There have been a lot of things said here and I would like to address a few. Don’t get me wrong, I am not saying Al is right (I'm also not saying he is wrong) nor am I saying Global warming is a agreed upon fact, but if the temperature of the planet is going up, then that is global warming. As to the cause, good and important question.
1) Greenland's Ice Sheet is thickening at the interior at an altitude above 1500 meters. However it is decreasing in thickness at altitudes below 1500 meters
2) Actually there are other tropical or warm climate diseases that will move in if the temperature goes up enough, but there is a lot more to global climate warming than absorption of infrared by the atmosphere. The ocean itself has a lot to do with it as well.
3) And if you introduce enough fresh water from Glacial melt into a sal****er system it can affect this is a very negative was. Not to mention the sea life extinctions it will cause. There are multiple oceanic systems that will be impacted by introduction of fresh water in a very bad way. Also the increase of carbon dioxide in the atmosphere can have and is having a negative effect as well. Ocean's acidity does rise with increased CO2, but at a slow rate. But this is not a good thing particularly for oxygen production
4) Antarctic Ice Sheet thickening: The big question does this change marks the end of the retreat, or is it just a short-lived reversal.
5) Under sea Volcanoes causing the oceans to warm... sorry that's just wrong. The oceanic system is way to complex for that to be the reason, particularly on a global scale.
6) Planet and peoples resilience: There is a theory that the planet is self-correcting. However you really do not want it to do that, it would definitely prove that the planet is WAY more resilient than the people on it. But the next species to master the planet would probably greatly appreciate it.
7) Terrorism, Nuclear threat: Yes they are extremely important issues and are more than likely more of an immanent threat. But why can’t we work on both issues, I did not know working on one excluded working on the other.
But if one of the (I believe 7) volcanoes under Antarctica goes off, then you may have water front property in Southern Georgia… possibly cold possibly hot… I’m not sure; that much fresh water introduced into the Ocean will cause major climate changes.
Note: there are currently no signs of a Volcano in Antarctic becoming active. However if you remove enough of the ice it could be a possibility. Ice is very heavy and Glaciers put a lot of pressure on the ground they sit on.
My previous posts on this are here if any are interested.
http://www.martialtalk.com/forum/showthread.php?t=33965&page=7
http://www.martialtalk.com/forum/showthread.php?t=33965&page=8