Will the atmosphere run out of CO2?

[dav2008]

I watched a program on some public broadcast channel where a professor from a university detailed the possible ends of the earth.

One of them (from what I recall) had to do with lowering CO2 levels in the distant future. The lack of CO2 would eventually kill off all plant life.

I tried searching the internet for a more detailed explanation but I couldn't find much as most searches turned up global warming pages. Does anybody know about the fate of Earth's atmosphere?

 

[Astronuc]

Based on the discussion of global warming these days, it would seem that there is an abundance of CO₂.

What is the argument for the loss of CO₂?

 

[dav2008]

That's what I'm wondering: what is the reason behind it?

Obviously in the short term CO2 levels are rising, however I am talking tens or hundreds of millions of years into the future.

 

[russ_watters]

That's what I'm wondering: what is the reason behind it?

Obviously in the short term CO2 levels are rising, however I am talking tens or hundreds of millions of years into the future.

Well didn't the program say why? Its a little hard for us to read the minds of the guys who wrote the show...

In any case, there is no reason I can think of why the Earth would run out of CO2.

 

[Andre]

Yes there have been theories about that. My guess is that all the carbon would eventually would disappear into the Earth crust either as fossil remains of life (peat - coal) or as limestone due to chemical rock weathering.

Some of that carbon returns as magma heats up limestone and decomposes it into CaO and CO2 emitted by volcanoes but that's only a small part.

The only possiblitly to recycle the fossile carbon is human activity: mining and oil drilling.

So in the end those horrible oil companies are saving the world from becoming a barren lifeless desert.

 

[Gonzolo]

Don't Mars and Venus have plenty of CO2?

 

[Phobos]

Don't Mars and Venus have plenty of CO2?

Yes, the atmospheres of Venus & Mars are mostly comprised of CO2 (over 90% for both I think). Venus' atmosphere is incredibly thick whereas Mars' is very thin.

 

[dav2008]

Well didn't the program say why? Its a little hard for us to read the minds of the guys who wrote the show...

In any case, there is no reason I can think of why the Earth would run out of CO2.

The reason I'm posting here is because I don't remember why.

I thought it might be a common scenario that people know about. I'll see if I can catch the show again. I think they replay it once in a while.