Conspiracies abound. Now comes the latest: Channel 4 screened last week 'The Great Global Warming Swindle', a documentary which claims that it is 'a lie' that carbon emissions are causing global warming and that attempts to debate the subject are being suppressed.I hadn't wanted to spend time on this issue again (see comment re 'deniers' on my blog on 18th 2006) - but as several people have asked for comment I've cobbled together this answer from my own thoughts and others. There are indeed many reasons to dismiss this Channel 4 programme, but some important points do emerge and we should not make the mistake of ignoring them.
Last month, the Intergovernmental Panel on Climate Change (IPCC) - which brings together almost all the world's leading scientists in the field and all its governments - published its latest huge "assessment report", concluding that it was 90 per cent certain that human activities are heating up the planet. The conclusion was all the more authoritative as the IPCC is a cautious body that acts by consensus; all governments, including the US, have to agree its conclusions.
It is true some scientists still disagree - that is the nature of science - but their numbers are diminishing, and few are leaders in their fields. A recent survey of 928 published scientific papers found not one that dissented over the reality of global warming. All the main political parties accept climate change and the need for action. Even Bush admitted in January's State of the Union speech that the climate change presented "a major challenge".
Many who thought that there was now full agreement about climate change and that they could now get on with making the changes we need, will have to think again. This film and attacks on Gores' own CO2 emissions (see my blog 7th March 2007) are indications that the battle is still not won.
The programme...
Martin Durkin first achieved notoriety when his previous series on the environment for the channel, called 'Against Nature', was condemned by the Independent Television Commission for misleading contributors on the purpose of the programmes, and for editing four interviewees in a way that "distorted or mispresented their known views". Channel 4 was forced to issue an apology, but despite this they have not sought checks of this current programme.
Indeed already Carl Wunsch, from the programme states: "the context was not at all what we had agreed on....As I began to see ads for the program, I realized I'd been duped." See here.
On the programme Martin Durkin interviewed various well known climate-change deniers including Phillip Stott, Piers Corbyn, Nigel Lawson and Nigel Calder. Each of these sceptics have a point, but fail to give the whole picture and so draw the wrong conclusions.
Lord Lawson, for example agrees much with environmentalists saying there is "little doubt that the 20th century ended warmer than it began" and that "there is no doubt that atmospheric concentrations of carbon dioxide increased greatly" during it. He even agrees that it is "highly likely that carbon dioxide emissions" have played a significant part" in heating up the Earth.
Indeed he could not do otherwise: the basic science on this has been established and unchallenged for 180 years. Where dispute lies is in the contribution to warming that pollution has made, whether it will continue and what to do about it. Here I'll look briefly at the key arguments and show how they have been discredited.
Is the Sun to blame?
Michael Crichtons' novel 'State of Fear' started the ball rolling although it was some years before that I was given Nigel Calder’s “Manic Sun” - this controversial book claimed an alternative theory to global warming. The book was based on work by three Danish scientists who discovered correlations between quite complicated solar cycles and past weather patterns. The scientists claim this is a more accurate reflection than anything to do with carbon dioxide. Work with data from satellites showed the Sun to be in an energetic state, the most invisible radiations from it intercept cosmic rays that are always impinging on the Earth. The cosmic rays are important in initiating cloud formation, and clouds make a lot of difference to the weather, and cumulatively to climate.
However while the book and subsequent articles and further books make some useful contributions it is clear they are a long way from demonstrating an influence of cosmic rays on the real world climate. Variations in solar activity may have been responsible for past warm periods, though it's hard to be sure because we have been taking good measurements of it only since 1978. Certainly recent solar increases are too small to have produced the present warming, and have been much less important than greenhouse gases since about 1850. See here.
Questions about temperature?
The programme shows how studies of gases in bubbles of air in polar ice sheets reveal that in prehistoric hot periods temperatures began rising before C02 levels. So it is argued that increasing concentrations of the gas are the result, not the cause of global warming.
Temperature and C02 are indeed bound together: as one goes up, the other follows. Historically temperatures often started rising 800 years before levels of the gas, but this is irrelevant to what is happening now, because for the first time ever enormous amounts of extra C02 are being released.
The programme emphasises that temperatures in Britain and other parts of Europe were warmer in the Middle Ages than they are now. That may or may not be true - since no accurate measurements were taken it is hard to be certain. But, if so, it was only a regional effect: measurements of ice from the poles on which the sceptics place great reliance for other arguments show it did not happen worldwide.
Arctic ice shrink is exaggerated?
Skeptics claim that ice caps ebb and flow in size and their current shrinking is exaggerated. In contrast Al Gore suggests the Arctic is a "canary in the coal mine". He shows how since the 1970s the extent of the Arctics' ice cap has "diminished precipitously". If we continue as we are, it will disappear for part of the year and profoundly change the climate. Certainly part of the Arctics' shrinking is probably due to natural ebb and flows, but this has been increased by global warming caused by rising levels of greenhouse gases - and these continue to go up. The Arctic is likely to be free of ice by 2050, for the first time in millions of years.
Solutions to climate change will hurt the world's poorest?
This is the claim but infact renewable sources of energy should be the poor's salvation. They are abundant in the Third World and don't need costly distribution networks to get them to village.
Climate change hijacked?
Heres a view..."Petrol-guzzling 4x4s must be taxed, foreign holidays discouraged, TVs unplugged and lavatories left unflushed. After decades of waiting, the green movement has found the cause of its dreams: a crisis that gives them carte blanche to rule our lives?"
Myles Allen, of Oxford's climate dynamics group says: "That is the striking thing about global warming. It is a Christmas tree on which each of us can hang virtually everything we want."
Everyone of us can now use global warming as an excuse to tell us how to live. Some of this advice is sound - indeed much of it is good but some is clearly not. Mixed and confusing messages abound. Does carbon off-setting work? (see my blog on this for 23rd February 2007) What about road-pricing? (see my blog for 13th February 2007)
Critically in all this the lead must come from government. So far it hasn't.
One of the key ways forward that gets away from all the negative arguments about banning this or that is Personal Tradeable Carbon Allowances - my blog on 17th February goes into this in some detail.
But what if the sceptics are right?
Even if the sceptics are right and the bulk of the world's scientists wrong there is still a compelling reason for cutting carbon dioxide emissions. For rising levels of the gas - in an entirely separate process - are killing the world's oceans by turning them acid.
Plus oil and gas are running out - world discovery of oil peaked in 1964 and has been declining ever since, despite considerable improvements in technology, and there is no prospect of any significant large discoveries. We are currently consuming more than six barrels of oil for every one we discover. There is growing consensus that we are now approaching, or are even at, the world oil peak. We have longer for gas but which ever way we look at it we must move away from them.
The truth is that the real swindle is that such a one-sided programme can be presented as fact when the vast majority of scientists disagree with the conclusions. Such a move is dangerous when we are only just developing the momentum to find the solutions to this massive problem.
More info:
There are various responses to this Channel 4 show like science blog, 'Stoat' here, The Royal Society put out a news release here and The Independent also published a fair response which I have used to put this case above: 'Global warming: An inconvenient truth or hot air?'
Also see George Monbiot writing in The Guardian: "The science might be bunkum, the research discredited. But all that counts for Channel 4 is generating controversy." See here. And for more general stuff see Realclimate that covers many of the issues raised in the programme.
16/03/07: Just found this on MediaLens: a good look at the whole programme - look for 13th March 2007 entry here. See Ecologist here with Met Office comment here. Lots more info and letters to Channel 4 here. See also Royal Society rebuttal here.
