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-   -   Reflecting particles as a solution to global warming? (http://www.physicsforums.com/showthread.php?t=178375)

EnumaElish Jul26-07 03:33 PM

Reflecting particles as a solution to global warming?
 
This was on PBS's NOVA a few months back.

A by-product of greenhouse gas emissions is what I am going to term "macro particles." Thanks to their size and composition, these particles have been reflecting sunlight and therefore reducing global warming, although on balance they could not reverse it.

In the absence of these particles, the greenhouse effect would have been more severe. A scientist on NOVA claimed that these particles have reduced the warming effect by about 20%.

Are there studies of how this information can be used to further reduce or even reverse GW?

Mk Jul26-07 03:51 PM

Reverse global warming?

What global warming?
http://www.giss.nasa.gov/edu/gwdebate/00fig1.gif
Reverse how many degrees?

EnumaElish Jul26-07 05:43 PM

Mk

The image link returns a "+".

Did you mean to seriously respond to my post? Or are you just bored?

billiards Jul26-07 07:48 PM

The figure comes up for me, it's part of this article:

http://www.giss.nasa.gov/edu/gwdebate/

I fail to see Mk's point, what global warming? How about the positive upward trend clearly seen as a red line on the graph?

EnumaElish, I believe this story is quite old news, these particles increase the albedo of clouds, less sunlight reaches the surface (a phenomenon that has been termed "global dimming"). Some say that the effect of these particles has masked the increased strength of the atmospheric greenhouse effect, and that as a result recent temperatures have been cooler than they might otherwise have been. However, new technologies have been developed which have dramatically decreased the need to release these particles, as a result their concentration in the atmosphere will diminish. Potentially this will enable the effect of the greenhouse gases to be more dominant in global warming... although one must bear in mind, there are many more layers of complexity which we are yet to unfold, we are in no position to tamper with earth's climate in a manipulative, intelligent way, the results of releasing more "cooling" particles could be disastrous for unseen reasons.

mgb_phys Jul26-07 08:00 PM

It's 150 year old news!
The eruption of Krakatoa put enough sunlight reflecting material into the atmosphere to basically prevent summer happening for most of the world, leading to widespread frost, famine etc.
Recently there was a measurable rise in temperatures across the US for a couple of days after 9/11 when flights were grounded and so not generating highly reflecting contrails.

Mk Jul27-07 04:09 AM

Actually I see a tiny plus as well now. I'm sorry about that. I meant that in a our chaotic system, what is about two degrees?

Ivan Seeking Jul27-07 04:20 AM

Here's a scary one

Quote:

A method is disclosed for reducing atmospheric warming due to the greenhouse effect resulting from a greenhouse gases layer. The method comprises the step of seeding the greenhouse gas layer with a quantity of tiny particles of materials characterized by wavelength-dependent emissivity or reflectivity, in that said materials have high emissivities in the visible and far infrared wavelength regions and low emissivity in the near infrared wavelength region. Such materials can include the class of materials known as Welsbach materials. The oxides of metal, e.g., aluminum oxide, are also suitable for the purpose. The greenhouse gases layer typically extends between about seven and thirteen kilometers above the earth's surface. The seeding of the stratosphere occurs within this layer. The particles suspended in the stratosphere as a result of the seeding provide a mechanism for converting the blackbody radiation emitted by the earth at near infrared wavelengths into radiation in the visible and far infrared wavelength so that this heat energy may be reradiated out into space, thereby reducing the global warming due to the greenhouse effect.
The details are clearly outlined in U.S.
Patent #5,003,186 at the following link.
http://patft.uspto.gov/netacgi/nph-P...S=PN/5,003,186

No way would I support such drastic actions unless we had extremely high confidence that it was necessary.

billiards Jul27-07 05:42 AM

Plan to dump iron in the ocean to offset atmospheric carbon dioxide.

http://news.nationalgeographic.com/n...ron-ocean.html

Renge Ishyo Jul27-07 08:04 PM

I wish the politicians would go back to the whole "we need to save the trees" spiel from the 80's and lose the "we need to stop global warming" spiel of the present. I mean it was a much less frightening thought to have someone put some unshaved woman up in a tree than it is to have someone actually considering intentionally polluting the atmosphere with potentially harmful chemicals in the hopes of lowering the temperature by a fraction of a degree.

Ivan Seeking Jul28-07 03:19 AM

Quote:

Quote by Renge Ishyo (Post 1388373)
I wish the politicians would go back to the whole "we need to save the trees" spiel from the 80's and lose the "we need to stop global warming" spiel of the present. I mean it was a much less frightening thought to have someone put some unshaved woman up in a tree than it is to have someone actually considering intentionally polluting the atmosphere with potentially harmful chemicals in the hopes of lowering the temperature by a fraction of a degree.

That is a very naive interpretation of the environmental movement. The GW issue is driven by science. Of course the guys down at the local bar would probably disagree; in between belches. :biggrin:

mgb_phys Jul28-07 02:53 PM

But it's quite a good interpretation of most goverment's conception.
We screwed up the atmosphere by large scale industrial processes where we didn't understand/care about the long term effects, therefore the solution must be a large scale industrial process where ....... etc

Renge Ishyo Jul29-07 08:33 PM

That is a very naive interpretation of the environmental movement. The GW issue is driven by science.
-------------------------------------------------------------------------------------

Similiar science driven arguments were given in the 80's for all the save the whales, trees, etc. movements. For example, people back then were focusing on rates of deforestation, or darwinian genetics, etc. as scientific basis for the save the "insert species here" movements citing similiar day of doom scenarios as those for the global warming movement of the present.

The real reason behind all these movements may very well be to give government an excuse to exert controls on industry (the science merely the vehicle used to justify that end), but I suppose I just liked it more when these psuedo science political movements actually had small positive solutions that people were doing (like actually planting trees and saving pointlessly rare animals in rainforests or whatnot). What positive results are coming out of the global warming movement? People buying more Toyota's?

mgb_phys Jul30-07 12:16 AM

Quote:

Quote by Renge Ishyo (Post 1389681)
What positive results are coming out of the global warming movement?

In europe energy saving CFD light bulbs are becoming the standard, people are seeing recycling as a duty and I think fashions have turned against SUVs.
Of course this is more than offset by the increased amount of flying people do !

Renge Ishyo Jul30-07 07:11 PM

And don't get me wrong, the technology that the hybrids use (harvesting the extra heat generated during combustion to charge a battery) is an excellent idea to be sure and an improvement environmentally. Though I am not sure the global warmers can take credit for the recycling movement, that was an 80's success all the way.

I am actually quite enthusiastic about the idea of politicians breathing less often as a solution to global warming...this would certainly lead to decreased overall CO2 levels. The challenge with getting this through I suppose would be to convince a politician that they actually breathe out CO2 to begin with (it's already hard enough to convince them that they are contradicting themselves when they buy 10 SUV's).

EnumaElish Aug6-07 12:02 PM

I am guessing that the degree of inclination to agree with GW issues is positively correlated with one's gradient to the nearest open body of water.

Renge Ishyo Aug6-07 06:30 PM

Not necessarily. I live near a body of water and I am sort of in the middle on the global warming issue. I am much more for the older save the trees type movements because at least I could see that the "direct" goal that people were told to work for in those was to protect life.

I've listened to the arguments for GW, and while I agree that it is happening, the arguments that I have heard about the "real" dangers of global warming are poor at best. For example, I am told that in 100 years some beachfront property will be lost due to the rising sea level. Trouble is, as anybody living near these things knows, long before that can even happen people in beachfront properties will have to rebuild their properties several times over in that same time period. Why? One reason is that the rate of coastal erosion due to the attack from ocean waves on the beachfront is a MUCH faster and more dynamic process than sea level rise (you can see dramatic changes to most beachfronts just looking at pictures that are ten years apart). Living on the beach to begin with is impractical (expensive) at present mainly for this reason and NOT GW. That's why only rich people who afford the hefty insurance do it (well, and bums who live without a real home on the beach...but there is no danger to their "property").


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