Just a few facts:
The Earth is not a static environment. Means: It -will- change.
The hole in the ozone is -not- getting smaller. Means: This last year is the biggest ever recorded.
A mini ice age occurred less than two hundred years ago. Means: They can happen without our help.
Greenhouse gasses help warm the Earth. Means: Keyword 'help'. They are not the only cause of global warming, but they are the one thing we can partially curb. I say partially, because CO2 is not the only, nor worst of the greenhouse gasses.
The sun is in an expanding cycle: Means: You are so screwed if you think getting rid of greenhouse gasses is going to stop global warming. The Earth -is- slowly going to get hotter, and there is nothing we can do about it.
The polar caps are melting. Means: Move inland, or get wet.
Humans are the most adaptable creature on the planet. Means: We will survive most changes in weather. Other creatures will not. extinction is a fact of life, folks. You can't save everything. See fact one.
Antarctica had a temperature spike way back when. Means: Nothing. It was a fluke in the weather pattern. Shall I go outside right now and say it never rains in Wisconsin because it did not rain today? Or that there is always six inches of ice on the river because that is what I just measured? Only a fool predicts the weather by one day. Weather is a huge and evolving creature that we can barely understand. You can only begin to understand it by looking at statistics encompassing years, centuries, or millennia. Anything else is just idiocy.
The moon is drifting further away from the Earth every year. Means: Unknown, but something with one sixth our own gravity moving away from us will have a profound effect. The tides will get weaker as well. Not to worry, the Moon moves away at less than four inches a year. Fact: The moon was six times larger in the sky in the time of the dinosaurs.
The Earth is slowing down. Means: Unknown. This is so much bigger than us that most can not comprehend what it might mean. Incidentally, one leading theory is that the Moon is what is robbing the Earth of its spin, and thus gives it a four inch boost further out into space. Want to know how? Look it up. I'll give you a hint. It has to do with the oceans.
Greenland used to be green. Means: See point one.
Bush has stripped the science budget for environmental studies. Means: If you can't see it, it must not be there. How scary is that? Sure, you can try to blame Congress, but guess who has the power of Veto. What you do not stop, you allow by default.
The permafrost in Siberia is melting. Means: First you must know exactly what a great deal of permafrost is made of before you can understand what this means. Permafrost is basically frozen biomassthat has built up for thousands of years. When biomass melts, it starts to rot. When it rots, it give off an insane amount of methane. Fact: Methane is a far more effective greenhouse gas than CO2. This is the cycle: Biomass melts and rots -> massive amounts of methane release, increase greenhouse effect, warming the Earth -> more biomass melts -> etc. Means: We can not stop global warming anymore.
The ocean floors are covered in methylhydrates. Means: Methylhydrates are basically a mixture of pure methane in a water crystal matrix. The cold and pressure of the ocean depths keeps it that way. If something were to disturb the cold currents, bad things can happen. Very bad things. Interesting fact: A release of methane from disturbed methylhydrates will sink any ship instantly. Fact two: There is a huge deposit of methylhydrates under the Bermuda Triangle.
The point of the last two statements is simple. They are both gigantic boulders balanced on a ledge. Once they begin to tip over that ledge, there will not be anything that can stop them. Doomsday for the planet? Who knows? You have to remember at one point the entire surface of this world was warm and tropical. You also have to remember that at another time, half the planet was covered in ice. No one will know how we are going to end up until we get there. It could be something rare could happen, and the Earth will continue its precarious balancing act... and stay relatively the same.
I would like to wrap this up by saying there are many other things to consider, such as the oceans getting saltier, the Earth tipping more on its axis, the effect of highways and cities on temperature, meteors, and many others. The biggest point is, we are simply not the masters of this world. Humans and human suffering really means nothing on the larger scale. With or without us, the world will go on, until our sun turns into a red giant in a few billion years…and swallows it.