For those of you who sometimes find yourself thinking, "Gee, I wonder how much my lifestyle really impacts the environment", you should know that there are plenty of ways to find out. (For those of you who never think that, please humor me for a moment.)
The very first time I calculated my "ecological footprint", I did so through MyFootPrint.org. It's comprehensive and it takes into account things like climate and city size. It's also really annoying because no matter how good I think I'm doing, I still require at least two Earths every time.
If you prefer a little more flash when you're finding out just how wasteful you are, may I suggest the Consumer Consequences game by American Public Media. In this exercise, you get to create a character and pick a cute little neighborhood before you destroy the Earth. Great graphics, too....check this one out.
Believe it or not, the US Senate's committee on the Environment and Public Works has also come up with a Global Warming Footprint calculator of its own. It's a little simpler than the other two, and really only deals with transportation and household emissions. But, it is a good "starter calculator" for those who have not heard of an ecological footprint before. Also it makes it seem like the US Senate is not completely useless, which is encouraging.
Last but not least, I actually just found this amazing and elaborate calculator at Zerofootprint.net, by way of Facebook. It covers pretty much all of the bases, and the graphics are quite clear although the interface is a tiny bit confusing. What's great about the Zerofootprint Calculator is that you can actually customize it to fit your lifestyle, which can only result in a more accurate footprint. It's also collecting data from urban centers around the world (information here) to show how even the smallest actions can reduce your impact on the environment.
So, there you have it. You can't say you don't know how you are impacting global warming. Now if we could only figure out how to fix it....