Hundreds of thousands of years ago, New Mexico (and parts nearby) were completely covered by ocean water. Today, they are quite obviously many, many miles from the ocean. We know that they were under water because of the rock formations and even the fossilized remains of sea creatures that still turn up every so often. Humans were not here to effect the climate change that must have happened to cause the changes that we see. I don't know how much impact humans have had on the overall Earth's climate, but I do know that we've only accurately been able to chart the weather for about 100 years. For a planet that scientist tell us is millions of years old, this would be like you trying to predict what the weather will be like tomorrow by using a fraction of a second of last Friday's weather. "Well, it was 50 degrees here last Friday at 10:04 and 58 seconds, so that means tomorrow, it's going to be 90 degrees." We simply don't have the ability to tell. Once we've charted the weather regularly for several thousand years, then we might be able to make more accurate predictions. (And who among us has not heard a meterologist say "we'll get snow/rain, and it'll be this much" and not a flake or drop fell, or vice versa "it'll be warm and sunny" and you find yourself freezing or out in the rain without your umbrella.)
And as another person posted, in the 1970's, the scientists of the era assured us that we were entering an ice age and that our natural gas resources would be completely extinguished by the late 1990's.
Astronomers know that the sun is a major cause of our climate. A huge storm on the sun developing rapidly could destroy the earth in a very short time. All things considered, I'd say the impact of humans is far less than the impact of the sun, of volcanoes, of continental drift, etc.
-Dorothy (LadyZolt)
