[tjwilhelm]

Originally Posted by cowgirlup

...I have wondered if the planet was perhaps returning to the warmer climate it seems to have once had in the distant past.

Just something i wonder about...

Here's the theory that supports your musings:

The ancient earth WAS too warm to support land animals (human animals, included). At that time, the CO2 content of the atmosphere was much higher than it is now. CO2 truly IS a "greenhouse gas" -- it allows the short wavelength radiation from the sun to pass through and be absorbed by the earth's surface. In the process, this absorbed solar radiation is converted into heat energy at the earth's surface, and long wave infrared radiation is emitted by the earth, outward toward empty space...HOWEVER, the CO2 in the atmosphere tends to prevent this re-radiation of the absorbed energy, and heat energy is accumulated. More CO2 = more trapped energy. Less CO2 = less trapped energy.

As plant life flourished on the ancient earth, our quiet green friends -- fueled by the sun's energy -- continually extracted CO2 from the atmosphere, they held onto the carbon component (making it part of their plants' bodies), and released the oxygen component back into the atmosphere.

As the plants died, the carbon they had removed from the atmosphere remained in their dead bodies, which ultimately concentrated and fossilized, becoming coal -- the carbon that used to be in the ancient atmosphere was now trapped (sequestered) within the crust of the earth. Over many centuries, this ongoing process reduced the concentration of CO2 in the atmosphere, and as a result, the earth cooled and became hospitable to land animals.

Essentially, fossil fuels, like coal, have trapped ancient energy in the form of solidified carbon (chemical energy). When this coal is burned, this ancient energy is converted back into heat, and the carbon that was long ago removed from our ancient atmosphere is put back there, here in modern times. In essence, when we burn fossil fuels, we are re-creating our ancient atmosphere...an atmosphere that contributed to the earth's surface being inhospitable to animal life.

Whaddaya think, Cowgirlup?

[Ron Fontaine]

Very interesting discussion. Thank you to everyone who participated.