[another_someone]

The attached link is a to Channel 4 Dispatches documentary entited "The Global Warming Swindle" (their words, not mine).

http://video.google.com/videoplay?docid=4340135300469846467&q=global%2Bwarming%2Bswindle

or

http://video.google.com/videoplay?docid=-4520665474899458831&q=global%2Bwarming%2Bswindle

Clearly, all media is populist to some exent, and I do not claim they do not hype in their onw way just as the other side do, but it is nonetheless an interesting balance.

[paul.fr]

*picks keyboard up and throws it out the window*   []

well i am having trouble watching the movie, i am up to 20 minutes and it has frozen. i will have another try at watching it over the weekend.

Although, 20 minutes in and it seems far from balanced. An ex-editor of New Scientist, please tell us why you are an ex-editor? He is moaning about the IPCC and their policies. The new scientist has for years gone along with the theory of climate change. was he the editor during those times?

Childish animation...Lord Lawson, Lord Lawson...my god even as a conservative i would be hard push to take him seriously.

Oh jeremy paxman being his obnoxious self....this is how paxman interviews, and he is damn good at it. i would say that clip was there to try and knock the BBC and a bit of jealousy on C4's part as they have nobody of the same calibre as paxman.

[another_someone]

I did make it clear that I agree it is not balanced, but then neither are any of the people on the other side.

The fact that Environmentalism has become a religion, where being balanced is not acceptable - you are either one of us, or you must be against us - is part of the big problem.

I think it does have a number of interesting things to say (OK, most of them I already knew, a few I did not); but I would agree, one should never accept as gospel anything in this without checking it out with other sources.

The problem is, people need to be checking the data more critically, and if this causes pause for thought, then that is good - but you should no more accept their religious perspective than you should accept the Environmentalists religious doctrine.

I have to say that when they have to stoop to interspersing so many images of pretty young things in bikinis, it does not add to their credibility.

As I said, the main point to me is to start suggesting that at last having a contrary opinion is no longer taboo.

[another_someone]

Although, 20 minutes in and it seems far from balanced. An ex-editor of New Scientist, please tell us why you are an ex-editor?

Maybe his date of birth - 1931 - might give a clue.

In fact, he left New Scientist in 1966, long before the global warming debate.

http://en.wikipedia.org/wiki/Nigel_Calder

He is moaning about the IPCC and their policies. The new scientist has for years gone along with the theory of climate change. was he the editor during those times?

Clearly, no.

Childish animation...Lord Lawson, Lord Lawson...my god even as a conservative i would be hard push to take him seriously.

Since it is clear that you are a post Thatcherite Conservative, I suspect there are not many of that era you would take seriously.

No, I would not regard Lord Lawson as meaningful in scientific terms (he is a politician, not a scientist), but in terms of understanding the political thinking surrounding the issue, I see no reason to give him any less credit than any other politician.

Oh jeremy paxman being his obnoxious self....this is how paxman interviews, and he is damn good at it. i would say that clip was there to try and knock the BBC and a bit of jealousy on C4's part as they have nobody of the same calibre as paxman.

This rather assumes that editorial control of the documentary was in the hands of Channel 4 managers rather than professional editor who do documentaries for a living.

Ofcourse the Paxman clip was there for effect, as a lot of the rest of the clips were - it was there because Paxman can be obnoxious, and intimidating, and it was intended to indicate how much intimidation is used to force the Environmental issue (but as you say, Paxman is a bully in any context, and not particularly only with regard to the Environmental issues).

[another_someone]

Another set of videos, from which a lot of the material for the Channel 4 documentary seems to have been taken (a lot of the same scientists are interviewed, although there are a few that are not in the Channel 4 documentary, and it does not include the political interviews that are in the Channel 4 documentary - and it feels no need to include bikini clad women).

http://www.friendsofscience.org/index.php?ide=3

There is no doubt that this too is a political agenda, although one that puts scientists in the foreground - alas, it is impossible to deal with climate issues without it becoming political.

The political agenda is highlighted at:

http://www.friendsofscience.org/index.php

[paul.fr]

The fact that Environmentalism has become a religion, where being balanced is not acceptable - you are either one of us, or you must be against us - is part of the big problem.

Agreed, it would be nice if next week they showed the case for climate change. This would give the viewer the chance to look at both sides.

I have to say that when they have to stoop to interspersing so many images of pretty young things in bikinis, it does not add to their credibility.

Now i must watch the whole episode  []

[paul.fr]

Since it is clear that you are a post Thatcherite Conservative, I suspect there are not many of that era you would take seriously.

Not really, My previous comments about being weakened by Ms T were not against her. My point was that she was such a strong leader that we have suffered ever since because nobody has come close to being the leader that she once was.

True she was not well loved in this country from the middle of the 80's onwards, but she was feared and reveared in Europe and the rest of the world.

There are many Thantcherite MP's that i like, Ken Clarke for one. I had him picked for the new leader...but alas it was not to be.

No, I would not regard Lord Lawson as meaningful in scientific terms (he is a politician, not a scientist), but in terms of understanding the political thinking surrounding the issue, I see no reason to give him any less credit than any other politician.

But Lawson was quoting from a report made in the 80's (now i had a lot of buffering and so missed bit and could be wrong on the year/decade. how is that credible now? That's why i did not think it relevant to have him on.

This rather assumes that editorial control of the documentary was in the hands of Channel 4 managers rather than professional editor who do documentaries for a living.

I would expect that C4 play some part in the nature of programmes produced, and MAY put forward their views on the direction of the programmes. Afterall C4 are all about courting controversy.

Of course the Paxman clip was there for effect, as a lot of the rest of the clips were - it was there because Paxman can be obnoxious, and intimidating, and it was intended to indicate how much intimidation is used to force the Environmental issue (but as you say, Paxman is a bully in any context, and not particularly only with regard to the Environmental issues).

But don't you just love the interviewing technique of the man. No matter what you think of him personally, you have to admit he is not one of the breed of interviewers that ask lame questions or let the interviewee off lightly.....plus he is not dumbing down.

[Cut Chemist]

That is an interesting documentary.  I watched the entire thing.  It raises some interesting ideas. 

It does make sense that global warming or climate change in general wouldn't be directly caused by man.  Man has only been around for a fraction of a second in comparison with the age of the earth, and the climate has been changing since the earth was formed. 

It also makes sense that the sun and the oceans would play a huge role in the climate of the earth ...  They would have a much much greater effect than anything man could dish out.  So, the idea that man is not responsible for "global warming" is very believable.

The idea that amount of CO2 and water vapor being absorbed or released by the oceans would be dependent on the average temperature is basic physical chemistry (gas laws.)  And it would make sense that the earth and its oceans would have a way of absorbing minor changes that we cause to its atmosphere.

I haven't seen "An Inconvienient Truth" (Al Gore's movie) but I I find it hard to believe that the scientists that Al Gore employed or cited in his movie would have overlooked the inconsistencies that were exposed in this film.  It sounds like he might have twisted the data ... shifted one graph over a few months or years.  I would need to do research to know which is correct, but this documentary seems to me like its more from the scientific community than a political adgenda.  Does anyone study this here??  Which interpretation is correct???

One of the issues that I have with this documentary is the fact that they act like the only issue that greenpeace and the other environmental organizations are supporting is "global warming."  They don't mention pollution, the ozone layer, endangered species, the rainforest, recycling, or any other issues or ideals that these agencies support or condemn.  (I think the IPCC is only interested in climate change, and so that's why in the beginning they only focus on them,)  But at the end of the show they attack these other agencies as being "protest groups" or something to that affect, when in fact they didn't prove any of their other issues or ideals wrong. 
My main objection is pollution, and the fact that coal is a much dirtier source of energy.  "Global Warming" is not the only reason that we don't want every villiage in Africa to build a coal powered electrical plant.  Granted today we have new technology that will greatly reduce emissions ... But the argument is not solely based on global warming, and neither are most of the other arguments.

Does global warming have anyting to do with the ozone layer???  (I'm not up on environmental science and I was just wondering...)

I think its sad that science is governed by politics, but as a member of academia in the U.S. I can vouch for the fact that your research has to be funded, and you have to go where the money is.  Politicians pay for work that says what they want to hear, and going against the main stream is a good way to go broke.

All in all, it was a very interesting film, and I'd like to hear what others thought about it.  Are there any environmental science majors out there who got their feelings hurt, or can "prove them wrong??" 

PS:  Great topic another someone!!

[paul.fr]

I haven't seen "An Inconvienient Truth" (Al Gore's movie) but I I find it hard to believe that the scientists that Al Gore employed or cited in his movie would have overlooked the inconsistencies that were exposed in this film.  It sounds like he might have twisted the data ... shifted one graph over a few months or years.  I would need to do research to know which is correct, but this documentary seems to me like its more from the scientific community than a political adgenda.  Does anyone study this here??  Which interpretation is correct???

So not having seen the film you are qualified to attack it! Now what evidence do you have that the scientists were employed by Al Gore? Could they not have been concerned scientists that saw the film as a medium to get their point accross? Have you researched the "inconsistencies exposed in this film" and concluded that they are infact inconsistancies? or could they be what a group of people believe to be incosistancies? it is all about propaganda, it is up to the individual to do the research and come to their own conclusions as to what they believe. Now having watched what one side has to say you may wish to watch Al Gore's film and weight the balences and make as best you can an informed decision on what you have seen from both sides.

One of the issues that I have with this documentary is the fact that they act like the only issue that greenpeace and the other environmental organizations are supporting is "global warming."  They don't mention pollution, the ozone layer, endangered species, the rainforest, recycling, or any other issues or ideals that these agencies support or condemn.  (I think the IPCC is only interested in climate change, and so that's why in the beginning they only focus on them,)  But at the end of the show they attack these other agencies as being "protest groups" or something to that affect, when in fact they didn't prove any of their other issues or ideals wrong. 
My main objection is pollution, and the fact that coal is a much dirtier source of energy.  "Global Warming" is not the only reason that we don't want every villiage in Africa to build a coal powered electrical plant.  Granted today we have new technology that will greatly reduce emissions ... But the argument is not solely based on global warming, and neither are most of the other arguments.

But issues such as pollution, the ozone layer, endangered species, the rainforest and recycling are all impacted up on by climate change - we do not use global warming as it is not strictly correct, there will also be global cooling.

I think its sad that science is governed by politics, but as a member of academia in the U.S. I can vouch for the fact that your research has to be funded, and you have to go where the money is.  Politicians pay for work that says what they want to hear, and going against the main stream is a good way to go broke.

But you do not have to "toe the party line", go out and get independant funding. As it happens much research in to climate change was hampered in the US for the reason you state....the Bush Government, did not want the research done and held back funding. this did not stop the scientists getting alternative funding, granted it did make it harder.

[another_someone]

Not really, My previous comments about being weakened by Ms T were not against her. My point was that she was such a strong leader that we have suffered ever since because nobody has come close to being the leader that she once was.

I have to be careful how far we go down this road, not because I would have any qualms personally about discussing the issues, but because I have to remember that this is a science forum rather than a political one.

What I am going to do is separate this part of my replay to a separate message, and if you choose to respond to it, I will split the thread so that we don't get the science threads polluted with party politics.

I don't think it is so much a case that the Conservatives have nobody to compare with Thatcher, it is rather that strong people cannot thrive under a strong regime – strong leaders come forward during periods of a political vacuum, when there is nobody strong enough to suppress them.  Thus you almost never find a strong leader following on from another strong leader (it shall be interesting to see how the Blair/Brown succession turns out, since it is conceivable that this may be an exception to that rule, but many have said that Blair's premiership was really more a double act anyway, more in the mould of Thatcher/Whitelaw than the lone Thatcher era – but then, I always believed the Thatcher/Whitelaw team was a much better balance team, and Thatcher largely lost her way with the loss of Whitelaw).

True she was not well loved in this country from the middle of the 80's onwards, but she was feared and reveared in Europe and the rest of the world.

Not sure that being feared is a good thing, but I think the one aspect that even her detractors accept is that she was honest – she did and said what she believed, for better or for worse, and did not try and dress it up as something else (OK, maybe history will show otherwise, but that is what was perceived at the time).

Of course the Paxman clip was there for effect, as a lot of the rest of the clips were - it was there because Paxman can be obnoxious, and intimidating, and it was intended to indicate how much intimidation is used to force the Environmental issue (but as you say, Paxman is a bully in any context, and not particularly only with regard to the Environmental issues).

But don't you just love the interviewing technique of the man. No matter what you think of him personally, you have to admit he is not one of the breed of interviewers that ask lame questions or let the interviewee off lightly.....plus he is not dumbing down.

No, I am afraid I do not find bullying to be entertaining.  I would much rather he dealt in facts than specialised in simply making people uncomfortable for the sake of it.  Clearly,m if the facts make people uncomfortable, then so be it, but often a lot more real information can be obtained by a more seductive approach than be outright bullying.

[another_someone]

But Lawson was quoting from a report made in the 80's (now i had a lot of buffering and so missed bit and could be wrong on the year/decade. how is that credible now? That's why i did not think it relevant to have him on.

Lawson was commenting on two issue.

Firstly, he was commenting upon why he believed the Thatcher Government originally jumped on the global warming bandwagon.  This was a political observation rather than a scientific one, and did pertain the the early years of the global warming debate in the 1980s.

Secondly, he was commenting upon his own role while in the House of Lords on a committee looking at the issue of global warming.

One report in which he is named (amongst others) is a report published in 2005:

http://www.parliament.uk/parliamentary_committees/lords_press_notices/pn060705ea.cfm
http://en.wikipedia.org/wiki/Nigel_Lawson

In 2005, along with six others, Lawson wrote a letter to The Times criticising the Kyoto Protocol and claiming that there were substantial scientific uncertainties surrounding climate change [1], he also wrote on the same subject in the November 2005 issue of Prospect magazine. Shortly afterwards, the House of Lords Economics Committee of which Lawson was a member, undertook an inquiry into the topic[1], which produced a report consistent with the arguments of Lawson's letter[citation needed].
In response, the British government established the Stern Review, an inquiry undertaken by the UK Treasury and headed by Sir Nicholas Stern. The Stern Review found that the potential costs of climate change far exceeded the costs of a program to stabilise the climate.
Lawson's recent lecture to the Centre for Policy Studies think-tank, published 1 November 2006 [2] criticises the Stern Review and proposes what it describes as a rational approach, advocating adaptation to changes in global climate, rather than attempting to mitigate or reverse it.
Lawson also contributed to the 2007 documentary film The Great Global Warming Swindle.

[another_someone]

I haven't seen "An Inconvienient Truth" (Al Gore's movie) but I I find it hard to believe that the scientists that Al Gore employed or cited in his movie would have overlooked the inconsistencies that were exposed in this film.  It sounds like he might have twisted the data ... shifted one graph over a few months or years.  I would need to do research to know which is correct, but this documentary seems to me like its more from the scientific community than a political adgenda.  Does anyone study this here??  Which interpretation is correct???

So not having seen the film you are qualified to attack it! Now what evidence do you have that the scientists were employed by Al Gore? Could they not have been concerned scientists that saw the film as a medium to get their point accross? Have you researched the "inconsistencies exposed in this film" and concluded that they are infact inconsistancies? or could they be what a group of people believe to be incosistancies? it is all about propaganda, it is up to the individual to do the research and come to their own conclusions as to what they believe. Now having watched what one side has to say you may wish to watch Al Gore's film and weight the balences and make as best you can an informed decision on what you have seen from both sides.

What Cut Chemist did say was that he does need to do the research – which is totally consistent with what you have said.  He put forward some provisional scenarios that he believed were true (unfortunately, I do not agree that scientists could not have overlooked inconvenient data – scientists always overlooks data.  Part of science is trying to judge what in the data is noise and what is meaningful information, and often scientists cannot agree amongst themselves about which is which – it is often just a matter of judgement, and it is not until very much later that one sees what really was significant in the dataset.

My own judgement is that both Al Gore's “An Inconvenient Truth” and Martin Durkin's “The Great Global Warming Swindle” are propaganda made for public consumption, and as such, both are more concerned about pulling on the heart strings than they are with scientific rigour (it is probably telling that Al Gore's film got an Oscar, but not a Nobel Prize – it tells you which constituency he was addressing).  In both cases, I think what is valuable is the ideas proposed, and not the conclusions drawn (anyway, in my opinion, one should always draw one's own conclusion on anything, and never accept on faith anybody else's conclusion).  To my mind,  Martin Durkin's has greater value only because it runs counter to the prevailing popular thinking, and so draws more new ideas into the public arena (although many of those ideas have been talked about in isolation by various members of the scientific community).  The reality is that neither film is likely to really change many people's minds – neither are rigorous enough for that, and in both cases the constituency they are trying to talk to would probably not be able follow the rigour the scientific community would expect).

One of the issues that I have with this documentary is the fact that they act like the only issue that greenpeace and the other environmental organizations are supporting is "global warming."  They don't mention pollution, the ozone layer, endangered species, the rainforest, recycling, or any other issues or ideals that these agencies support or condemn.  (I think the IPCC is only interested in climate change, and so that's why in the beginning they only focus on them,)  But at the end of the show they attack these other agencies as being "protest groups" or something to that affect, when in fact they didn't prove any of their other issues or ideals wrong. 
My main objection is pollution, and the fact that coal is a much dirtier source of energy.  "Global Warming" is not the only reason that we don't want every villiage in Africa to build a coal powered electrical plant.  Granted today we have new technology that will greatly reduce emissions ... But the argument is not solely based on global warming, and neither are most of the other arguments.

But issues such as pollution, the ozone layer, endangered species, the rainforest and recycling are all impacted up on by climate change - we do not use global warming as it is not strictly correct, there will also be global cooling.

Sorry, but none of the arguments concerning CO₂ refer to global cooling.  There has been some debate about local cooling, but that is a different matter.

In any case, nobody is disputing climate change, the dispute is only whether it is man made (the argument being that the climate always has, and always will, change – and nothing you can do will stop that – and worse still, if you were to successfully stop the climate from changing, you would have destroyed the natural dynamics of the planet).

As for the arguments for pollution (and this is a major ongoing issue in India and China as they are rapidly industrialising – would you have them remain in their historic poverty?) is that 'pollution' is only bad if there is a lot of it.  Nature can deal with a fair amount of waste – it always has done, and often what we consider to be waste can even be beneficial to some other organism.  The problem only happens when things get scaled up so much that the waste over powers the natural processes.

But you do not have to "toe the party line", go out and get independant funding. As it happens much research in to climate change was hampered in the US for the reason you state....the Bush Government, did not want the research done and held back funding. this did not stop the scientists getting alternative funding, granted it did make it harder.

Independent of what?

In the 19^th century and before, science was often carried out by gentlemen scientists of independent means, but that is no longer the case, and whomsoever pays you to do science will do so for their own reasons, and unless your science happens to satisfy their reasons, they will not pay.

Money is presently mostly in the hands of governments, intergovernmental organisations, and multinational industries – they are the only ones with the funds to pay for a lot of science.  Which of those sources would you regard as 'independent funding'?

The point is that it really does not matter who is paying you, but most science is problem driven (whether it is a cure for cancer, or global warming), and scientists (like engineers) are being paid to solve a problem, and if they come back and say there is no problem, then it will be difficult to justify continuing to pay them.

[BillJx]

The point is that it really does not matter who is paying you, but most science is problem driven (whether it is a cure for cancer, or global warming), and scientists (like engineers) are being paid to solve a problem, and if they come back and say there is no problem, then it will be difficult to justify continuing to pay them.

There is no shortage of newspaper columnists who describe anthropogenic global warming as an unproven idea.  There is no shortage of internet posters who insist on alternative explanations.  But there is a serious shortage of peer-reviewed papers by professional, accredited climatologists who doubt that climate change is real, is serious, and is caused by greenhouse gases.  Are you actually suggesting that they are making it up to get funding?

[another_someone]

The point is that it really does not matter who is paying you, but most science is problem driven (whether it is a cure for cancer, or global warming), and scientists (like engineers) are being paid to solve a problem, and if they come back and say there is no problem, then it will be difficult to justify continuing to pay them.

There is no shortage of newspaper columnists who describe anthropogenic global warming as an unproven idea.  There is no shortage of internet posters who insist on alternative explanations.  But there is a serious shortage of peer-reviewed papers by professional, accredited climatologists who doubt that climate change is real, is serious, and is caused by greenhouse gases.  Are you actually suggesting that they are making it up to get funding?

No, I am not suggesting that they are all making it up just to get funding (although it is not unheard of for apparently reputable scientists to fiddle the figures - but I would believe those still only to represent a minority), but what I am suggesting is that those who do not think there is a problem will not get funded, so they will not have the money to do the work, so they will not have any material to publish.

There is also some question marks over the peer review process itself, since it tends to be a process that is designed to reinforce the concensus and will always make it more difficult (although that is not the same as saying it is impossible) for those who wish to publish something that undermines the consensus to have a voice.

But the most serious problem remains that a research scientist without a research grant cannot have anything to publish.

But aside from the funding issue, there is also a very human problem.  Most decent people (be they scientists or anyone else) want to get involved in projects they believe in.  Those scientists who simply don't believe in the whole global warming issue will naturally simply not be motivated to become involved in that line of research.

[Mjhavok]

Hi All,

For the past few years I have basically took it for granted that global warming is happening. After doing more reading recently and talking to someone who is really interested in this and does a lot of research (on the net) I am unsure.

I feel that humanity pumping CO2 and other greenhouse gases into the atmosphere must be doing some damage but is it as bad as feared.

My friend said that Al Gore is a lay person and gets a lot wrong in his documentary. For instance ethanol and solar power take so much energy to make that they are just causing as much pollution. I also read that earth may be going through its natural cycle, ice age, warm up etc. What is the truth in this?

So.. My question is what is the current research (if you know) and is there a consensus. Could you direct me to any articles regarding this.

Thank You

Steven

[another_someone]

Hi All,

For the past few years I have basically took it for granted that global warming is happening. After doing more reading recently and talking to someone who is really interested in this and does a lot of research (on the net) I am unsure.

I feel that humanity pumping CO2 and other greenhouse gases into the atmosphere must be doing some damage but is it as bad as feared.

My friend said that Al Gore is a lay person and gets a lot wrong in his documentary. For instance ethanol and solar power take so much energy to make that they are just causing as much pollution. I also read that earth may be going through its natural cycle, ice age, warm up etc. What is the truth in this?

So.. My question is what is the current research (if you know) and is there a consensus. Could you direct me to any articles regarding this.

Thank You

Steven

There are three separate questions -

1) Is global warming happening?

2) Is the greenhouse effect having an impact on global warming?

3) Is anthropogenic CO₂ having an impact on global warming.

As I understand it, the dominant opinion is that the answer to all three questions is yes; but the data is far from unambiguous to any one of those questions, and there is nothing like a consensus.

In general, most people suggest that the answer to question 1 is yes, but they cannot agree even then about time-scales, and the implications of it.  Many people who claim the answer to question 3 is no, point to the evidence that global warming has been happening since the 17^th century, and thus before the advent of the industrial revolution, and that there was also a warm period in the middle ages, the period that allowed the Vikings to colonise Greenland.  Yet some people who argue the answer to 3 is yes, actually claim there were no historic cycles of temperature, or that they were only very slight, and that it only happened that their were local variations in temperatures that happened in those areas where human civilisation was literate and able to record it, and where we don't have unambiguous human records, the global temperatures were behaving differently.

There are also those who claim that global temperature in the third quarter of the 20^th was actually falling, before starting to rise again.

So, as you can see, one cannot even have consensus about when the world's temperature is rising or falling, so what hope is there of consensus about the causes of it.

What is clear is that the topic is now highly politicised, and that politicians are used to taking a rather casual approach to accurate truths, and there is increasing friction between the scientific community and the politicians, as the scientists are becoming increasingly concerned that they will get blamed for the political interpretations of their data.

The problem is that the political community wants answers now, and if all else fails, they will make them up as they go along.  Much of the reputable scientific community is concerned that they actually don't have any real answers, just a lot of ambiguous data, and some working hypothesis that may have to be substantially modified as new data is analysed.

The problem is, the politicisation of the data may end up discrediting even the good science, and the political certainties turn out to be scientific gobbledygook.

I have my own beliefs in the matter (predominantly, that global warming is real, but that it is not caused by CO₂, and any influence that humans have on it is slight, and probably more to do with a reduction in global dimming than with any increase in CO₂); but as I said, I am not so naïve as to pretend that unambiguous science based answers exist on any side of the argument.

Unfortunately, a lot of people take the attitude that if we don't have an answer, then we must jump to one conclusion or the other.  Alternatively, they make the naïve assumption that reducing CO₂ is a zero cost option, so we should do it as a precautionary action even if we ultimately gain zero benefit out of it.  Ofcourse, as politicians start to talk about the actual mechanics of reducing CO₂, people start waking up to the fact that it is anything but a zero cost option.

[Mjhavok]

Cheers George.

[WylieE]

Hi Steven,
  I'll jump into the den this time. . .
First, I do not like the term "global warming" I think it is too misleading.  I think global climate change is more appropriate (and safer).
 I think the recent conference on climate change (ICCC) was pretty clear that climate change is occurring and it is likely caused by human activity.  I'll look up the link when I get back to work.
 From the US, the AAAS has issued their statement on global warming:
http://www.aaas.org/news/press_room/climate_change/mtg_200702/aaas_climate_statement.pdf
the first line says most of it. . .
"The scientific evidence is clear: global climate change caused by human activities is occurring now, and it is a growing threat to society."

Personally, I think Al Gore's movie was one of the worse things that could have happened to the debate and I agree with your friend on that point. 

How much ethanol and solar energy cost depend on the assumptions that are made AND if they are economical depends on how much oil costs.  But that is different than how much they contribute to pollution. 

Well, that's a start, I'm sure you will get a lot of responses on this one.
Colleen

[another_someone]

I think the recent conference on climate change (ICCC) was pretty clear that climate change is occurring and it is likely caused by human activity.

That it is clear that climate is changing says nothing that it not self evident.  That we cannot even use the term 'global warming' just shows how ambiguous the nature of the change is.

The moment you have to say something is 'likely' to be true, this somewhat undermines the notion the it is clear that it is true.

That statement therefore juxtaposes two different issues, one of which is self evidently true, and the other is at best considered to be 'likely' to be true, and then tries to blur the distinction between the two.

Furthermore, even insofar as the statement is made, it does not even include reference to CO₂, but merely allows people to assume that is what they are talking about.

"The scientific evidence is clear: global climate change caused by human activities is occurring now, and it is a growing threat to society."

So what is 'evidence'.  Science is not a court of law – something is either true or it is false (OK, you might say that all scientific proof is provisional upon further evidence to the contrary, but it is clear from this statement that they are not even willing to commit to suggesting that such provisional proof exists).

As for being a “growing threat to society” - what is this supposed to mean.  Which society?

Clearly, all climate change has an impact upon the status quo (hence, as the weather warmed during the early middle ages, it allowed the Vikings to colonise areas they could not previously colonise, and once the weather started cooling again, they lost those colonies – so, yes, you could well argue that climate change had an influence, and even posed a threat, to Viking society – does that mean that human kind could, or should, have done anything to stop the climate from changing?).

Generally, global cooling presents more of a threat than global warming, but any change in climate, of whatever nature, will always cause upheaval for human society.  Have we now become so inflexible as a species that we can no longer adapt to changes in climate?

In fact, maybe the most telling part of all of this is that these statements are made, not by front line researchers, but by committees.  I am not saying that there are not front line researchers who would not say this – in fact, I have no doubt there are individual from line researchers who would be far more forceful in their assessment; but the committee then has to balance that against front line researchers who would say the opposite, so the committees come up with anodyne statements that state the obvious with certainty (i.e. that the weather changes, and that an uncertain tomorrow can always be regarded as a threat to the society of today), and hedges the rest with 'likely' and 'evidence', while avoiding saying anything is truly known as certain about any of the controversial stuff.

[WylieE]

OK, so I wasn't going to respond today (it's getting too late)
but I noticed a typo in my post:

It should be the IPCC- not ICCC- here is the link to their summary (the full report will be published later this year).
http://www.ipcc.ch/SPM2feb07.pdf

They provide references for their points, you can follow them if you would like further scientific evidence.

The moment you have to say something is 'likely' to be true, this somewhat undermines the notion the it is clear that it is true.

They use the term "very likely" to be caused by human activity.
They define "likely" as 66-90% probably
and "very likely" as >90%

Furthermore, even insofar as the statement is made, it does not even include reference to CO₂, but merely allows people to assume that is what they are talking about.

They do have a large section on the role that CO₂ plays in the IPCC report.

In fact, maybe the most telling part of all of this is that these statements are made, not by front line researchers, but by committees.

I would certainly consider the AAAS front line researchers (at least in the US).

If anyone is interested in more evidence, I would recommend the IPCC's site:
http://www.ipcc.ch/

They also explain who is involved in the IPCC and the contribution of "front line" researchers to the reports.

Colleen