There's quite a bit of crap thinking about Global Warming going on. I thought I'd jot down a few thoughts.
1. The worst case scenario
Almost everyone agrees that oil is the results of lots of dead plants being heated and pressurized underground for a long period of time. I'm sure there are complications in there, but those are the basics.
So, what can we expect the world would look like, if all that oil is returned to the atmosphere?
We already know: It'll look largely like the world before the dinosaurs. Take a look at this map of the Early Devonian period.
It's kind of hard to judge how much land is actually under water - it looks like it's about 1/4 - 1/3 of the present land mass.
That's pretty much the worst case.
A few things to note: the climate back then was quite conducive to life. The most life-intensive areas in the world are the continental shelves - those would be enormous compared to nowadays. Additionally, there should be quite a bit of rainfall - enough to grow all the plants necessary to make the oil, not to mention support all of the dinosaurs.
As far as diversity of life, if the worst case scenario happened and the sea levels rose that much, most of the large animals (not under human care) would probably die out. Large animals generally have long life-spans and hence slow evolutionary cycles. Also, most animals which live in highly specialized niches or depend on complex interactions between many different species will probably have a difficult time surviving.
Warmer temperatures will favor cold-blooded animals over mammals.
2. Carbon Sequestration
I hear about this one all the time. We need to develop the technology to sequester carbon.
Well, we already have it. It's been around for far longer than humans have been alive.
It's call plants.
Plants are essentially composed of solid atmosphere. By dry weight they are about 50% carbon (depending on the relative concentration of lignins and cellulose) - significantly more concentrated than carbon dioxide's 15.8%.
The interesting thing is that we, as a nation, have already been engaging in carbon sequestration at a massive scale. In New York's Fresh Kills landfill alone, there is roughly 10 million tons of carbon (not carbon dioxide, carbon) being stored in the form of paper.