"Peter Wilkins" wrote in message
...
On Wed, 9 Nov 2005 11:56:57 -0000, "Alastair McDonald"
k wrote :


Geez Alistair, you really won't let me have my little bit of fun, will
you?

This is not a laughing matter :-(

I was so doubled up laughing that anyone could believe and actually
say that water vapour was an unexpected greenhouse gas that I couldn't
read much further.

What they were saying was that they had under-estimated the effect
of water vapour in their climate models. That means the effects of
AGW will be much worse than those that are currently being predicted.

So they did pin it on mankind after all, although I could be a nit-picker
and say that it's not just CO2!

The climate system is full of positive (bad) and negative (good)
feedbacks, and we do not know exactly how the climate system
will react to us adding CO2 to it. What we don't know is whether
the consequences will be bad or very bad. It is not whether they
will be good or bad, as the skeptics would like to have you think.
What that article is implying is that it is going to be very bad!

But I'm still puzzled - I thought more water vapour in the atmosphere
was a GOODS THING as it means more clouds and reduced solar
insolation. So shouldn't we hurry up and burn more carbon? (sorry,
just joking.... I think....)

It is important to realise that more water vapour in the atmosphere
does not necessarily mean more clouds. Clouds only form when air
cools below its dew point temperature. The cooling is normally
because the air is rising, because of either convection or as it passes
over mountains. Since, what goes up must come down, the amount
of rising air equals the amount of falling air, and so cloud cover tends
to be fixed at a global value of 50%.

The point is that the CO2 will raise temperatures which will cause
more water vapour, which will raise temperatures, which will cause
more water vapour, which will ... But the clouds will not necessarily
increase to compensate.

Thus the climate will heat up until there is a switch in the system which
leads to more clouds. When that happens, the farmers will be taken
by surprise and the world will starve. The paddy fields will dry up,
and the deserts will bloom, but no one is farming them!

And sorry about the delayed response to acknowledge the
correctness of your post: I only just found it. My new newsreader
is inexplicably marking posts to this newsgroup as "read" even
though I have it set as "watch". I can't cope with this new
technology - or perhaps it is just than my newsreader is smarter
than I am. (I see you nodding your head in agreement..)

I don't think your newsreader is smarter than you, but perhaps
the man who wrote it is - Bill Gates. I am pretty sure he is richer
that you anyway. Have you checked the synchronisation
settings by right clicking on the news group name.

Keep smiling and keep posting - I find your posts some of the
most rational and informative in this newsgroup - amongst the
few that are worth reading.

But I can't completely agree with your statement that this
newsgroup is concerned with science, not politics. I do agree
it SHOULD be!

Thanks, I try to keep my posts interesting, sometimes at the cost
of civility :-( Sorry Roger.

It sounds as though you are following this thread on the
alt.global-warming or uk.environment newsgroups which I agree
should not avoid the politics. I am following it on sci.environment
where a few professional scientists post stuff worth reading too!
This probably applies even more to sci.geo.meteorology but
you do get even more dross in along with the pearls in these
big groups.

I noticed recently that your Australian environment minister, a
Campbell, was weakening on global warming. Luckily for Howard
focus on that has now been removed by the discovery of suicide
bombers. Apparently they were using the same methods as
the London bombers, the ones who distracted attention away
from Tony Blair's attempt to get George Bush to sign up to Kyoto
at the Edinburgh G8 meeting. (Well this is going out to
alt.global-warming so why not a little conspiracy theory :-)

Cheers, Alastair.