Atmospheric Brown Clouds

[questioner]

In a recent post, Curious has called attention to ABC's, which are Atmospheric Brown Clouds.

There is a recent report by the UN which deals with this problem.
The report says ABC's produce surface cooling, but warming of the upper atmosphere, resulting in reduced rainfall and snowfall at high elevations.
This is currently having a profound effect on the water supply of India.
Here is a link to the UN report
http://www.unep.org/pdf/ABCSummaryFinal.pdf
A discussion of this man made phenomenon can be found at:
http://tamino.wordpress.com/2008/11/16/abc/#more-1230

The report states changes induced by ABCs with high confidence:

It is certain that ABCs have caused dimming at the surface.

It is certain that soot in ABCs has increased solar heating of the atmosphere.

It is virtually certain that India and China are dimmer (at the surface) today by at least 6 per cent, compared with the pre-industrial values. Absorbed solar radiation at the surface in China and India are lower today by 15 W m-2 or more, compared with the pre-industrial values.

It is highly likely that black carbon (BC) in ABCs has increased the vertically averaged annual mean solar absorption in the troposphere (from the surface up to 14 km in altitude) by about 15 per cent (about 14 W m-2) and the solar heating at elevated levels (1 - 4 km) over India and China by as much as 20 - 50 per cent (6 - 20 W m-2).

Overall, the report concludes that ABCs represent a serious threat to human health and food security, and that the problem is already becoming serious in large regions of Asia. But in a disturbing damned-if-you-do-and-damned-if-you-don’t, eliminating ABCs will also remove the mitigating effect on greehouse-gas warming:


… aerosols in ABCs have masked 20 - 80 per cent of GHG forcing in the past century.

[Co2sceptic]

The following link was sent to us concerning this: -

http://enews.earthlink.net/article/int? ... 3677488935

[Climate Realist]

Are ABCs the next "cause celebre" of the greens?? Will Al Gore quietly drop CO2 when his global warming stance is no longer tenable and start selling ABC credits and "brown cloud busting technologies". Will the term "carbon criminal" be deftly replaced by "ABC" criminal. Will the cute and furry Polar bear be quietly forgotten about and the greens AND AL Gore start preaching to us about the danger oF ABCs threatening those cute and furry Indian tiger cubs?? Dont be brown, be green.

Will ABCs be the cause of catastrophic global cooling as predicted by the IPCC's computer models fed by data collated (corrupted??) by Michael Mann.

The billboard reads "ABCs projected to bring on the next Ice age, and its YOUR fault". (Above a picture of a brown cloud coming out of an SUV blocking the sun and causing the world to ice up).

It would be a joke if it wasn't true.

[Climate Realist]

Questioner- look at the title of this website for a clue. "CO2 Sceptics" not "little brown cloud sceptics".

[Climate Realist]

You can get 6000ft ice sheets on some areas of land (northern hemisphere) by evaporation from the sea and build up of snowfall and expansion of glaciers. This will take thousands of years but then an ice age lasts up to 100,000 years, but a major ice age is currently unlikely as our solar system is currently not in one of the dense arms of the Milky way (see Cosmoclimatology theory). We are in a minor arm of the galaxy, hence Ice at both poles, glaciers on high mountain ranges etc.

We could have a mini Ice-age driven by the quiet sun, such as a Dalton or Maunder minimum event.

My feeling is that ABCs are a last ditch attempt by the greens to blame humans for climate change. Never mind the thin brown clouds, the thick white fluffy low clouds that cover much of the globe are far more efficient at reflecting sunlight.

I have read those articles you refer to.

[ceyda]

I have been reading a little about this and thought this article may be of interest:

http://www.worldclimatereport.com/index ... /#more-257

[ceyda]

Indeed ceyda, but then I have long mentioned the need to regard the 'Material' differences:
'...They discovered that solar absorption, largely by soot, was causing a lot of warming (near 1°C in a day)...'
...of (the solid, being Particulate) Carbon and then (the molecule that is) Atmospheric CO2, and notice also that the article is dated at August 8, 2007.

Yours, Peter K. Anderson aka Hartlod(TM)

Thank you Hartlod,

It is a case of that better pollution control would be a better way of helping to reduce temperature.

See also:

http://www-ramanathan.ucsd.edu/VRpdfFil ... _final.pdf

[questioner]

Ceyda,
The link in my opening post pointed out that there are local increases in temperature in Asia associated with these brown clouds due to carbon, but that globally the sulfate particles produced have a net cooling effect and on balance are suppressing global warming by 20 to 80% of what it would be without the ABC's.
Some posters are focussing their attention on the local black carbon heating effect only, rather than the global sulfate cooling effects which are artificially cooling the earth as a whole.
The Ramanathan paper in its conclusion says,
"The negative forcing (cooling effect) from aeorosols can be compared to the positive forcing from GHG emissions. .."