The earth has gone massive changes since it was a burning mass of molten rock that would instantly kill any human that stepped foot on it. Asteroids, super volcanoes and a collision with a Mars sized planet that created the Moon are a small sample of the highlights. The atmosphere has changed as much as the land. Oxygen was a trace gas before all those pesky plants started "breathing" and I believe there was a much much higher CO2 rate.
The earth is not some precious snow flake forever frozen in time less it be destroyed by a single human breath. It is a constantly changing "living" organism in its own way and even if CO2 became 10% of the atmosphere it would be nowhere near the top 100 worst things to have occurred to the planet.
The Sun is the primary source of heat for this planet. If the Sun goes nova we burn in fire, if the sun stops without going Nova then we die by ice and a 100% CO2 atmosphere wouldn't stop the cold. The Sun may well be a variable star and even if it does meet the scientific definition, it is certainly nowhere close to a constant output. A 4C increase in temperature is merely solar spring and a 4c decrease is autumn. For those who argue that these events happen over millennia not years, we simply don't have yearly reading from any previous ice age to check.
I'll leave you with this quote from Michael Crichton that sums my thoughts up in a much more elegant way.
http://www.goodreads.com/quotes/166244- ... ing-vanity
Mark
The earth is not some precious snow flake forever frozen in time less it be destroyed by a single human breath. It is a constantly changing "living" organism in its own way and even if CO2 became 10% of the atmosphere it would be nowhere near the top 100 worst things to have occurred to the planet.
The Sun is the primary source of heat for this planet. If the Sun goes nova we burn in fire, if the sun stops without going Nova then we die by ice and a 100% CO2 atmosphere wouldn't stop the cold. The Sun may well be a variable star and even if it does meet the scientific definition, it is certainly nowhere close to a constant output. A 4C increase in temperature is merely solar spring and a 4c decrease is autumn. For those who argue that these events happen over millennia not years, we simply don't have yearly reading from any previous ice age to check.
I'll leave you with this quote from Michael Crichton that sums my thoughts up in a much more elegant way.
http://www.goodreads.com/quotes/166244- ... ing-vanity
Mark