Posted on 04/19/2009 5:37:54 PM PDT by neverdem
Contact: Mary Beckman
mary.beckman@pnl.gov
509-375-3688
DOE/Pacific Northwest National Laboratory
RICHLAND, Wash. -- By sampling clouds -- and making their own -- researchers have shown for the first time a direct relation between lead in the sky and the formation of ice crystals that foster clouds. The results suggest that lead generated by human activities causes clouds to form at warmer temperatures and with less water. This could alter the pattern of both rain and snow in a warmer world.
The lead-laden clouds come with a silver lining, however. Under some conditions, these clouds let more of the earth's heat waft back into space, cooling the world slightly. Atmospheric lead primarily comes from human sources such as coal.
The international team of researchers reported their results in the May issue of Nature Geoscience. The collaboration included researchers from institutions in the United States, Switzerland and Germany.
"We know that the vast majority of lead in the atmosphere comes from man-made sources," said atmospheric chemist Dan Cziczo of the Department of Energy's Pacific Northwest National Laboratory and study author. "And now we show that the lead is changing the properties of clouds and therefore the balance of the sun's energy that affects our atmosphere."
Globe Trotting for Lead
Scientists first attempted to goad rain from the sky with silver and lead iodide in the 1940s. Since then, researchers have known that lead can pump up the ice crystals in clouds. But daily human activities also add lead to the atmosphere. The top sources include coal burning, small airplanes flying at the altitude where clouds form, and construction or wind freeing lead from the ground. Cziczo and colleagues wanted to know how lead from these sources affects clouds.
To find out, the researchers collected air from high atop a mountain peak on the Colorado-Wyoming border. In their high altitude lab, they created artificial clouds from the air in a cloud chamber about the size of a small refrigerator. Half of the ice crystals they plucked from the synthetic clouds, they found, contained lead.
The team then collected a dollop of real cloud atop a mountain in Switzerland. About half of those ice crystals also contained lead. But finding lead in an incriminating position doesn't mean it causes ice crystals.
To determine whether lead causes ice crystals and clouds to form, the team turned to a lab in Germany that houses a cloud chamber three stories tall, as well as a smaller chamber in Switzerland. They created dust particles that were either lead-free or contained one percent lead by weight, which is about what scientists find in the atmosphere. They put these dust particles into the chambers and measured the temperature and humidity at which point ice nucleated around the dust.
They found that lead changed the conditions under which clouds appeared. The air didn't have to be as cold or as heavy with water vapor if lead was present.
"Most of what nucleates clouds are dust particles," said Cziczo. "Half of the ones we looked at had lead supercharging them."
Leaden Clouds, Cooler Climes
To investigate what this might mean for the earth's climate, the researchers simulated the global climate with either lead-free dust particles floating around, or with either 10 percent or all of them containing lead.
The computer simulation showed that the clouds they looked at -- typically high, thin clouds -- formed at lower altitudes and different locations in the northern hemisphere when lead was present in dust particles. This will probably affect precipitation, said Cziczo.
"In our atmosphere, lead affects the distribution and density of the kinds of clouds we looked at," said Cziczo, "which might then affect where and when rain and snow fall."
Clouds at lower altitudes let more of the earth's heat, or so-called longwave radiation, escape out to space. So lead-triggered clouds could partly offset global warming due to greenhouse gases.
But that doesn't mean lead in the atmosphere will simply cool the planet, said Cziczo, since they looked at only one type of cloud. Cloudy skies are far more complicated than their wispy image lets on.
"This work highlights how complex these interactions between lead and water vapor and temperature are," said Cziczo. "They're not as simple as greenhouse gases."
Future work will look at the type of lead and how much is needed to affect clouds and precipitation, as well as the atmospheric distribution of the metal dust.
Reference: D. J. Cziczo, O. Stetzer, A. Worringen, M. Ebert, S. Weinbruch, M. Kamphus, S. J. Gallavardin, J. Curtius, S. Borrmann, K. D. Froyd, S. Mertes, O. Möhler and U. Lohmann, Inadvertent Climate Modification Due to Anthropogenic Lead, Nature Geoscience, May 2009, DOI 10.1038/NGEO499 (http://www.nature.com/ngeo/index.html).
This research was supported by the Atmospheric Composition Change the European Network for Excellence, ETH Zurich, the German Research Foundation, and Pacific Northwest National Laboratory directed research funding.
Pacific Northwest National Laboratory is a Department of Energy Office of Science national laboratory where interdisciplinary teams advance science and technology and deliver solutions to America's most intractable problems in energy, national security and the environment. PNNL employs 4,250 staff, has a $918 million annual budget, and has been managed by Ohio-based Battelle since the lab's inception in 1965. Follow PNNL on Facebook, LinkedIn and Twitter.
I saw on Myth busters where they made and flew a lead baloon so I guess atmospheric lead is possible......
I doubt it
Hmmmm....soooo...there must be a LOT of lead around tropical forests at times....and especially in the Olympic Rainforest in WA State....
> “We know that the vast majority of lead in the atmosphere comes from man-made sources,” said atmospheric chemist Dan Cziczo of the Department of Energy’s Pacific Northwest National Laboratory and study author.
Yes, I get it. It’s our fault. If only those cavemen knew that driving their SUV’s were going to kill us in the 21st century.
......If only those cavemen ......
Back then there were no clouds. Rain came from out of the blue. Not until the development of tetraethyl lead and lead paint did it become airborne.
Lead is also projected into the atmosphere by smelters and by coal fired power plants. This is a good reason for getting rid of coal fired power plants and replacing them with nuclear power plants.
This is the point where someone shows a picture of all the solder joints in the walls of the cloud chamber and a little kid says, “hey, exactly how was that chamber constructed?” Then hilarity ensues.
This is another scare scam foisted on us by those who hate the industrial revolution and what it has meant in the ADVANCEMENT of most of our lives. They, the folks who brought us the global warming hoax, are guilty of drinking their bathwater. By the way, there is lead in that bathwater.
At least they use the term “inadvertent”, does that modify the word “laden”?
I have flown through many clouds in me almost 20,000 hours of flight time. If I had any suspicion that there was lead in those clouds I’d have stayed on the ground!
silver solder.....
The lead from gasoline (except for aviation gas) is expelled at ground level and stays close to the ground. On the other hand, smelters and power plants tend to have very tall smokestacks and expel the lead into the atmosphere.
This is a “Thank you China” moment. Their pollution has reached world beating status.
We did, of a different kind. As I recall, some research showed that children in the poorer urban areas near lots of highways and traffic took a hit in mental and learning capabilities.
Unfortunately, those kids grew up and began voting before the benefits of less lead were fully felt. Hence, Al Franken, Obama and other assorted undesirables actually reaped the rewards of lead in the gasoline.
Come to think of it, pollution would be a very good play for the China card - they couldn’t clean up their country without a revolution.
The West should charge two or three trillion for the massive job required.
ALL that lead in the air is my fault... from all the ducks and geese I’ve shot at over the years...
Environmentalists are destroying the world!
I still have my old lead jock strap from when my research took me to use the cyclotron at Lawrence...I could sell it to Al Gore.
Come here to Appalachia for a visit and meet some of my coal-miner buds.
Nuke is good, though.
According to Science Daily, Sept,1998, lead has been released into the atmosphere since the first plow broke the soil.
“The researchers found that the release of lead to the atmosphere, probably from soil erosion produced when early peoples cleared land for agriculture, began to increase over natural levels about 6,000 years ago.”
Virtually any activity releases lead it seems.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.