I'm pretty sure man is the cause, but the reason isn't as simple as 'we're puttin more CO2 in the air" or anything so Algorish.
Mankind is too fuckin' big. That's the real reason.
No respectable scientists anywhere doubt that we've far exceeded the carrying capacity of planet earth. AGW is just the first of many shitstorms we are creating for ourselves from being this big.
We hurt the natural balance in many ways; mostly by killing the other living things on the planet that offset warming. Too much asphalt is one reason; it destroys the Earth's natural AC in urban areas. But I'll give you a better, more believable example:
A. We are eating too many fish.
B. Those meals of ours would have eaten things below them on the food chain.
C. Those less numerous ocean critters, like plankton and diatoms, would have resulted in a lighter-colored ocean.
D. Because the ocean accounts for the majority of groundcover on earth, the earth is now darker-colored and reflects less light.
E. More light NOT reflected away is turned into heat. Voila.
Shit like this is happening all over the planet. In our dirt, in our upper atmostphere, all of it. And yes, more carbon from factories and from more LIVESTOCK needed to feed us is certainly measurable too. We're changing too much stuff all at once.
Shit adds up! :angryfire:
For those of you who don't see how colder winters can be caused by global warming; read this short article:
Cold Winters Driven By Global Warming : Discovery News
It basically shows how the storms will naturally go further south in hotter weather... The overall surface average has without a doubt gone up throughout it.
Oh yeah, and for Rexabit's sad argument that global warming would save lives because "more people die from cold deaths each year than they do from heat deaths" -
Remember that a 1 degree Celsius increase in the global temperature won't be noticed by anyone but scientists... As they count the increased number of storms that kill far, far more people than both heat and cold do.
They certianly did in 2010. Just ask anyone in Russia or Pakistan. Even along the East Coast last February... Snowzilla was quite a freak occurrence but the books clearly show that freak occurrences are happening more and more lately... In roughly the same frequency as the global temperature is rising.