2007-10-13 13:17:48 · 3 answers · asked by Anonymous in Environment ➔ Global Warming
Removing them is extremely difficult. Richard Branson has offered a 25 million dollar prize to anyone who can come up with a practical way to do it.
http://foundationcenter.org/pnd/news/story.jhtml?id=169300021
It's far better to keep them from being released in the first place. Here's a practical and affordable plan to do that.
http://www.spiegel.de/international/world/0,1518,481085,00.html
http://www.ipcc.ch/SPM040507.pdf
2007-10-13 13:24:13 · answer #1 · answered by Bob 7 · 3⤊ 0⤋
There's various schemes that have been suggested, some of them have already been trialed on a small scale level.
There's basically two approaches - one is the application of chemical processes and the other is the stepping up of natural processes.
Plants sequester carbon dioxide through the process of photosynthesis, if we were to increase the number of plants we would also increase their uptake of CO2. One of the problems is that when a plant or tree dies and degrades it releases the carbon again. An average tree for example will contain 2 or 3 tons of carbon but only for as long as it remains in it's natural state.
However, marine plants have the advantage that when they die they sink to the bottom of the ocean taking the carbon with them and this, over millions of years, forms carbon based rocks such as limestone or chalk.
Phytoplankton are tiny marine plants, they exist in vast quantities in some parts of the oceans and are visible from space as blue/green blooms. There are other parts of the oceans which are effectively sterile environments as far as phytoplankton are concerned but by introducing the correct nutrients the oceans can be made condisive to the spread of phytoplankton.
The nutrients in question being primarily iron and / or nitrogen. Tests have been carried out to seed parts of the ocean with iron filings or fertilise them with nitrogen from urea. These early tests have been reasonably successful (more so the nitrogen based schemes) and if implemented on a large scale they could remove billions of tons of CO2 from the atmopshere each year.
The same principle also applies to algae and similar tests have been conducted.
There's several variations on the chemistry approach to carbon sequestration but they all work on the lines of a chemical reaction involving carbon dioxide. One method which uses sodium hydroxide does so in 'atomised' format, the droplets react with atmospheric CO2 to produce sodium bicarbonate. Calcium oxide is then added so the sodium hydroxide can be recovered and reused, the residual calcium carbonate can be heated and the calcium oxide also recovered for reuse leaving behind CO2 for disposal underground. This is the approach favoured by Dr David Keith.
A similar scheme using sodium hudroxide has been proposed by Prof. Klaus Lackner. The byproducts of the reaction would be used to make synthetic petrol and / or synthetic diesel.
These white papers have a lot more info...
http://www.netl.doe.gov/publications/proceedings/01/carbon_seq/7b1.pdf
http://www.centre-cired.fr/perso/haduong/files/Keith.ea-2005-ClimateStrategyWithCO2CaptureFromTheAir.pdf
2007-10-13 13:43:07 · answer #2 · answered by Trevor 7 · 3⤊ 0⤋
The only problem with marine plants (and animals because they are made of carbon too) is that they will sink and in millions of years after they turn into oil some idiot will figure out how to burn it all and release all the carbon again.
2007-10-13 22:14:55 · answer #3 · answered by smaccas 3 · 0⤊ 0⤋