build up steam and carry on.'

So what do Corbyn and Lord Hunt think about the assertion that the recent floods were the consequence of global warming? 'It is not quite as the ministers have said', says Lord Hunt, before conceding that 'there is an element of correctness in what they say. It is quite a complicated pattern'. According to Lord Hunt, the weather models 'certainly show that there will be periods when you would expect wetter winters', but this is a statistical extrapolation. 'What is not absolutely clear is that we will have strong and extreme events', he explains. 'What we can say is that we will have rising sea temperatures. Rising sea temperatures mean more water in the atmosphere. More water in the atmosphere means increased precipitation. But, of course, the rain could come down in a beautiful drizzle every day for three months in the winter, as opposed to a few tremendous events.'

What does Lord Hunt think of the government's reaction to November's floods? 'I think "wake-up call" and "this is consistent" is all right', he equivocates. 'I think scientists are - as you can imagine - always slightly cautious as to what is being said. But I think that politicians have got to take some of the cautious words of scientists sometimes and say "wake up".'

'I think scientists are always slightly cautious' explains Lord Hunt

Predictably, Piers Corbyn is more critical of the government's warnings. 'It's nonsense. The weather is not more extreme', he states. 'For instance, there is no evidence that a rise in temperature causes more tropical cyclones. If there's any evidence at all it is the opposite and oceanography, as far as the Atlantic is concerned, shows it actually is the opposite.' Research conducted at the Benfield Greig Hazard Research Centre (3), across the corridor from where Lord Hunt works, shows that tropical cyclones have, if anything, decreased in the northern hemisphere in the 1990s - despite it being the warmest decade on record (according to Corbyn, as a result of El Ninos).

Corbyn may be a maverick, but he is not alone in some of his views. A number of climate experts have argued that the heavy rainfall across Europe this winter had nothing to do with global warming but a well-known weather system: the North Atlantic oscillation (NAO). Atmospheric pressure which forms over the ocean is known to produce a wide variety of weather. When the NAO is in a 'positive' state winters are wet, mild and stormy; when it is in a 'negative' state, winters are dry, cold and calm. According to Dr David Stephenson of Reading University, records show the NAO has flipped between the two states since the 1800s, at random, with no sign of a permanent change (4).

The late Robin Stirling was another critic of the assertion that Britain's weather is more extreme. His book, The Weather of Britain, shows that Britain has experienced storms far worse - both in terms of wind-speed and the amount of rainfall - than in October and November 2000, which have resulted in the loss of many more lives. The autumn storms were not exceptional in terms of intensity or rainfall: they caused extensive flooding because of their accumulated effect. Britain has also experienced significant changes in temperature levels. Going back a few hundred years, the Little Ice Age in the northern hemisphere brought a cooler climate to Britain - with temperatures in London at times falling to -40 degrees celsius - and ice several feet thick in depth covering parts of the Thames. Going back several hundred years further, to Roman times, Britain's climate may even have been three or four degrees warmer than today (5).

Given the evidence to the contrary, why do we hold so strongly to the assumption that today's weather is more extreme? 'There's an important distinction between hazard and vulnerability', explains Lord Hunt. 'Hazard is the actual phenomenon and vulnerability is the effect on the community. So that if you have the same level of storms but everybody then lives on floodplains or the coast the weather is the same, but there is a much bigger insurance loss. So by comparison, although there's been a small change in the hazard, there is a huge change in the vulnerability.'

Nonetheless, Lord Hunt does believe we should be worried about global warming. 'The largest amount of climate- and weather-related deaths are nothing to do with the extremes of flooding or wind, but to do with heat', he says. 'In America, thousands of people die every year in heatwaves. If there are more occasions when it is hotter you will get many more people dying.' After a few quick calculations his estimates have reached 'thousands and thousands, in fact even tens of thousands'. But heatwaves in the northern hemisphere kill precisely because they are sudden and rare. Surely if heatwaves became more frequent, society would find ways of adapting to them. In Norway, for example, winter temperatures will frequently drop to -30 or -40 degrees celsius, and few lives are lost as a result. Yet similar temperature drops in Britain would have devastating results, because we would not be prepared for it. In fact, twice as many people die in Britain as the result of cold winter nights as they do as a consequence of hot summer days. You could even argue that global warming, in Britain, would cost fewer lives.

Not that we actually know how much the globe is likely to warm this century. There is no clear consensus on this vital question. Five years ago the Intergovernmental Panel on Climate Change (IPCC) forecast that the globe would warm by between 1.5 degrees and 3.5 degrees over the next hundred years. Now the range has widened to between 1 degree and 6 degrees. Why the increasing uncertainty? According to Lord Hunt, 'the IPCC has become more political' with more countries wanting to join and push their own agendas. Though he would not disagree with this explanation, Piers Corbyn emphasises the problems with the models upon which the IPCC makes its predictions.

Global warming, argues Corbyn, is caused by solar activity, not carbon dioxide (CO2) emissions. 'The levels of CO2 are governed by global temperatures which are governed by particles from the sun. Mankind is adding some CO2 - this is true - but at levels which will, generally speaking, be reabsorbed by nature quite rapidly.' Nature produces large quantities of CO2, but it also reabsorbs CO2. 'The add-on effect of man is like having a bath full of water with the tap on full and the plug open', he says. 'If you add a little more water - like pouring a cup of tea in there - all you get is a slight increase in the water level. And that is all man has contributed to Earth's carbon dioxide levels.' Corbyn goes on to explain that the biosphere is like a suction machine that removes carbon dioxide. 'It is very efficient, which is why we've got limestone everywhere. Take the white cliffs of Dover. That carbon dioxide was once in the atmosphere. It has been sucked out.'

Proposals to cut fuel duty on ultra-low sulphur diesel would raise temperatures, not lower them

When I put Corbyn's argument to Lord Hunt, however, he was not impressed. 'He has not done a calculation to demonstrate that. Anybody can produce an argument.' The point, according to Lord Hunt, is that 'yes, there's absorption in trees, and the amount that goes into and out of the ocean is very sensitive to temperatures. But it is like a positive feedback loop: a small change in carbon dioxide leads to higher temperatures. This leads to more water, and more water leads to more trapping [of sunlight] and so on. So it is a slightly unstable situation. That's the whole point'. He has more sympathy with Corbyn's other argument: 'that, is solar variation. It is a very reasonable criticism of the earlier IPCC reports that this wasn't adequately allowed for.' It seems that we do not know enough about how much global warming is caused by changes in solar activity rather than man-made pollution.

Yet according to Lord Hunt, our understanding of the impact of pollutants on global temperature has vastly improved. 'The first big reports on climate change that came out in the early 1990s had very large predicted increases in temperatures - of five or six degrees - on average over the next 100 years. However, when they plotted these graphs back the predictions were clearly bigger than anything that was being observed.' The reason for this was that they were only considering the greenhouse gases, not pollutants that had the effect of reducing temperatures. 'They weren't considering the fact that combustion - burning forests, petrol and things - lead to small particles in the atmosphere that slightly reduce the amount of radiation coming in. These are called sulphur aerosols. When this effect was introduced, all the computer models dramatically improved in accuracy and made the predictions for the next 100 years considerable lower.'

Ironically, in a move designed to mitigate global warming, Chancellor Gordon Brown made a pre-budget proposal in November 2000 to cut fuel duty on ultra-low sulphur diesel. Given that the impact of car driving on global warming is minute, the difference that this fuel would make is negligible. But this negligible difference would be to raise temperatures, rather than lowering them.

As for carbon dioxide emission - if this does have a deleterious effect, how should we deal with the problem? Some scientists on the IPCC panel claim that the world should cut carbon dioxide emission by up to 60 percent if global warming is to be kept under control. But we can safely say that this will not happen. As Corbyn says, 'The economic interests are not there to close down industry'. Lord Hunt also recognises that dramatic reductions in carbon emission are not realistically achievable and believes that while reducing our emissions through the more efficient use of energy we should also develop hi-tech solutions to combat the effects of a warmer globe. This would include building defences to combat rising sea-levels. We should, he states, push ahead with the technology that would allow for the possibility of carbon dioxide being removed, solidified and dispersed at the bottom of the ocean, while recognising that in the short term it is impractical. And we must maintain our capacity for nuclear energy, he argues.

Lord Hunt believes we need to use science and technology to deal with the potential problems of a warmer climate. The frugal environmentalist ethic of 'doing without' and suffering for our sins does not feature much in his worldview. In the current political climate, this is refreshing. But he also seems excited by the green lifestyle changes we are more used to seeing advocated: like the possibility of consumers being told, in their energy bills, how much energy they have consumed relative to the amount expected of a 'good citizen'. Given that we have a government far more comfortable with small-scale bossiness than hi-tech changes, we know we can expect more bills - and fewer defences.

Helene Guldberg is managing editor of spiked

(1) See the Met Office website

(2) See the Weather Action website

(3) The Benfield Greig Hazard Research Centre research can be found at here

(4) Dr David Stephenson's research can be found here

(5) The Weather of Britain by Robin Stirling, 1997