[LINK] IPA, astroturfing and fantsy themes

[jim birch]

TKoltai <tomk at unwired.com.au> wrote:

> Regarding the scientific concerns; I would like to comment that
> climatologists are ignoring the perturbatious orbit that the earth
> actually travels in


Ignoring what?  Orbital variations are taught in in undergrad climatology
classes.  They've been studied and modelled by climatologists for a long
time.

There is a significant correlation of ice ages with orbital perturbations
but it's not the whole story.  Some peaks and troughs of orbitally inferred
insolation are missing from the climate record and the time lags aren't
consistent.  There are also real variations in output of the sun at shorter
time scales as well as the much more slowly varying orbital perturbation
effect.  Currently, net solar insolation is expected to decrease over the
next century but the impact will be at least an order of magnitude less
that the greenhouse gas impact at current projected emissions.  These
predictions don't ignore orbital effects - they're just relatively small on
the timescale of the next century or two.

All this stuff is well known.  There is plenty of ongoing research into the
climate's sensitivity to various inputs including net insolation, CO2,
particulate pollution, volcanoes, etc, but orbital perturbations haven't
fallen off the list by some clerical error.  They're just not that
important.  In the denialists' parallel universe there are a succession of
"discoveries" that are an established part of the climatological literature
over here in this universe.

See for example, the "It's the sun!" section in the myth list at
http://www.skepticalscience.com/argument.php

Anyone who still has doubts about AGW and knows what linear regression is
should look at this too.  Removing variations in total insolation, El Nino,
and volcanic particulates from the temperature record for the last 30 years
gives an unequivocal and surprisingly steady warming signal:
http://tamino.wordpress.com/2011/12/06/the-real-global-warming-signal/

Jim





Jim