That is very interesting data, and the spike correlates roughly to my lifespan. Do you suppose I am too flatulent? 🙂
Seriously, it is obvious that something has changed dramatically. I am not a scientist, but my first thought was that to have that much impact there must be multiple causes and factors at play here. Factors that are natural and factors that are man-made. I don't pretend to profess what they all are, but I can think of a few to check out for possible inclusion into the equation. Examples might be geologic causes, population growth, destruction of forests and other natural sources of oxygen and users of CO2, animal populations (not just cows fart; take a horse-and-buggy ride), etc.
I try to be conscious of my own actions but this problem is a global problem. I believe we should do our best and let the rest of the world regulate and police themselves. There is no sense in economically destroying this country when we are such a minor part of the problem. Just my opinion.