Buzz, my comment about the fraction - let me put it like this. I'm making the numbers up to show the relationships. If there were 100 tons of CO2 emitted 150 years ago, 45 tons stayed in the atmosphere. 150 years later, if 1000 tons of CO2 are emitted, 450 tons stay in the atmosphere. So if the rate of emission goes up, thepercentagethat stays in the atmosphere stays the same, but theamountvaries with total emissions.

Does that make more sense?