Text 11870, 52 rader
Skriven 2007-02-09 01:45:24 av Shabaz (15311.babylon5)
  Kommentar till text 11869 av rec.arts.sf.tv.babylon5.moderated (15310.babylon5)
Ärende: Re: Global warming, among other things
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On Feb 9, 9:55 am, "Shabaz" <shaba...@gmail.com> wrote:
> On Feb 9, 8:09 am, "Soundy" <soundy...@gmail.com> wrote:
>
> > On Feb 8, 10:42 am, "Shabaz" <shaba...@gmail.com> wrote:

> The scenarios are not the same thing as the models. The SRES scenarios
> project what is deemed a plausible development of the future, and
> don't really concern climatic effects at all.

Ok, upon reading that again, I didn't make the difference between
models and scenarios quite as clear as it could've. So let me copy
paste the description of one of the SRES scenarios as summarized by
the AR4 SPM to illustrate exactly what a scenario is:

>>The B1 storyline and scenario family describes a convergent world with the
same global population, that peaks in mid-century and declines thereafter, as
in the A1 storyline, but with rapid change in economic structures toward a
service and information economy, with reductions in material intensity and the
introduction of clean and resource efficient technologies. The emphasis is on
global solutions to economic, social and environmental sustainability,
including improved equity, but without additional clim
ate initiatives.<<

So these are projected developments in global socio-economic
developments, and technology, and societal developments; things like
that. And they produce several of these scenarios, to give a good
spread of what is likely to happen in these areas. Each of these
scenarios is then plugged into multiple models to see what happens
with global mean temperature rise and global sea level rise and
several other things. The range of model results for each scenario is
then averaged to give a best estimate and likely range for what would
happen climatologically if each of these scenarios would come to pass.

> Average volcanic activity is accounted for in models and has been for
> decades, far as I know.

I looked up the study I was thinking of here btw, which was Hansen et
al. 1988 (http://tinyurl.com/rvyfz) based on 3 projections he had
given to the US Congress earlier that year. Two of which took into
account a large volcanic eruption in 1995. Which ended up being off by
4 years, with Mount Pinatubo erupting in 1991, but did correctly
incorporate a large volcanic eruption for the timeframe it was
projecting, because it was deemed likely to happen within that
timeframe. Which proves that if it is at all likely based on the then
current science that something is to happen in a certain timeframe,
then it is usually accounted for, even 2 decades ago. And our
understanding has gone way, way up compared to then in those 2
decades.

-Shabaz
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