I can't help but note that a HUGE (up to almost a third) of the oxygen in the atmosphere is produced by the gigantic forests of the Taiga, up by, you guessed it, Greenland, most of Canada, and lower portions of Russia. These vast evergreen forests are one of the major things producing oxygen, not just algae.
Carbon is not just stored in treetrunks either. Not only that, chopping down a rainforest or anything of the equivalent would induce an environmental catastrophe that would quickly take away the advantages of doing so.
No, what you need to be worried about is the ocean. The ocean stores INSANE amounts of carbon, and those rainforests and cows produce an amount thats able to be absorbed by it. But the MILLIONS of TONS of CRAP we are pumping out each day is quickly taking its toll. The entire reason that global warming could be so sudden is because of this - if it gets too bad, the oceans will stop absorbing it - and start emitting it. In vast quantities. Everywhere (starting, theoretically, near south America). Bye bye planet.
There is a lot of evidence pointing to the fact that climate change is induced by us. It becomes starkingly obvious when you look at how the naturally produced CO2 is always absorbed and processed, somewhere, somehow, and usually converted and reused, even if its absorbed by the ocean (which you can think of the earth's backup plan). Our stuff? Its overloading not just isolated ecosystems, but the entire freaking PLANET! Our emissions have destabilized what was once a delicate balance. The backup plan, the oceans, are almost depleted of storage space. The instant the oceans stop inhaling, and start exhaling, we're screwed.
