The source I used to obtain Earth's atmospheric methane proportion/concentration
is a graph on the http://yosemite.epa.gov website [I didn't write down the specific webpage], and requiring
Abode Acrobat Reader.
The graph slope indicated a concentration of CH4 "greenhouse gas" in Earth's atmosphere of about [GET THIS!] 1750 parts per billion, around the year 2000.

WOW! THAT'S HIGH!
Yea! I had difficulty that one myself.

Was the graph obtained from data gathered at Yosemite National Park? Or were the values a projection from a 1980's, 1990's study?
The write-up on the AAR didn't say.

Jacob

"This planet has a 100 percent mortality rate."