Comments on: Grapevine: Mann to testify on 27th July

By: Peter Hearnden

Peter Hearnden — Thu, 27 Jul 2006 20:03:43 +0000

#158

Actually I’m in fair agreement with him. I think ‘highly suggestive of a detectable human influence on climate’ means just that, and that ‘At roughly one century, the latter is too short to allow unambiguous attribution of changes to human influences’- is also ‘right’, if one knows what unambiguous means, though I’d like to know how you warm a planet by .6C+ using known forcing and excluding any resulting from our actions. As I understand it only with anthro forcing do the figures add up.

But, for most here I suspect 3C warming by 2100 wouldn’t be unambiguous enough…

By: Peter Hearnden

Peter Hearnden — Thu, 27 Jul 2006 19:49:37 +0000

Re #157, yup, of course!

#157, no, sorry, I was thinking potentially 2-3C. So so far, I concurr, not much, less than ‘~1%’, not a cooling.

By: Dave B

Dave B — Thu, 27 Jul 2006 17:19:03 +0000

peter, #156, etc., you wrote:

“start from absolute zero, add a degree or two background heat, add ~250C for the effect of the sun, ~33C for ghg’s and ~2-3C on top of that for AGW”

that is why i was looking for definitions. my understanding of total measured warming in the 20th century is 0.6 deg C.

so if “A” GW is 2-3 deg C, but actual warming was only 0.6 deg C… then using your numbers, we should have been cooling?

By: Geoff

Geoff — Thu, 27 Jul 2006 15:33:55 +0000

Re #154 – Peter, perhaps you’d like to consider the words of a rather well-known professor (from the year 2000):

“Conventional approaches to understanding the factors underlying the recent warming have involved complex numerical models of the combined ocean-atmosphere system. Although highly suggestive of a detectable human influence on climate, these studies have been limited by intrinsic uncertainties in comparing model-predicted climate change patterns with the instrumental climate record. At roughly one century, the latter is too short to allow unambiguous attribution of changes to human influences”.

He does not go on to specify how many additional years of instrumental record are needed, but he would seem to be on record that we are not there yet.

By: fFreddy

fFreddy — Thu, 27 Jul 2006 09:27:49 +0000

Re #153 et al, Peter Hearnden
Peter, I’d guess that you were trying to use the “less than” sign. The blog interprets this as the beginning of a tag, and gets unhappy if it isn’t folowed by some HTML.
You can make it do a “less than” with the following four characters: & l t ; (remove all the spaces).

By: Peter Hearnden

Peter Hearnden — Thu, 27 Jul 2006 09:18:12 +0000

I give up…

By: Peter Hearnden

Peter Hearnden — Thu, 27 Jul 2006 09:17:33 +0000

Re#153, humm, where did the rest go?

Ok, continues:’

By: Peter Hearnden

Peter Hearnden — Thu, 27 Jul 2006 09:08:12 +0000

#152

It’s true, it is on the Warwick Hughes website.

That’s about it. Unless it’s proven by [add span of years here - usually in excess of 100] years evidnece any warming trend is dismissed, but if there’s one article on a chosen website that say’s it might not be so, well, that’s then ‘true’.

By: Peter Hearnden

Peter Hearnden — Thu, 27 Jul 2006 09:05:17 +0000

#132. Dave, OK, since you talk percentages, one way I see to measure the changes we see in that way is to start from absolute zero, add a degree or two background heat, add ~250C for the effect of the sun, ~33C for ghg's and ~2-3C on top of that for AGW. So, on that basis AGW is, what,

By: Bryn Hughes

Bryn Hughes — Thu, 27 Jul 2006 08:41:09 +0000

“I can’t find the citation but seem to remember that the Artic explorer Nansen deliberately froze his ship in the polar ice in the 1890s but you wouldn’t be able to get a ship that far north today. True or is this my imagination?”
It’s true, it is on the Warwick Hughes website.
As usual this sort evidence is called annecdotal but all Nansens explorations indicate that the Arctic ice pack was less extensive in the 1890s than it has been in recent years.