EPA unveils first rules on carbon dioxide storage

[phantom power]

WASHINGTON - The Environmental Protection Agency wants to make sure curbing global warming doesn't contaminate drinking water.

In its first regulations on the burial of carbon dioxide underground, the EPA on Tuesday unveiled measures to protect drinking water from the gas behind the bubbles in carbonated beverages. The fledgling technology, known as carbon sequestration, is critical to reducing carbon dioxide released into the air from coal-fired power plants, one of the country's largest sources of the greenhouse gas.

http://news.yahoo.com/s/ap/20080715/ap_on_go_ca_st_pe/epa_carbon_storage_3;_ylt=AownKrfR9Z4PjQrpLGThRe5rAlMA

[Howzit]

1. How much CO2 can be sequestered before breathable oxygen levels start to fall?

O2 makes up 21% of the atmosphere, while CO2 is 0.035%. Taking CO2 out of circulation would prevent plants from using it and recycling the O2. It would be a while, but if all the CO2 from coal powered power stations were buried, how long before the atmospheric O2 levels start to dip noticeably?

[phantom power]

2. I think I see what you're getting at, but that's not a problem.

If, for example, you removed all the CO2 from the atmosphere, that would be bad.

Nobody is going to do that. Nobody, in my opinion, is going to sequester any useful amount of CO2. But either way, nobody intends to sequester too much of it. The goal is to reduce CO2 to some historic normal. Say, the level circa the signing of the declaration of independence.

[kristopher]

4. Interesting question

Howy, this is the second time I've noticed you ask this question. I thought you weren't serious the first time, but seeing that you are, I'll try and answer.

Another way of looking at CO2 is to measure its ratio to all other gases, as in CO2 is X parts per million. There is a range within which our species has made its home. We are now outside that range and climbing at an extremely fast pace.

Essentially there are two different systems we are talking about: the biologic system and the geologic system. There is a cyle in both systems: CO2 is released into the air and it is removed from the air. The the model of interdependence between plants and animals you have in mind is based on the biological cycle. Then there is the geological cycle where things like volcanoes and naturally dissolving deposits of exposed calcium based rock release CO2 that is "new" into the biosphere. This is also an ongoing process. Acting to achieve a balance to this is, for example, CO2 that is absorbed by the ocean where through various mechanisms it ends up getting buried in the seabed for millions of years. (The oceans, you should recall, are part of our bioshpere, so until it is removed from the ocean and permanently buried, it really isn't geologically sequestered.)

What has gone wrong is that our presence has changed the balance that existed before we became so able to manipulate our environment. The rate we are digging up and consuming fossil fuels has taken us out of that range were we (and most other life on the planet) have developed.

There is zero chance that through carbon sequestration efforts we will move back down into that "safe zone" and then through it and come out the other side. You don't need to worry about that particular problem.

However, what you might want to consider to put on your schedule to contemplate worrying about is that rising greenhouse gas concentrations will start a cascade of changes that we have no hope of controlling. This cascade has happened a couple of times before and both times a very large percentage (95% at the Permian Triassic boundary) of life on this planet died off because the planet got so hot. Now, of course that isn't an overnight event, so if you are only concerned about what happens in your lifetime, perhaps you'll want to look into the effects that "minor" warming is expected to have on war, famine, drought and competition for resources.

Some good links to reputable climate science information are included for your convenience:

http://www.earthportal.org/

http://www.ucsusa.org/

http://www.realclimate.org/

[Howzit]

8. Thanks. Perhaps you would like to comment on post #6?

[NickB79]

5. Well, all the CO2 from coal plants WAS buried for hundreds of millions of years

Until humans began adding it to the atmosphere less than 200 years ago.

Removing every last molecule of CO2 derived from burning coal, oil and natural gas in the past 200 years would have almost no impact on atmospheric oxygen concentrations.

Nature sequestered that quantity of CO2 long before humans arrived, and life on this planet did just fine without it.

[Howzit]

6. Good point, but we need to parse words carefully

The problem stems from lazy speaking leading to lazy thinking. "Carbon sequestration" is a misnomer, potentially resulting in confusion between carbon dioxide (product of combustion) and hydrocarbon compounds (fuel).

Coal is mostly carbon combined with significant hydrogen, but very little oxygen. As such, coal IS sequestered carbon (and hydrogen), but cannot be considered as sequestered CO2 - yes, the plants in coal removed CO2 from the air, but this is not the same as taking actual CO2 gas and burying it in millions of gas bottles or rock chambers - the subject of the OP. Coal does not take O2 out of circulation to form CO2 until it is dug up and burned.

If for argument's sake, one does consider coal as natural CO2 sequestration, cannot one extend the idea further? If coal is formed of plants that converted CO2 from the air and H2O from the ground into hydrocarbons, doesn't the CO2 from coal "belong" in the air, and by burning it, isn't man simply putting it back into circulation? As coal deposits on earth are huge, an equivalent mass of CO2 used to be in the air before the plants that make up the coal lived.

I know coal took a long time to form from buried plants, but does anyone know over what time frame the plants lived, at what rate they took CO2 out of the air, and what the CO2 levels where when the plants lived that are coal today? I agree that if we burn coal at a higher rate than it formed, CO2 levels will increase faster than they dropped when the plants grew and were buried. Do we know what the natural level of CO2 was before man came on the scene? How far back should one go in history to find the "ideal" CO2 level? Why not go back millions of years, to the time of the plants that are coal today?

What buried such a vast mass of plants in contiguous shelfs to form coal? Was it a comet strike kicking up a massive "dust cloud" that then fell and entrapped the plants (and animals)? Plants tend to decay and have their hydrocarbons oxidized by bacteria and fungi unless they are cut off from the atmosphere.

[XemaSab]

3. Here's the meat of the article:

"While carbon dioxide in water itself isn't a problem — think Perrier or Diet Coke — too much of the benign bubbles can turn water slightly acidic, and leach toxic heavy metals and other contaminants out of the surrounding rock and into water supplies, according to scientists. Injecting carbon dioxide underground can also push other pollutants, such as saltwater, into underground aquifers."

I'm also guessing that the CO2 won't be perfectly pure, cause what's the point in scrubbing 100% of the sulfur, nitrogen, or mercury out of something you're going to bury? :shrug:

[NNadir]

7. They may as well regulate highways on Saturn's moon Titan.