Tom Adams wrote:
> On Jun 20, 9:43 am, William M Connolley <[EMAIL PROTECTED]> wrote:
>> On Wed, 20 Jun 2007, Tom Adams wrote:
>>> In a book about the prehistory of Scotland "Beyond Scotland" it
>>> mentioned that the sea level rose a meter or so (or was it a foot?) in
>>> a few days, causing a good bit of havoc for the humans living along
>>> the coast of the land bridge between Scotland and Europe. Due to an
>>> ice dam failing or a meteor impact hiting Canada's glacier or
>>> something. If we have archeological data about impact of sea level
>>> rise on humans, then, with all the other potential data, I'd think we
>>> might be able to map it out in time pretty well.
>> The meteor idea would suggest that palaeo analogues are even less useful!
>
> I guess you are right that even if we could identify a rapid sea level
> rise event in the paleo record we could no just assume it's due to
> albedo flip.
>
> But I was thinking that we might know more about the rate of the last
> big thaw, the whole thaw, not just that one event that may have been
> caused by a meteor or ice damn break.
Don't forget that when you are looking at the paleo record (especially
termination of the last ice age) you are talking about a time when there
were large ice sheets at relatively modest latitudes, which can soak up
a whole lot of rays. There simply isn't this ice to melt any more.
I've spent some time looking at climate sensitivity and believe that I'm
on solid ground there. I'm reluctant to wade in over Hansen and ice
sheets because I know much less about them, but the argument seems to
follow a similar meme: we "can't rule it out", so we should worry. I'm
also a bit dubious about the language in any case: it's not as if people
are going to be drowned in their beds.
The time I would look for analogues is the last interglacial, when it
was significantly warmer than today. If there is any catastrophic
nonlinearity, one might expect there to have been a rapid sea level rise
at that time. I'm dubious about this having happened, because if there
was a rapid collapse on the 100 year time scale, one might reasonably
also expect a larger long-term change than was seen in practice. But I
don't know how good the data are.
James
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