On Feb 7, 10:47 am, "Michael Tobis" <[EMAIL PROTECTED]> wrote:
> On 2/6/07, Gareth <[EMAIL PROTECTED]> wrote:
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> > Take a look at Figure SPM-5 in the SPM - AOGCM projections of surface
> > temperatures. For the period 2020-29 there is very little difference
> > in projected temperature rise (from 1980-99) between the three
> > scenarios illustrated (B1, A1B, A2). The SPM says "Best-estimate
> > projections from models indicate that decadal-average warming over
> > each inhabited continent by 2030 is insensitive to the choice among
> > SRES scenarios, and is very likely to be at least twice as large as
> > the corresponding model-estimated natural variability during the 20th
> > century." My eyeball suggests that the rise is about 0.8C.
>
> > I'd like to explore some of the implications of this finding. It
> > suggests, for instance, that we have in effect got a "forecast" of
> > global average temperature change over the next 25 years. We're
> > committed to this warming whatever we do.
>
> Yup.
>
> I think Roger Pielke argues that since this is the case there is no hurry
> in determining a policy. I think "discount rate" economics formalizes that
> argument.
> The problem with this is that it will always be true. Any action
> we take will have modest and essentially undetectable output for a couple of
> decades at least, and the early decades dominate the economic calculus. It
> seems to me that going from there to a conclusion that we should never have
> a policy is not sensible.
>
> From a policy perspective,
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> > we therefore have a known challenge to meet (even if we don't/can't
> > know the full implications of that 0.8C). Adaptation is required, and
> > to enable us to plan effective adaptation, we will have to work on
> > refining projections (both regionally and globally) of near-term
> > (10-20 year) change. I know that some work is being done on using
> > AOGCMs as seasonal forecast tools at the Hadley Centre - but is this
> > seen as an important research focus? It strikes me that this is one
> > area with huge policy relevance.
>
> Seasonal forecasting is pretty different from policy time scales. I may be
> wrong, but my impression is that GCMs in a dynamic prediction mode (as
> opposed to a statistiucal prediction mode) are unlikely to get much
> information out beyond a year or two, and such as there would be would only
> capture some of the variance associated with the upper ocean.
>
> Do you have a reference? My impression is that this work is more akin to
> weather prediction than climate prediction. The models are similar but the
> sorts of information we expect to get out of them are very different.
>
> Of course, this doesn't mean that we can afford to ignore mitigation.
>
> > The spread of the red curves (2090-99) in SPM-5 gives a good
> > indication of what early action on GHGs might achieve. Policies
> > designed to minimise warming by the end of the century are clearly
> > essential, but they're not the only game in town. Does the WG2 draft
> > reflect this? While the international political community focusses on
> > Kyoto-2, are we failing to prepare for the inevitable?
>
> What specific policy actions do you think might be indicated regarding
> adaptation on the decadal time scale?
>
> I think this is an interesting question so in the interest of keeping it
> going I will venture a bit of more or less uninformed opinion.
>
> I have heard that the Nature Conservancy is pulling back from investments in
> littoral ecosystems on the grounds that they are going away anyway. Like
> butterflies and pine trees, I think you will find ski resort interests
> putting more effort poleward and less at the equatorward end of their range.
>
> The policy question is what sorts of adaptation directly affect public
> infrastructure.
>
> Off the top of my head I think this will have more to do with water (and in
> some locations with wind) than with temperature. Should countries like the
> US and China which span a wide range of climates move their investments
> poleward and inland? Or should they buck the trend and shore up the
> shoreline and find water for the subtropics?
>
> mt- Hide quoted text -
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> - Show quoted text -
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