Horizon - Global Dimming/Warming

Allan Mud wrote:

>Which is what I understood the program to have expalined, it was the
soot
>and general pollution in the atmosphere actually cooling things down
by
>absorbing/reflecting sunlight by creating clouds that are more dense
than
>those naturally created and the greenhouse gases that were adding to
global
>warming.

>Now that we're on an enviromental crusade to reduce all the soot and
>pollutants in the atmosphere we're accelerating global warming as we
haven't
>done enough to also reduce emmissions of greenhouse gasses.

The program should have been right, if they should have given details
about what the different aerosols do. Sulphate aerosols are of
particular interest, as they attract water and may seed clouds. These
reflect more sunlight back to space. Other aerosols (natural or
human-induced) like sea-salt, Sahara sand, fertiliser,... reflect
sunlight, but don't attract water. Soot aerosols absorb sunlight and
thus heat the surrounding air. The net effect is that sulphate aersols
have the highest direct and indirect (on clouds) cooling impact,
followed by the others for mainly direct impact, while soot aerosols
have a net warming effect. See the graphs 1d-1h of the IPCC for the
different results of human-induced aerosols at:
http://www.grida.no/climate/ipcc_tar/wg1/fig6-7.htm

Thus reducing pollution, especially soot, will be beneficial for
health anyway, without causing a runaway warming effect, instead it
will give some cooling.

Ferdinand

In message <[email protected]>
[email protected] (FerdiEgb) wrote:

> Allan Mud wrote:
>
> >Which is what I understood the program to have expalined, it was the
> soot
> >and general pollution in the atmosphere actually cooling things down
> by
> >absorbing/reflecting sunlight by creating clouds that are more dense
> than
> >those naturally created and the greenhouse gases that were adding to
> global
> >warming.
>
> >Now that we're on an enviromental crusade to reduce all the soot and
> >pollutants in the atmosphere we're accelerating global warming as we
> haven't
> >done enough to also reduce emmissions of greenhouse gasses.
>
> The program should have been right, if they should have given details
> about what the different aerosols do. Sulphate aerosols are of
> particular interest, as they attract water and may seed clouds. These
> reflect more sunlight back to space. Other aerosols (natural or
> human-induced) like sea-salt, Sahara sand, fertiliser,... reflect
> sunlight, but don't attract water. Soot aerosols absorb sunlight and
> thus heat the surrounding air. The net effect is that sulphate aersols
> have the highest direct and indirect (on clouds) cooling impact,
> followed by the others for mainly direct impact, while soot aerosols
> have a net warming effect. See the graphs 1d-1h of the IPCC for the
> different results of human-induced aerosols at:
> http://www.grida.no/climate/ipcc_tar/wg1/fig6-7.htm
>
> Thus reducing pollution, especially soot, will be beneficial for
> health anyway, without causing a runaway warming effect, instead it
> will give some cooling.
>
> Ferdinand

While our pollution certainly doesn't help, it is worth noting
that in Roman times grapes were grown in Southern Scotland
and in Dickens' time the Thames regularly froze over.
While dealing with polution is a must, it is also important
to factor in the (seemingly) regular climate changes before
coming to a conclusion - not a trait of TV programmes
that try to imply they are giving all the facts.

Just my 2p's worth.

Richard
--
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Running a business in a Microsoft free environment - it can be done
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beamendsltd wrote:

> While our pollution certainly doesn't help, it is worth noting
> that in Roman times grapes were grown in Southern Scotland
> and in Dickens' time the Thames regularly froze over.
> While dealing with polution is a must, it is also important
> to factor in the (seemingly) regular climate changes before
> coming to a conclusion - not a trait of TV programmes
> that try to imply they are giving all the facts.

....and wheat was grown in Greenland too.

Steve

"Steve Taylor" <[email protected]> wrote in message
news:[email protected]...
> beamendsltd wrote:
>
> > While our pollution certainly doesn't help, it is worth noting
> > that in Roman times grapes were grown in Southern Scotland
> > and in Dickens' time the Thames regularly froze over.
> > While dealing with polution is a must, it is also important
> > to factor in the (seemingly) regular climate changes before
> > coming to a conclusion - not a trait of TV programmes
> > that try to imply they are giving all the facts.
>
> ...and wheat was grown in Greenland too.
>

But those facts water down the argument so they have to be left out. Same
with the vapour trails thing - requires specific atmospheric conditions for
them to form at all, and even more specific conditions for them to form,
persist and spread. Most often the specific conditions for formation occur
above existing cloud anyway so it makes absolutley no difference. No denial
that they do affect the temp range when they form and spread on an otherwise
clear blue day, but the conditions are local (certainly not USA wide, as the
programme suggested) and certainly no worse than a whiff of cirrus or the
build-up of cumulus on an otherwise clear and beat day.

If you've got an axe to grind, it's dead easy to find some facts and
statistics that you can quote to support the swing of that axe, especially
if you quote them in isolation from any non-supportive arguments, facts and
statistics. I noticed how the "scientist" had his focus on one specific
little patch of California with four or five trails across it. Probably got
a PhD out of it too. They'll be banning fox hunting next and pretending
that badgers don't spread TB into cattle!!

Steve

So Steve was, like

> They'll be
> banning fox hunting next and pretending that badgers don't spread TB
> into cattle!!
>
> Steve

Nah, could never happen here....

--

Rich

Pas d'elle yeux Rhone que nous