Here is an extract from the article. The "Geritol Solution" intrigues me. The others don't look feasible.
The Geritol solution
A private company is already carrying out this plan. Some scientists call it promising while others worry about the ecological fallout.
Planktos of Foster City, Calif., last week launched its ship, the Weatherbird II, on a trip to the Pacific Ocean to dump 50 tons of iron dust. The iron should grow plankton, part of an algae bloom that will drink up carbon dioxide from the atmosphere.
The idea of seeding the ocean with iron to beef up a natural plankton and algae system has been tried on a small scale several times since 1990. It has both succeeded and failed.
Planktos chief executive officer Russ George said his ship will try it on a larger scale, dumping a slurry of water and red iron dust from a hose into the sea.
"It makes a 25-foot swath of bright red for a very short period of time," George said.
The concept gained some credibility when it was mentioned in the 2001 report by the authoritative Intergovernmental Panel on Climate Change, which cited it as a possible way to attack carbon emissions.
Small experiments "showed unequivocally that there was a biological response to the addition of the iron," the climate report said. Plankton used the iron to photosynthesize, extract greenhouse gases from the air, and grow rapidly. It forms a thick green soup of all sorts of carbon dioxide-sucking algae, which sea life feast on, and the carbon drops into the ocean.
However, the international climate report also cautioned about "the ecological consequences of large-scale fertilization of the ocean."
Planktos officials say that for every ton of iron used, 100,000 tons of carbon will be pulled into the ocean. Eventually, if this first large-scale test works, George hopes to remove 3 billion tons of carbon from the Earth's atmosphere, half of what's needed. Some scientists say that's overstated.
Planktos' efforts are financed by companies and individuals who buy carbon credits to offset their use of fossil fuels.
Man-made volcano
When Mount Pinatubo erupted 16 years ago in the Philippines it cooled the Earth for about a year because the sulfate particles in the upper atmosphere reflected some sunlight.
Several leading scientists, from Nobel Laureate Paul Crutzen to the late nuclear cold warrior Edward Teller, have proposed doing the same artificially to offset global warming.
Using jet engines, cannons or balloons to get sulfates in the air, humans could reduce the solar heat, and only increase current sulfur pollution by a small percentage, said Tom Wigley of the National Center for Atmospheric Research.
"It's an issue of the lesser of two evils," he said.
Solar umbrella
For far-out concepts, it's hard to beat Roger Angel's. Last fall, the University of Arizona astronomer proposed what he called a "sun shade." It would be a cloud of small Frisbee-like spaceships that go between Earth and the sun and act as an umbrella, reducing heat from the sun.
"It really is just like turning down the knob by 2% of what's coming from the sun," he said.
The science for the ships, the rocketry to launch them, and the materials to make the shade are all doable, Angel said.
These nearly flat discs would each weigh less than an ounce and measure about a yard wide with three tab-like "ears" that are controllers sticking out just a few inches.
About 800,000 of these would be stacked into each rocket launch. It would take 16 trillion of them, so there would be 20 million launches of rockets. All told, Angel figures 20 million tons of material to make the discs that together form the solar umbrella.
Artificial Trees
Scientifically, it's known as "air capture." But the instruments being used have been dubbed "artificial trees" — even though these devices are about as treelike as a radiator on a stick. They are designed to mimic the role of trees in using carbon dioxide, but early renderings show them looking more like the creation of a tinkering engineer with lots of steel.
Nearly a decade ago, Columbia University professor Klaus Lackner, hit on an idea for his then-middle school daughter's science fair project: Create air filters that grab carbon dioxide from the air using chemical absorbers and then compress the carbon dioxide into a liquid or compressed gas that can be shipped elsewhere. When his daughter was able to do it on a tiny scale, Lackner decided to look at doing it globally.
Newly inspired by the $25 million prize offered by Richard Branson, Lackner has fine-tuned the idea. He wants to develop a large filter that would absorb carbon dioxide from the air. Another chemical reaction would take the carbon from the absorbent material, and then a third process would change that greenhouse gas into a form that could be disposed of.
It would take wind and a lot of energy to power the air capture devices. They would stand tall like cellphone towers on steroids, reaching about 200 feet high with various-sized square filters at the top. Lackner envisions perhaps placing 100,000 of them near wind energy turbines.
Even if each filter was only the size of a television, it could remove about 25 tons of carbon dioxide a year, which is about how much one American produces annually, Lackner said. The captured carbon dioxide would be changed into a liquid or gas that can be piped away from the air capture devices.
jb
www.burgy.50megs.com
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Received on Fri Mar 16 10:50:37 2007
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