Global Dimming - The climatalogical X-factor?

[Ophiolite]

This is quite simply the most remarkable item I have read in two decades or more. I am astounded. I checked the date on the article three times to make certain it wasn't an April Fool joke. I can't believe I have never run across this before.

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

 

Some quotes in summary:

 

 

Each year less light reaches the surface of the Earth. No one is sure what's causing 'global dimming' - or what it means for the future. In fact most scientists have never heard of it.

Atsumu Ohmura at the Swiss Federal Institute of determined that levels of solar radiation striking the Earth's surface had declined by more than 10% in three decades.

 

The finding went against all scientific thinking. When Ohmura eventually published his discovery in 1989 "It was ignored" .

 

Records show that over the past 50 years the average amount of sunlight reaching the ground has gone down by almost 3% a decade. It's too small an effect to see with the naked eye, but it has implications for everything from climate change to solar power and even the future sustainability of plant photosynthesis

 

"It's an extraordinary thing that for some reason this hasn't penetrated even into the thinking of the people looking at global climate change," says Graham Farquhar, a climate scientist at the Australian National University in Canberra. "It's actually quite a big deal and I think you'll see a lot more people referring to it."

 

Several other research papers published during the 1990s reported that sunshine in Ireland was on the wane, that both the Arctic and the Antarctic were getting darker and that light in Japan, was falling. Levels of solar radiation reaching parts of the former Soviet Union had gone down almost 20% between 1960 and 1987.

 

 

The problem is that most of the climate scientists who saw the reports simply didn't believe them. That began to change in 2001, when Stanhill and his colleague Shabtai Cohen at the Volcani Centre in Bet Dagan, Israel collected all the available evidence together and proved that, on average, records showed that the amount of solar radiation reaching the Earth's surface had gone down by between 0.23 and 0.32% each year from 1958 to 1992.

And so it continues. Quite remarkable

[ed84c]

its not it was on horizon the other day

[Ophiolite]

It's not what?

[Sayonara]

An April Fool's joke, presumably.

[ecoli]

Maybe they only took measurements on cloudy days?

[coquina]

I have been out on the Chesapeake on a hot humid day and seen the brown smog hanging over the cities of Hampton and Norfolk, and extending high into the atmosphere. When you are in it, you don't notice the difference, but when you are out in the clear and looking into it, it is easy to see that the amount of light reaching the ground is impeded by it. As the air currents disperse the smog globally, it's less noticable, but surely a good part of very small particulate matter remains suspended in the air.