Solar geoengineering could lead to whiter, brighter skies


June 1, 2012

Solar geoengineering could lead to whiter skies, similar to the hazy and white effect often seen in urban areas (Photo: Shutterstock)

Solar geoengineering could lead to whiter skies, similar to the hazy and white effect often seen in urban areas (Photo: Shutterstock)

We’ve already heard reports that placing small, reflective particles into the upper atmosphere could actually improve crop yields, but would also significantly reduce the amount of electricity generated by solar power plants and do little to arrest the acidification of the world’s oceans. Now another potential side effect has been theorized by Californian researchers, who say that solar geoengineering could lead to whiter skies.

Solar geoengineering is designed to mimic the cooling effect on the planet that results from large volcanic eruptions spewing small particles into the stratosphere that reflect sunlight back into space. While the volcanic particles fall back to Earth after a couple of years, allowing the planet to heat up again, solar geoengineering efforts would constantly replenish a layer of small particles in the stratosphere to help offset the rise in temperatures caused by global warming.

Using advanced models, Ben Kravitz and Ken Caldeira from the Carnegie Institution of Science and Douglas MacMartin from the California Institute of Technology, examined what would happen to the color and brightness of the sky if sulfate-based aerosols were placed into the stratosphere.

What they found was that, depending on the size of the particles, the sky would whiten to a lighter shade of blue during the day, an effect seen in urban areas where the sky often appears hazy and white. Blocking just two percent of the Sun’s light would also result in the sky being three to five times brighter. Additionally, sunsets would have an afterglow.

“These results give people one more thing to consider before deciding whether we really want to go down this road,” Kravitz said. “Although our study did not address the potential psychological impact of these changes to the sky, they are important to consider as well.”

While previous research carried out at Carnegie indicates global crop yields would benefit from solar geoengineering’s potential to cool the planet without affecting CO2 levels, the researchers say changes to the color of the sky would also have an effect on plant life. Because plants grow more efficiently under diffuse light conditions, there is the possibility that global photosynthetic activity would increase, reducing the amount of CO2 in the atmosphere.

Caldeira hopes the team’s work will help discourage any move towards implementing solar engineering.

“I hope that we never get to the point where people feel the need to spray aerosols in the sky to offset rampant global warming,” Caldeira said. “This is one study where I am not eager to have our predictions proven right by a global stratospheric aerosol layer in the real world.”

The researchers' work is published in the journal Geophysical Research Letters.

Source: Carnegie Institution of Science

About the Author
Darren Quick Darren's love of technology started in primary school with a Nintendo Game & Watch Donkey Kong (still functioning) and a Commodore VIC 20 computer (not still functioning). In high school he upgraded to a 286 PC, and he's been following Moore's law ever since. This love of technology continued through a number of university courses and crappy jobs until 2008, when his interests found a home at Gizmag. All articles by Darren Quick

Solar geoengineering is a criminally insane idea. On one hand, these "scientists" are worried about pollution caused by natural atmospheric gases yet they are proposing to sprinkle the atmosphere with a totally foreign substance!

Pure evil and stupidity and a huge dose of hubris!

Guy Macher

I hate to be the one to tell you but, they are already doing this. They will try to tell you that they are only contrails from jet planes but, if you look at normal contrails they don't appear to be anything like the ones from these planes. I have seen clear deep blue skies in the morning and once these planes start spraying out this garbage the whole sky become a muted white blue after they spread out. It is sad that the some scientist think once they gain a small amount of knowledge about how our planet works that they now believe they know everything. Nature does a pretty good job of things on its own without these people interfering.


Please, don't mess with the sky and our atmosphere. It is damaged enough.

Srečko Lavrič

A huge dose of hubris indeed. But is it any larger that refusing to acknowledge human caused climate change and continue to do essentially nothing about it? We are quickly being forced into doing something insane by not doing the sane thing now. Tax carbon now or pay later.


This is insane. Messing with the atmosphere. Scientist are idiotic to try something like this. They have no way of predicting the outcome. Just like when the ecologist tried to save the cork trees. Told the winemakers to use plastic. The demand for cork went down. No demand, the cork tree growers cut down the cork trees for other more profitable crops. Same thing will happen here, there is just know way to predict the outcome of trying something that may well turn slow global warming and natural climate change into a quick extinction level event. If they screw up, how are they going to get the aerosols out of the atmosphere?????

John Weingart

I was surpised to see no mention of chem-trails in this article. This geoengineering is already in action. Surely we have all witnessed the skies criss-crossed with jet trails which persist for hours and spread out all across what was formerly a clear blue sky. Check it out! There are numerous photos and info on the web. It appears that the trails contain Barium and Aluminum particles.

windykites1 utterly depressing and distressing piece....almost beyond imagination...

"...Caldeira hopes the team’s work will help discourage any move towards implementing solar engineering...."

...I could not agree more...too painful to think about...I want to forget this now...


The problem is temperature imbalance Global warming means the surface of the Ocean is heated (stratification). The Earth has plenty of cold water to regulate the atmosphere. Sea water is over 680 times denser than air if you cool off the surface of the Ocean the air would cool off over night. We patented a system to deal with Climate Change.


This is ridiculous. STOP POLLUTING THE ATMOSPHERE! You damn pseudo scientists. All you do is kill the planet. Why do we "need" whiter skies? They should be blue you stupid idiots with the clouds on it, not the whole sky as a single cloud. You go build your own planet and perform stupid experiments. Already enough.

Kirill Belousov

Is that what you call your chemtrails? Solar Geoengineering? Leave the sky alone and it will be fine. Why don't you work on having a whiter, brighter conscience?

Randolph Directo

Really? Have you looked up in the sky lately? Aerosol spraying has already been occurring and has been reported over nearly every major city in the US, Canada and many other countries. These have been referred to as Chemtrails. This Aerosol spraying has been found to be primarily Aluminum based with significant parts of Barium and other pollutants. One simply needs to keep an eye on the sky to see these and do a google search for chemtrails, or what in the world are they spraying movie has an abundance of data available.

Ric Alien

The earth is a self balancing system even if it means wiping out mankind, global warning got nothing to do with saving the earth instead it got everything to do with keeping mankinds status quo.


It's great to have so many people speak up about Chemtrails. I work out doors in LA and have seen easily over 100 days of the criss cross clouds made by planes. This year 2012, there are not as many, so far.

The Hoff

If chemtrails are real why aren't the airlines making huge profits for spaying it?

Global warming proven to be a fraud, no worries we have a new reason to believe CO2 must be controlled and a fascist world government installed.


Enough already! Those who believe in chemtrails better switch to titanium for your tin foil hats which provides extra protection when the zombies come to eat your brain. With the only exception being cloud seeding experiments using silver iodide or dry ice, there are no chemtrails using Aluminum or Barium. As a pilot, we know exactly what goes into, and out of, our planes. What you are seeing is water vapor. That's it, nothing else. Contrails spread out just like a cloud on a windy day. If atmospheric conditions are right, and the vapor trail is back-lit, the contrail appears dark.

Whiter and brighter? Sounds like a Tide commercial.

Bruce Williams

Instead of adding more foreign substances to our polluted skies, why not stop polluting them in the first place?


To Bruce, If what you believe is true and chemtrails are nothing more than misunderstood contrails then why can I go to Florida and never see a contrail in the sky but, in other states such as Georgia, North and South Carolina, Virginia, California and others there are clearly thick white lines that are coming from the back of planes that criss cross to make large x's in the sky that eventually spread out to completely cover the sky and make it a muted white blue? Are you saying that the atmospheric conditions above Florida are never ever ripe for producing these horizon to horizon white plumes that come off the back of high altitude jet planes? I don't claim to know what is in this mess that comes out but, I do know that it is not a contrail as I know what those look like. Please stop using the I'm a pilot line of "I'm a pilot so therefore I know about everything that happens in the sky" routine.


Water vapour forming in jet exhaust depends on air temp and humidity, thats why they form over some locations and not others. why not research human disasters that are actually happening instead of making them up.

Meremere Te Maru

Global Cooling is already offsetting global warming through particulate pollution (opposite effect as greenhouse gasses). This was discover on 9-12-2001 or shortly after when me and coincedentally a scientist noticed it was much brighter outside JUST from grounding all planes. Stopping Particulate pollution could make for accelerated global warming if we can't REVERSE greenhouse gas accumulation. This is an awful idea (basically polluting to offset pollution) but might have to save us one day, i just hope they don't pull the trigger too early.

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