I find this whole global warming a con for the masses being exploited to enable governements to tax the people it is supposed to work for even more. It is the arrogence of human kind to suggest that we can effect a whole planet more than inter-stellar radiation and the sun. The fact that the sun has been more active during this rise in temperatures is dismissed. Recent experimentation has linked interstellar rays as having a possible effect on cloud formation. Yet this is not commonly discussed as scientists have a superiority complex and treat the public as dumbies who will not understand. This is possibly true for some sectors of society but instead of telling people, "You must do this" as per labour party docturine, actively put forward all information to the masses and let us decide. In England expeciallly, as we are taxed till we cannot absorb anymore taxes, this is a perfect excuse to raise more money on an un-proven, dodgy, eco theory proposed by the left. Debate first please.

Dean Cutler, Worcester, England

Its unfortunate that so many people, many of whom are scientists, are getting so emotional about this. Is humanity truly capable of real science when the ego repeatedly gets in the way?

The media only serves to complicate everything with an endless stream of hysterical articles, programmes, web-sites etc. It must be making a great many people huge wads of cash.

I'm glad to say I have no opinion on climate change.

Humanity is not enlightened. We are pathetic.

Jerome Thomas, Pelkington, Lancs

I really don't get why we need to lower our global temperatures. If you ask me, it's FREEZING here! Let's turn it up a notch a little, i kinda like 50C+ temperature ranges . ^_^

JC, Gold Coast, Australia, Queensland

Regarding the daft explanation that a small increase:

Is there any other "model" in nature where a tiny EFFECT "feedback" PRODUCES a major increase in the CAUSE? It sounds like a readymade excuse fto explain away the fact that the data doesn't fit the chosen theory. What hard evidence is there that might make one think that that this "CO2 feedback effect" model is correct? Some computer model? Based on what? Preconceived conclusions that CO2 and only CO2 causes global warming. Garbage in-garbage out!

So if the cult of global warming admits NO evidence against their model, it's not science at all, it's a religion.

One final thing, I hear Al Gore and his acolytes report ad naseum that the sciencetific consensus is that global warming is anthroprogenic. Well I'm sorry to wreck the game, but the scientific method does not turn on consensus. The only thing that counts are the facts, and the facts are not on Al's side.

Warren Rutherford, Saskatoon, Canada

1. If industrial emissions caused global cooling, why not solve the global warming problem by repealing The Clean Air Act?

2. What is the answer to the question as to how can the total of man-made greenhouse gases affect the Earth's atmosphere which is both billions of times greater in volume and is also constantly making changes of its own to its constituent parts?

Mr Alwyn Birch, Basildon, UK

In response to K. Michaels from Orem UT.

Can you please enlighten us as to what kind of aerosols could be released in to the atmosphere to promote cooling that would not produce acid rain. I assume that you have some knowledge of such chemicals.

Thank you for your response.

C. Allen, Salt Lake, Utah

All your FACTS to dispute the claims are theory. None of those theories have had supporting evidence.
Please if your going to publish conjecture ensure that is a good one.

Phillip S, Orlando ,

Quote:
"This was once the case, but it has been resolved now that initial measurement errors have been corrected "

Nothing better that to rewrite the story ...

Mannipulador, Greenland,

"Who do you believe? A psycho TV producer who has a history of manipulating scientists, interviewees, who has an ITV ruling against him
- or Nasa, Stephen Hawking, David Attenborough, The Royal Society..."

although Stephen Hawking is a good physicist does he have knowledge of global climates? Just becuase someone is a scientist doesn't mean you know everything - normally it's highly specialisation.

This is part of the problem the we are expected to believe anyone who can claim scientific credibility even when they know little more about the climate than a postman.

I notice this the "cosmic ray theory" is summarily dismissed by people with zero experience in that field. A career studying co2 levels leaves no time to keep up with any other field.

phil, herts,

Why any of you think scientists should bother to try and dig humanity out of the hole it has created for itself, beats me.

When you have finished restoring the atmosphere to the state it was in ~300 million BC, you will soon be gone, and the scene will be set for the return of the dinosaurs: the true Earthlings.

You are in a hole humans: keep digging!

Saurus, London, UK

I can't convince anyone of what to believe or not to believe, especially if you're set in your ways.

Supposing you do want to see the real science behind Global Climate Change, I suggest you read through this link to RealClimate.com They dissect all the false, inaccurate or disingenuous information provided in that program.

It also includes a letter from the scientist who explained CO2 in the oceans and his distaste for the program.

http://www.realclimate.org/index.php/archives/2007/03/swindled/

MIchael, Palm Harbor, Florida

It is worth it Tim, but it must be done in a more constructive way than the witch-hunt taking place now. Peoples liberties are threatened because some people try to use the environmental problem as an excuse to infringe their political idealogies upon us. So instead of promoting alternative fuel the try to ban all large cars or implement a maximum speed for all cars. Size and speed capability are irrelevant when the vehicle doesn't produce any CO2. Like the HUMMERH2O and the new BMW 7-series, both with hydrogen combustion engines for instance. Let peoples freely decide which route they choose, as long as it improves air quality. Freedom of choice.

Amzika, The Hague, The Netherlands

Phil Davis, in the past, natural variability in the climate triggered climate change. These days, we're introducing unnatural variability by putting the carbon stored in fossil fuels into the air. I would say that was a rather stupid idea - why stand up and rock the boat when there's waves enough already? For further information, see the Met Office site, www.metoffice.gov.uk.

TR, Oxford, UK

Could it be a scare perpetuated by Governments to save / conserve the dwindling stocks of fossil fuels, after all is technology that advanced to yet offer a long term alternative, is nuclear,solar and for that matter wind power the real answer to our energy requirements for the long term future. What better way to conserve existing stocks than to raise prices / taxes on their usage,something we are all burdened with and familiar with lately.
Meanwhile the scientists can buy some time to come up with the solution.

Keith Lamont Alexander, Inverness, Scotland

So then, if the large cooling that took place for 3 decades was caused by aerosols that man produced then that means man can easily cool the weather at will by releasing many more aerosols. Problem solved. And we can release just the right type of aerosols that dont produce acid rain. The authors of this article are dopes that are dupes of the status quo. They say they have answers for all the key points. Yet their answers are weak at best. They are struggling desperately to hold onto the big swindle. God bless their tiny minds.

K Michales, Orem, Utah

Even if there is a chance that we created global warming, isn't it worth taking action to prevent it so our children and grandchildren can live happily?

TIm, Huntington Beach, USA

The current greenhouse theory is old, old science which when used in the 1980s correctly predicted the next 30 years of warming. The consensus has existed, virtually unchanged for 30 years and through many changes of government. It may get overturned. I don't think so, so we ought to think about getting used to it.

Steve Milesworthy, Southampton, UK

One point nobody is making is that we have forgotten the importance of Popper and the useful role of doubt in scientific method. The IPCC/CO2 side of the debate (say, the believers) constantly trying to prove something. The agnostic side is trying to disprove something. Take a few examples:
1. Believers say CO2 raises the temperature. Agnostics point out the CO2 increases after the temperature rises and this looks like an effect, not a cause. Believers refuse to doubt the hypothesis about cause: they merely acknowledge that temperature rises make the sea give off CO2.
2. Believers say the green house effect is making the temperature rise. Agnostics point out that then it would rise faster in the top of the atmosphere than on the earth's surface, but the figures show the opposite. Believers do not doubt their original idea but change the data.
Of course, if the data is wrong this is important. But it is nuts to try to make your graph fit your theory: better to aim to disprove.

Mrs M A Westrop, Birmingham, ENGLAND, ENGLAND

As a non-scientist, my first take on anything I hear from scientific or government sources is one of skepticism. I then look at who is grinding which ax: Is it someone who has much to gain in wealth or power? Is it someone looking for fame or notoriety in a field of science?

I have doubted the theory of man made global warming from the beginning because all those who are professing to be able to read the minute amounts of data available have something to gain by making resounding "Sky is Falling!" pronouncements in one way or another. The billions of pounds/dollars spent in a blind flurry to prevent what may very well not be preventable, are ending up in someone's pocket, as is the fame/notoriety laurels falling on welcoming humble shoulders.

CJ, Bonney Lake, USA/Washington

Perhaps the biggest nails in the coffin of the man made climate change theory are that the percentage of CO2 that man is responsible for is so small, and that the earth was warmer than today prior to the mini ice age. One would expect these facts alone to have emerged to have been acknowledged in the press at large... sadly it appears that belief has become more important than actual science.

As for the effect of cosmic rays in relation to cloud formation - current research indicates this is true, and therefore the sun, through solar wind alone has a huge role in regulating the earths climate.

In relation to the dismissal of the suns affect on the climate expressed in the above article, what other factors explain the many, significant changes in climate that have occured throughout the history of this planet? In fact, stable periods of climate are the exception - change is almost constant.

Mark W., London, London

I think that it suffices to state that while we can all agree that our planet is warming, but that no one can agree on why.
Solar cycles, input/output of CO2 from oceanic sources, or other events.
I for one still find it a hard pill to swallow that humanity is powerful enough to effect the temps by just being alive, living, and breathing. We're awfully arrogant to think that we could have so great an affect on feedback effects, and planetary wobbles, etc.... Even volcanoes outdo us by 10000000 times, and our nuclear bombs are dwarfed by a single volcanic explosion.
If this is the case, then why not just start killing us off? Get rid of around 4 billion of us, and the rest can do as they please. But if you do-- please make sure I'm among the first to go. I want no part of this new world everyone seems bent on starting.

Me, Carson, USA

Hats off to channel 4 for challenging the widespread misinformation being presented to the public on the subject.
The Channel 4 documentary made perfect sense, and it's the first time for a while the public have been presented with an alternative to all the hysteria, which is so ably presented by the BBC.
It's impossible to explain previous climate episodes with man made c02 emissions, and I'm aware that the Sun goes through cycles of higher and lower energy output.
The public is largely unaware of all this, and we see letters in the local paper on a regular basis claiming that c02 is destroying the planet and must be eradicated, ignoring the fact that c02 is essential to life on earth.
This view is encouraged by the government, and belongs back in the days when people believed the earth was flat.
Climate change is normal, and something we may have to live with.
It seems that to challenge the man made theory, which has become a new religion, is to court ridicule.

J Corfield, Telford, UK

Claim: Ice core data shows that carbon dioxide levels rise after temperatures go up, not before

Fact: This is correct, but climate scientists have a good explanation. There is a substantial feedback effect – initial small rises in temperature lead to substantial release of carbon dioxide from natural reservoirs in the oceans, which then produce much steeper warming later on.

Complete NONSENSE. A rise in the temperature of the oceans causes a release of carbon dioxide, decreases in tempreature cause oceans to absorb CO2.. C02 cannot cause a temperature increase, so what does ? Solar activity (but no fat research grants for stating the bleedin' obvious !).

David Leigh, Lymington, Hants

Not many of the commentators here seem to actually want to know what is going to happen with the climate. Many stop thinking when they found a reason to rubbish a view they dont like. I hope science is a tool (sometimes precariously ) to find out from present indications what is a possible or likely future consequence of present action. Of course the rigorous reasoning that is necessary to give such an attempt a chance of matching prediction with eventual outcome is beyond the scope of this opinion airing site.
John Bentley and Alan please explain:
If you look at the shape of the temp. and CO2 curves from the ice cores, I find it striking that they show a gradual rise and a relatively sudden drop. That seems to me consistent with release of CO2 causing further release (e.g. through temperature increase) until the reservoir from which it comes is no longer able to supply CO2 through the same mechanism.
Excuse my ignorance! Can anyone tell me how ice cores keep a record of temp.?

Andreas T, London,

You wrote:

The mid-century effect fall came about chiefly because of sulphate aerosols – particles that have a cooling effect on the atmosphere. These are no longer produced so heavily by industry because of environmental regulations to combat other problems, such as acid rain/

So may be we are wrong after all to urge China to clean up its act as without the smokestack industries the warming will get even greater. It is warmer in Europe now precisely because there is less industry and the "global dimming" effect fell. What did they say about good intentions and hell?

Boris, Amsterdam,

The world is nuts, no one is interested in presenting facts , only in making a splash or headline .

Just today we were informed by another well paid quango , we are chucking 30 percent of our food away and the methane created would add to GLOBAL WARMING , via methane from the land fill .
Humpries swiftly disected the figure in half , as half is made up of teabags, bone and peelings !

As for the other half creating all the methane, they just forget that all modern landfills have methane extraction to create electricity..

I regret this global warming is just a bandwagon for anyone with any sort of an issue to hitch their horse to.. I wish we were given facts not hype . This government has a lot to answer for as they have turned spin into an art form

rgds

Bill, essex, essex

The Channel 4 program said the temperature of the other planets also relates to sunspot activity so it cant be caused by people. Has anyone rebutted that?

Brian Gilbert, Hampton, Middx

I was able to watch the video from a Google link.

I'm not in the UK, I live in California, and I've always thought that the whole global warming thing was kind of
similar to the Piltdown Man hoax that was all the rage in England many years ago.

Kudos to Channel 4 for presenting a more balanced viewpoint. Over here, it seems that you have to tow the party line with respect for global warming (and I thought that was the main point the film was trying to make). It may have gotten some facts wrong, but the more important issue is the scientific method, and all this political claptrap over the issue isn't worth it.

David Fox, Sunnyvale, California USA

I'm not convinced by his film, but this article makes me think Durkin's onto something. Nobody would bat an eyelid if he'd said "by 2050 London might be under 12 feet of water". In fact, they'd probably pat him on the back, and buy him a drink - he might even win an Oscar.

Suddenly, when the sceptical argument gets made, it gets forensically torn apart, and the remotest criticism of any part of it means the whole thing is trashed, and Durkin is made a great enemy of science. Everyone challenging him seems to be doing it on the flimsiest of reasons, and to score maximum moral points for themselves.

Durkin's expletives were understatements.

Dan U, Cambridge,

Matthew

Heard of the Emperor's new clothes? In God we trust (if we believe), everyone else we (should) check out. [BTW: science is about 'playing the ball, not playing the man'. He may be bonkers, but he could still be right - and you should care! To trust without question is to be lazy.]

Come on Mark, explain the 'critisisms' of your explanations on this board.

I for one want to be convinced that global warming isn't a swindle. The implications for the intelligence of the human race are too awful to contemplate otherwise.

Go on, give it your best shot! That would be a real debate.

Alan, London,

The CO2 lag does though present a problem when cooling starts though. If the climate is highly CO2 sensitive, the temperature should keep on rising for as long as CO2 does (i.e. a positive feedback loop). However, cooling sets in long before CO2 increases stop. This is strong evidence that CO2 sensitivity of the atmosphere is low.

Troposphere temperature rise is still controversial. Spencer and Christy are generally acknowledged as the leaders in their field, and they don't think that the warming (even after correction of the observations to fit with model data, which is not normal science practice) is anywhere near the modelled values (which should exceed surface warming).

The CO2-aerosol model is a complication that does not go well with Occam's Razor (i.e. simplest explanations are best), and how well does it (i.e. model outputs) cope with current anthropogenic aerosol output especially from China?

Dr Ian Blanchard, St Albans, UK

I'm a little confused: Small initial rises in temperature allow substantial release of CO2 which then causes steeper temperature rises later. This then causes even greater releases of CO2 which precipitates even steeper rises in temperature. When does it saturate? The ocean holds 50 times the CO2 (on average)than the atmosphere. but has a huge thermal inertia. How does the temperature rise reverse as in the Holocene period?

The second point is that the Peter Laut paper published in Journal Atmospheric and Solar Terrestrial Physics, vol 65, p 801 (2003) refutes Marsh and Svensmarks' paper (in Physics Review Letters vol 85, p5004 (2000)). He has Kristjansson quoted as private communication. For those who don't know, Physics Review Letters is a 'big hitter' journal which is widely read and more rigourously reviewed physics journal than the Journal of Atmospheric and Solar Terrestrial Physics. Why didn't Peter Laut publish a rebuttal in Phys Rev Letts if he is so sure?

MC, London,

Phil Davis says "So its not man-made then !!", ignoring the fact that this is talking about ice core data from tens of thousands of years ago. No-one disputes that temperature rises have happened in the past without human intervention. Although the initial cause wasn't a CO2 increase, the temperature rise caused the oceans to release stored CO2, causing a further rise.
Since we first used fossil fuels, we have been putting carbon dioxide that had been taken out of the carbon cycle millions of years ago back into the atmosphere. This causes a temperature rise, which then triggers the release of more CO2 from the oceans.

Denis Walker, Southend, England

John Bentley absolutely right. In fact, Mark Henderson's "explanation" (really hypothesis - a true scientist would know the difference)would ensure there would be exactly zero CO2 in the seas.

Have to say there are problems with his other "explanations" too.

Aerosols 'caused' the 3 decade dip? Or did we rig our models so that they could 'explain' it. A lot of modelling is about curve fitting - I know, I've done it.

Aerosols have decreased since the 70's - even with China's (largest and dirtiest ever) industrial revolution? Hmmm.

Measurement errors? Hmmm, always suspicious when some corrects the 'facts' to fit their theory.

Alan, London,

I was enjoying the article until I got to the last section 'where C4 got it wrong' which was not particularly objective. Objective science should be able to stand up to scrutiny such that where scepticsm arises the whole community do not shy away from tthe debate. Rather tthan personal attacks the focus of teh debate should be on substance. The only fact for me in the last section is that it proves that even 'real' evidence can be manipulated to suit a sceintifc stance. I am with Mikey on this - give us a live debate and may the best man win!

Jana, London, UK

There is not a wealth of info that can be manipulated to support the man made theory - all the evidence supports the theory, it doesnt have to be manipulated.

Who do you believe? A psycho TV producer who has a history of manipulating scientists, interviewees, who has an ITV ruling against him -

- or Nasa, Stephen Hawking, David Attenborough, The Royal Society, New Scientists, Science Magazine, The American Academy of Science, weather.com, the UN, in fact every major scientifc body in the world who all agree that climate change is man made, a massive threat whcih we are running out of time to solve. Please research - and you find anyone who diagrees, the first thing you should do is do a search of their name with Exxon - and see what comes up.

Matthew, London,

Whatever you believe, there obviously isn't enough evidence to prove conclusively that human input has any substantial affect on Climate change
There certainly isn't enough evidence to justify the Governments level of investment in rectifying the situation.
To spend billions of pounds every year on something that appears to be unproven is ludicrous.
Especially in view of the lack of investment taking place for essential services.
Until they can prove their case without doubt, there needs to be a huge reduction in funding.
Maybe the money saved could be re-directed to something that has a proven need.
The Health service perhaps...

Gary, Custom House, England

Ken May, I don't understand your point. what caused the first ice age? was it man making too many stone hammers?

dg, london, UK

If Mark Henderson's ice-core 'explanation' were true then we would expect an unlimited runaway increase in temperature from the perpetual positive feedback. But in fact the warm period (MUCH warmer than now!) in the early part of the last millennium was followed by a steep DROP in temperature, producing the Little Ice Age.
This turnaround could not happen unless it was the sun that was leading the temperature change, not the CO2 levels. It is relevant that sunspot activity almost disappeared prior to and during this cold period. This supports the theory of increased cloud cover caused by increased cosmic ray activity, as an active sun is known to deflect more of these rays from the Earth.

John Bentley, Huntingdon, UK

Phil Davis, you may be right. Unless that is, there are any man made sources of carbon dioxide and other green house gases released into the atmosphere. I wonder, does any one know if there are any man made sources of carbon dioxide, because if there are, we could be in a spot of bother.

D Baird, Swindon, Gloucestershire

The ice core data goes back before the period when human activity introduces CO2into the atmosphere, which is why you get the effect after the temperature rise in those. What is happening now is that we are introducing the CO2, which causes the rise in temperature, which then triggers the further natural release. So we are causing it, and it is being then amplified by this natural release

Ian Simmons, Newcastle Upon Tyne, UK

There is a wealth of data on climate change which can be manipulated to support either the 'naturally-occurring' or 'human activity' theses.

Which is why there's only one way to settle this:

FIGHT!

Mikey, Streatham, UK

Phil Davis: The ice core data covers a period of 650,000 years and tells us what happened before man made any impact on earth and the atmosphere.

The amount of carbon dioxide in the atmosphere today is 30 percent more than the peak level during those 650,000 years. Methane is also much higher than at any time during the same period.

We're in new territory, probably man made.

Ken May, Poole, UK

Quote

"Claim: Ice core data shows that carbon dioxide levels rise after temperatures go up, not before

Fact: This is correct, but climate scientists have a good explanation. There is a substantial feedback effect – initial small rises in temperature lead to substantial release of carbon dioxide from natural reservoirs in the oceans, which then produce much steeper warming later on "

So its not man-made then !!

Phil Davis, Cheltenham, Glos

Let's have more such debate on the disputed 'facts', but from the scientists in the programme, not just a media man. There was a lot more in the programme than this short article covers

Ibnez, Homerton,