What kind of plant could "save the world"?

Hemp. If we have a good replacement paper source then we can leave the trees alone and allow trees to perform their task of 'lungs of the earth'.

An algae that replaces all the algal populations we've lost and acts as a very effective carbon sink.

What Dino said, and Biggles answer is also good, I Hemp.

Most of the "lung" work done by trees is when they are building themselves - i.e. growing, which means harvesting trees and allowing new ones to grow is the best way of removing carbon from the atmosphere, not just leaving trees alone.

sunflowers definitely sunflowers

Diatoms are doing this right now. They are booming due to increased atmospheric CO2, and their shells accumulate at ocean floors. Earth knows how to take care of itself.

In reply to your reply to Dino: Not if you just go and burn the trees that you cut down.

In reply to your reply to me: But CO2 levels are still rising (whether you want to put it down to us or to natural processes). Earth may survive, but we may not.

An "im"-plant

What exactly is the optimum level of atmospheric CO2, and why?

For who or what?

For the planet. Since there is so much concern about the liberation of CO2 I assume there is some optimum level in the minds of those who believe we are somehow damaging the planet by adding more carbon to the atmosphere.

I go with hemp.

Of these, hemp is the most likely prospect, if it would allow us to save trees. And now, prepare for some amazing mental gymnastics: if hemp were legalized in the US, that would mean that attitudes towards cannabinoid plants in general had been relaxed, and that marijuana would be legalized shortly, if it hadn't been already. If people began smoking pot more often, they would all chill the fudge out, and that would *really* save the world!

A boglike Savage Garden filled with carnivorous snakelike traplike trumpetlike plants that ensnare only the stupid and inconsiderate digesting them in a slow painful manner.

Amen sister!

Dont know

Hemp of course. It's a great plant, but misunderstood by many.

Poison Ivy- Then everyone's back will get scratched!

Well, that depends what you mean by the "planet". The actual Earth isn't going to be all that concerned by any atmospheric conditions. The life on Earth on the other hand.....Some of it will be better off with higher CO2 rates, some of it will be worse off. Even if CO2 levels go through the roof, all life on Earth won't be wiped out. A lot of the animals and plants we're quite fond of, including ourselves, could be though.

I'm not sure what the optimum is for us - the one that keeps things pretty much the way they are, so that we don't lose any of the species that we rely upon.

I was so sure this was a KR survey...

the second one sounded cool.

hemp can also be substituted for fuel, which would be wonderful. Too bad our leaders are a bunch of sh-t heads and won't legalize it.

Assuming of course that there aren't species under strain already due to the carbon poor atmosphere. Since plants grow faster with higher CO2 levels, and require less water, and since all life other than autotrophs require plants to convert solar energy into usable forms, I fail to see how increasing levels of atmospheric carbon dioxide by itself could possibly have an adverse affect on any life. See http://www.co2science.org/journal/2000/v3n16b2.htm for more.

If CO2 increases result in rapid global warming, there is also doubt that habitats will not be able to cope. It took only 15 years for a coral reef off Java to regenerate after an erruption destroyed it. Green groups claim it takes hundreds of years. I remember seeing a feature on the Greenpeace website that showed a retreating glacier with a caption like 'evidence of habitat destruction'. I don't know about you, but I consider melting glaciers habitat creation.

I doubt very much that the pre-industrial revolution atmosphere was the optimum for life overall. That's just where it was at. Plants were already having difficulty with low CO2 levels making photosynthesis inefficient. I believe the atmosphere could do with far higher CO2 levels which will bring a boom in plant life and in all the insects and animals that directly or indirectly gain nutrients from plants. If CO2 levels go through the roof the place might look more like it used to, before almost all carbon was removed from the atmosphere by plants.

Super Sunflowers! That's a good idea! I'm stealing it. J/K.

Plants don't grow better and better at higher CO2 levels. There is an optimum level, after which their productivity begins to fall. When the CO2 level reaches a certain point, the plant will die.

Melting glaciers do destroy habitats, but they do also create new ones.

Well the optimum level certainly isn't the pre-industrial revolution level that green groups claim. Experiments used in the link I gave you used 700ppm, twice what the levels are now.

Algae!!!!

*hopes someone notices that she fought urge to be Miss Pedantic on this survey*

Large, beautiful flowers that provide medicines that cure things from allergies to cancer, and provide food for all.

I think the Soybean plant will save the world. Eventually it will fuel cars, you can make so many different food products with it.

an edible fungus that can also be cut into stiff insulating foam blocks which would be usable for construction

*really, really fighting Miss Pedantic urge*

*is defeated*

Aaaaaargh! Algae and fungi aren't plants!!!!

Phew.

Sorry, that had to come out sooner or later

a magical plant