3. (15 points) Some people think that it is implausible that humans can be affecting the amount of C02 in the atmosphere because the atmosphere is so big and we are so small- The total mass of the atmosphere i_s very large about 5 X 1018 kg. But C02 is a fairly small fraction of this about 6 x 10'4 of its mass. According to the website on carbon footprints: the average amount of C02 produced by a person in the US is about 20 metric tons per person per year. (One metric ton is 103 kg.) If every person in the world produced this much C02 every year, how long would it take to increase the amount of C02 in the atmosphere by 20%? (This is oversimplied, but gives us a reasonable idea of whether it is at all plausible that human produced CD; can be signicant.) Be sure to clearly state your assumptions and how you came to the numbers you estimated, since grading on this problem will be mostly based on your reasoning, not on your