Speaking of red light jumping......

[James Annan]

Tony Raven wrote:
> James Annan wrote:
>
>>I suggest you back up that with some references, or, since they do not exist, admit that you are
>>wrong. If you want some clues you could start with http://www.wmc.care4free.net/sci/iceage/
>>
>
>
> Thanks for the references. I think the first reference, the Newsweek article from 1975, sums it up
> completely for me.

Very clever. Now try finding a scientist who said it, rather than a journalist looking for a story.

James

 

[Tony Raven]

James Annan wrote:
>
> Very clever. Now try finding a scientist who said it, rather than a journalist looking for
> a story.
>
>

I think any discussion we might have on this can be summarised by the comments made on the website
by Nigel Calder (http://www.wmc.care4free.net/sci/iceage/calder.html), who did the BBC Series/Book
"The weather machine" in the mid '70's and your website author's response which dismisses it all out
of hand. I have to say my recollection coincides with Nigel Calder and a quiet half an hour browsing
New Scientists from the '70's confirmed that view.

There was a general scientific expectation that a "mini ice age" was coming and would have an impact
in the short term as well as the next millennium. Places like Boston and London were going to get
iced over, the droughts and storms of the mid 70's were suggested as the first signs of it
happening. Figures like the head of the Met Office and others were quoted. Ideas such as carbon
blacking the Arctic ice to increase its solar warming were being suggested to counter it. One
article ended with the statement "The time has come to stop arguing about the history and cause of
ice ages and start discussing how our species is going to hold back the next one"

Your website author dismisses it all as non peer reviewed tittle tattle and therefore it can be
completely ignored. That is a point of view he is entitled to but not one I agree with. Others can
make their own minds up.

Tony

 

[James Annan]

Tony Raven wrote:

>
>
> Your website author dismisses it all as non peer reviewed tittle tattle and therefore it can be
> completely ignored. That is a point of view he is entitled to but not one I agree with. Others can
> make their own minds up.

What the website author says (and I agree, having seen the failure of anyone to come up with any
evidence to the contrary) is that no scientists ever made anything that can be remotely considered a
meaningful prediction. At the time, scientists had just discovered that there had been a cycle of
cold and warm periods, with the latter generally lasting about 10,000 years. All they said was that
in this context, we could expect future ice ages, and that remains the scientific consensus even
now, in the absence of human intervention (even back then, the potential for anthropogenic global
warming was also recognised).

In particular, this comment from you earlier:

> Suggest you look back to the sixties and early seventies. The next ice age was every bit as
> imminent then as global warming is today

is certainly false. Any suggestion of a possible future ice age was made in terms of a thousand year
time scale (a figure of 5% probability of it _starting_ within a century was mentioned) and as I've
mentioned above, it was only discussed as a possibility, often predicated on the absence of human
intervention. For you to compare that with the current situation where the changes are almost
certainly already happening, and certainly substantial effects will be obvious in well under a
century (have you seen the recent AGU statement
http://www.agu.org/sci_soc/policy/climate_change_position.html ?), and use it as an excuse for your
head in the sand attitude is risible.

James

 

[Tony Raven]

James Annan wrote:
>
> What the website author says (and I agree, having seen the failure of anyone to come up with any
> evidence to the contrary) is that no scientists ever made anything that can be remotely considered
> a meaningful prediction.
>

I wonder if there is a copy of "The Weather Machine and the Threat of Ice" BBC programme still
around anywhere. It had interviews with many of these scientists about exactly this topic but I
doubt we'll find a copy.

You and Dr Connolley are looking at it second hand, Nigel Calder and I lived through that period,
had a keen interest in it at the time and remember it first hand. The droughts and storms of '75/6
and the exceptional summer of '76 attracted as much speculation about the coming ice age as this
summer's record temperatures did about global warming. Much of the evidence will now be difficult to
find if it still exists at all - the BBC programme with its scientist interviews being just one
example. The fact that it cannot be easily found does not mean the accounts from contemporary
observers are wrong.

Anyway lets again agree to differ before urc starts yawning - sorry too late.

Tony

 

[James Annan]

Tony Raven wrote:

>
> You and Dr Connolley are looking at it second hand, Nigel Calder and I lived through that period,
> had a keen interest in it at the time and remember it first hand.

We are not that young! At least, I am not. I also remember the media stories, although I _was_ a bit
too young to be reading peer-reviewed journal articles.

No-one is denying that a new ice age was suggested as a possibility. But even Nigel Calder, a
journalist looking for a story, could only come up with an estimate of a 5% probability that it
would _start_ within the next century. I bet he would now say that there is a 95% probability that
the anthropogenic warming has already started.

Even back then, the global warming effect of CO2 was (somewhat) understood (its strength was rather
underestimated IIRC), but so was the cooling effect of dust, so after a few cold winters (and with
the ever-present threat of a nuclear winter) it is hardly surprising that some attention was paid to
the cooling threat. But the scientists were quite clear that at that time, there was a great deal of
uncertainty - this was a very young branch of science. As you have seen, none of your imagined
predictions of an imminent ice age actually got through peer-review, all that remains is a few old
chip-wrappers...

The attempts of the 'sceptics' to equate this past discussion of the _possibility_ of an eventual
ice age, with the current consensus about the immediate threat, and claim that the scientists have
changed their tune and therefore must be scaremongering and wrong, is barrel-scraping of the
highest order.

James

 

[Tony Raven]

James Annan wrote:
>
> I bet he would now say that there is a 95% probability that the anthropogenic warming has already
> started.
>

I doubt it. IIRC even the IPCC only class the warming being anthropogenic as "likely" where likely
is defined as 66-90% chance. The magnitude and character of natural climate variability is one of
the key uncertainties they list. A friend who chairs some of the major international committees on
climate change says: that the earth is warming up is now beyond doubt, whether it is due to natural
variation or man's activity is an open question but the precautionary principle of restricting CO2
emissions should be used until we know the answer.

Tony

 

[James Annan]

Tony Raven wrote:
> James Annan wrote:
>
>>I bet he would now say that there is a 95% probability that the anthropogenic warming has already
>>started.
>>
>
>
> I doubt it. IIRC even the IPCC only class the warming being anthropogenic as "likely" where likely
> is defined as 66-90% chance.

The IPCC Third Assessment Report (unless you are referring to anything more recent) was written
several years ago, and undoubtedly lags the current scientific consensus. Certainly since that
report was written, plenty more evidence has been published, and it overwhelmingly points to that
confidence being revised upwards (eg this ref to Barnett mentions the 95% figure:
http://fire.pppl.gov/GCC_Science_Kerr_Barnett.html). I also refer you again to the AGU statement,
which says that the scientific evidence "strongly indicates" a non-natural cause.

> The magnitude and character of natural climate variability is one of the key uncertainties
> they list.

It certainly is a source of uncertainty, but no-one has managed to get any model to simulate the
recent substantial warming (in particular, the warming of the world's ocean which has soaked up
about 16X10^22J over the last 40 years), without adding a substantial anthropogenic forcing. Once
they add the anthropogenic effects, the simulation is remarkably good.

> A friend who chairs some of the major international committees on climate change says: that the
> earth is warming up is now beyond doubt, whether it is due to natural variation or man's activity
> is an open question but the precautionary principle of restricting CO2 emissions should be used
> until we know the answer.

That's a rather different approach from your "wait and see".

James

 

[Just Zis Guy]

On Sat, 20 Dec 2003 01:05:50 -0000, "Tony Raven"
<[email protected]> wrote:

>A friend who chairs some of the major international committees on climate change says: that the
>earth is warming up is now beyond doubt, whether it is due to natural variation or man's activity
>is an open question but the precautionary principle of restricting CO2 emissions should be used
>until we know the answer.

That is the most reasonable conclusion, for sure. The Global Climate Coalition's alternative of no
change until we can prove beyond doubt that global warming is due to human factors is insane, IMO.
The proof could come too late.

Guy
===
May contain traces of irony. Contents liable to settle after posting.
http://chapmancentral.demon.co.uk

 

[Alan Braggins]

Just zis Guy, you know? wrote:
>On Sat, 20 Dec 2003 01:05:50 -0000, "Tony Raven" <[email protected]> wrote:
>
>>A friend who chairs some of the major international committees on climate change says: that the
>>earth is warming up is now beyond doubt, whether it is due to natural variation or man's activity
>>is an open question but the precautionary principle of restricting CO2 emissions should be used
>>until we know the answer.
>
>That is the most reasonable conclusion, for sure. The Global Climate Coalition's alternative of no
>change until we can prove beyond doubt that global warming is due to human factors is insane, IMO.
>The proof could come too late.

What I've never understood is where they get the idea that if global warming isn't due to human
factors then we shouldn't bother trying do anything about it. I haven't seen anyone argue that if it
isn't due to human factors then any measures we take will be useless, it just seems to be a case of
human caused global warming might be bad but if it's natural, then it must be ok.

 

[Tony Raven]

Alan Braggins wrote:
>
> What I've never understood is where they get the idea that if global warming isn't due to human
> factors then we shouldn't bother trying do anything about it.

The question is what do you do if its natural and not human. If human CO2 emissions are not the
cause, cutting human CO2 emission will not solve the problem. In fact pumping more particulates into
the atmosphere could be one way of reducing warming.

In reality there will never be a control experiment to compare what would have happened if... And
nobody knows enough yet to know what the consequences of any particular action will be so all you
can do is make your choice, roll the dice and hope it was a good choice

Tony

 

[James Annan]

Alan Braggins wrote:

> What I've never understood is where they get the idea that if global warming isn't due to human
> factors then we shouldn't bother trying do anything about it. I haven't seen anyone argue that if
> it isn't due to human factors then any measures we take will be useless, it just seems to be a
> case of human caused global warming might be bad but if it's natural, then it must be ok.

It's because the attribution to human factors is closely tied up with the understanding and ability
to do anything useful in mitigation. If it _isn't_ due to human factors, then no-one has much of a
clue as to what else it could be due to, or what we could possibly do about it.

James

 

[James Annan]

"Tony Raven" <[email protected]> wrote in message news:<[email protected]>...
> Alan Braggins wrote:
> >
> > What I've never understood is where they get the idea that if global warming isn't due to human
> > factors then we shouldn't bother trying do anything about it.
>
> The question is what do you do if its natural and not human. If human CO2 emissions are not the
> cause, cutting human CO2 emission will not solve the problem. In fact pumping more particulates
> into the atmosphere could be one way of reducing warming.

Hallelujah, we more-or-less agree about something. Well, I guess it had to happen eventually. Makes
me feel all Christmassy.

> And nobody knows enough yet to know what the consequences of any particular action will be

It's disengenuous to imply that there ever will be a time when we will be able to predict the
consenquences, and that we currently cannot do so. There is no threshold to pass, all that happens
is that the accuracy of the predictions should generally increase over time.

> so all you can do is make your choice, roll the dice and hope it was a good choice

One can (and should) always try to make the best decision based upon what information is available.
Wait-and-see is effectively a deliberate decision that the best action is to do nothing.

James