L K Day wrote:Historically the earth's atmosphere has contained approximately 1/33rd of one percent C02. Today, due to man's activities, it is approaching 1/25 of one percent C02. This is supposed to produce a dramatic climate change? Really? Still looks like trace amounts of C02 to me. After all the atmosphere is still 99.96% compounds other than C02. I think I can see why a significant number of distinguished climatologists reject current global warming theory.
The atmosphere is less than 1/500th of one percent ozone. So why are we so worked up about the ozone layer? How can it possibly matter if it's so small?
The problem, in short, is not the absolute concentration of gases, but their efficiency to absorb radiation. Ozone is very very good at absorbing ultraviolet (UV) radiation (the harmful part of the sun's radiation which causes skin cancer, increased genetic mutations, etc), so we need that tiny bit of ozone up there.
By the same token, CO2 is very very good at absorbing infrared radiation, particularly at wavelengths that other atmospheric gases don't absorb. And so it prevents that energy from leaving the earth. When the amount of sunlight coming in is balanced by the amount of infrared radiation that is emitted by the earth to outerspace, then the temperature remains in balance. As we put more CO2, more of the infrared radiation will be absorbed and will not be transmitted to space. Thus the equilibrium temperature of the earth will go up.
That CO2 is a greenhouse gas is not in dispute by *any* climatologist or scientist who knows anything about the influence of atmospheric composition on global mean temperature. In fact, I don't believe any climatologist has disputed this for over 50 years, arguably 100 years. What questions remain are exactly how much warming will occur due to anthropogenic greenhouse gases, how quickly that warming will occur and how big of an impact that will have on the human population, particularly in under-developed countries, and on other species.