MEMORANDUM THE WHITE HOUSE WASHINGTON September 17, 1969 FOR JOHN EHRLICHMAN As with so many of the more interesting environmental questions, we really don't have very satisfactory measurements of the carbon dioxide problem. On the other hand, this very clearly is a problem, and, perhaps most particularly, is one that can seize the imagination of persons normally indifferent to projects of apocalyptic change. The process is a simple one. Carbon dioxide in the atmosphere has the effect of a pane of glass in a greenhouse. The C02 content is normally in a stable cycle, but recently man has begun to...