In 2001, white house officials from the President's Climate Change Technology Program called a couple dozen scientists in to think of ways to fight
global warming. This meeting came in response to George Bush pulling out of the Kyoto Treaty a few months earlier. Since reducing emissions to the
standards of the Kyoto Treaty was out of the question, the scientists decided to devise ways to "re-engineer Earth" in a sense by building things
such as giant fields of filters, or machines that would pump CO2 into underground saline aquifiers or subterrnaean caves. The goal in mind for each
one of these ideas is to store and remove CO2 from the atmosphere to cool the earth. In this article by Popular Science, 6 different methods of
removing the CO2 are discussed as well as the benefits and risks, and one device has already been built.
1.) The first method involves storing CO2 underground. 5,000 tons of liquid CO2 is pumped 4,000 feet underground every day, and in addition to being
stored, the CO2 is used to drive oil out of rock. The CO2 is injected with water into a subterranean cavern deep beneath the Earth. By 2033, this
project will end up storing 25 million tons of CO2, which is akin to taking 6.8 million cars off the road. There's another idea to trap CO2 into
saline aquifiers which can store 200,000 Gigatons of CO2 which would last us awhile considering that humans produce 28 Gigatons per year. The
pressurized CO2 should be kept indefinately, but there is worry that engineers could accidentally depressurize the supercritical CO2. It could also
leak into fissures into basments and silently kill many people.
2.) Another idea is building a field of giant filters 200 feet high that act like flypaper to trap CO2. Sodium hydroxide and calcium Hydroxide are
pumped through the filters and bond to the CO2. Although a single filter could bond 90,000 tons of CO2 a day, you would need an area of scrubbers the
size of Arizona to trap all the CO2 added to the air by humans. There is also the ironic situation of having to use fossil fuels to strip the CO2 from
the chemicals that bond to it.
3.) Fertilizing the ocean with iron is a very cheap, very feasible way to get rid of CO2, but might carry the risk of killing all marine life
In 2002, a group of scientists dumped 6,000 lbs of iron into the ocean and watched what happened. Oceanographer John Martin thought that the reason
the Southern Ocean was anemic was because it was devoid of iron: "Give me a half tanker of iron, and I'll show you an ice age". The result was a
colossal bloom of CO2-absorbing plankton. It's a very cheap way to get rid of CO2, but the plankton might also devour other nutrients that are
essential for marine life, and stelilize the ocean.
4.) Turning CO2 to stone is another option that is relatively cheap, feasible, and carries a low risk. "The Grand Canyon is one of the largest carbon
dioxide repositories on Earth. Hundreds of millions of years ago, a vast sea covered the land there. The water, rich in carbon dioxide, slowly reacted
with other chemicals to create calcium carbonate, or limestone—the pinkish bands striping the canyon walls today." Nature takes a painfully slow
time converting CO2 to stone, but by using chemicals like ovaline, CO2 can be transformed into calcium carbonate. According to the article, a single
mineral carbonation plant could carve out an entire mountain, but replace what it took with the calcium carbonate. The problem is the $70 pricetag to
get rid of 1 ton of CO2, and the fact that fossil fuels must be used to heat up the CO2 in the process.
5.) Cloud-seeding yachts are another way to cool down the Earth. The yachts would pump salt into the air to make more droples form in clouds, making
them whiter, and therefore more reflective. Boosting the reflectivity of just 3 percent of maring stratocumulus clouds would curb global
, but ejecting salt particles in an area with a drought could actually hinder the formation of clouds. You can't create clouds by ejecting
6.) The last option is also a last-ditch effort if all else fails. It's extremely unfeasible and outrageously expensive, and would involve making a
mirror spanning 600,000 square miles to reflect 1% of solar radiation. It would cost nothing to maintain, and all that people would see is a small dot
in the sun, but the price tag and engineering make it hard to build.
Sorry of this is in the wrong section. It's technology and has to do with the earths climate so I'm not sure which forum it would be better off in.