Global Dimming: The Hidden Threat to Our Planet's Climate

[coberst]

Good-by Sunshine

Recently I watched the documentary “Dimming Sun” that was played by Nova on PBS TV.

This show described the nature of a problem in which the sunlight reaching the earth’s surface is being diminished by air pollution.

A researcher from Swiss Federal Institute of Technology in 1985 discovered strong evidence that the sunlight reaching the earth’s surface had diminished by more than 10% of that recorded in the 1960s.

Most scientists ignored this evidence and it is only recently that science has become focused on this problem and has developed further evidence of this phenomenon called ‘global dimming’.

A particular alarming aspect of this phenomenon is that global dimming acts opposite to global warming and there is the conclusion that because of this opposition that the greenhouse effect causing warming is far more rapid than concluded because the effects of air pollution, which would cause global cooling, have balanced out a great part of the warming effects.

Two forces operating in opposition have masked the rapidity of the effects of the greenhouse effect.

http://www.guardian.co.uk/life/feature/story/0,13026,1108853,00.html

http://www.pbs.org/wgbh/nova/sun/about.html

“The good news is that pollution controls have slowed and possibly even halted global dimming during the last decade. The bad news—and the ironic twist in Nova's story—is that without pollution, more sunlight is reaching Earth, revealing the full impact of global warming. Although all climate models have important uncertainties, the unsettling implication is that, with dimming fading away in many regions, global temperatures may rise even faster than most models have predicted.”

 

[Integral]

I noticed that the Guardian article is 5yrs old and that the Nova is 2yrs old. Is there any up to date info on this?


I am moving this thread out of Philosophy ? to Earth Sciences.

 

[Andre]

You might like to read the real climate take on, from Gavin Schmidt on their page 105, 18 January 2005. If climate alarmist Gavin says it's all exagarations, what can we add to that?

Anyway see also the IPCC 4AR report:

http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter7.pdf

A lot of words in there but nothing specifically identifying global dimming as a big factor.

 

[coberst]

I noticed that the Guardian article is 5yrs old and that the Nova is 2yrs old. Is there any up to date info on this?


I am moving this thread out of Philosophy ? to Earth Sciences.

http://www.nasa.gov/centers/goddard/news/topstory/2007/aerosol_dimming.html

 

[Evo]

Very interesting, thanks coberst. But the thread title should be "Hello Sunshine" since the reduction in pollution has increased the amount of sun and warmth from the sun on the earth.

Global 'Sunscreen' Has Likely Thinned, Report NASA Scientists03.15.07

A new NASA study has found that an important counter-balance to the warming of our planet by greenhouse gases – sunlight blocked by dust, pollution and other aerosol particles – appears to have lost ground.

The thinning of Earth’s “sunscreen” of aerosols since the early 1990s could have given an extra push to the rise in global surface temperatures. The finding, published in the March 16 issue of Science, may lead to an improved understanding of recent climate change. In a related study published last week.

Ironic that reducing pollution is increasing Global Warming.

 

[coberst]

Very interesting, thanks coberst. But the thread title should be "Hello Sunshine" since the reduction in pollution has increased the amount of sun and warmth from the sun on the earth.



Ironic that reducing pollution is increasing Global Warming.

Therein lay the rub. It is perhaps the case that any cleaning of our air may mean a quick increase in global warming rates.

 

[Andre]

Therein lay the rub. It is perhaps the case that any cleaning of our air may mean a quick increase in global warming rates.

It doesn't seem to work that way. In Western Europe the skies are much cleaner again yet we still have had a moderate bad summer. But that's merely ad hoc talk. Also the global temperatures seem to level off for several years now.

The real point is that the atmosphere is a very efficient air conditioner, if for some reasons the heating of the surface increases, warming up the lower atmosphere then convection currents remove much of that excess heat to the higher atmosphere, where it radiates out more effectivily.

See also this thread.
https://www.physicsforums.com/showthread.php?t=252066

 

[Furlock]

This may be of your interest. I have studied through the last seven years the conditions of light (sunlight) at a daily base. The study refers to the light conditions in a small part of Spain, located in the south.

Overall, and just as a remark, there has been a sort of light (and colour) dimming, clearly constatable and measureable during at least 2001 (beginning of the study) until midst of 2007. There is from this moment on until 2008 (september) a clearly identificable general "improvement" of light (too many factors and variables as to define it in a forum message), and octuber and november are showing incredible values, an improvement far beyond what I encountered back in 2001.

It is possible that the actual conditions of light (clearness of atmosphere, structured layers of different temperatures, others) are even better than before 1900. At least under the about 400 elders I could have asked in the last two months, no one remembers having seen such clearness of skies and colours.

My study, unfortunately does not lead towards an answer to the dimming question, but you may encounter interesting that this effect has been recorded clearly, and now has changed or converted into an even more complex situation to explain.

It is very difficult to understand why at this point of massive pollution the region has not only recovered, but you may think you are breathing air that pure as some thousand years ago. From a metereological point of view or analysis there is no possible explanation available. At least from my point of view, it is impossible that a certain region of the world recovers totally, while others are deeply buried under contaminated skies.

Kindos regardos,


Miguel



http://furlock.zenfolio.com/img/v4/p884955126-5.jpg
November

Others:
http://furlock.zenfolio.com/img/v1/p115671499.jpg
2007 - first days of nearly abrupt changes

http://furlock.zenfolio.com/img/v4/p34690944-5.jpg
November
http://furlock.com/foro/index.php?action=dlattach;topic=16.0;attach=11;image
November


(My study is not about the topic and the here shown photographs are not data to be used on behalf of the topic, but underline quite easily the expressed. )