Not today, but the trend is worrying, especially if the rate increases. What will this look like in 50 years? 1,000?
``` Should we be concerned that the atmospheric oxygen supply is declining?
This point was addressed in an article by Broecker (Science, Vol. 168, 1537-1538, 1970). Although written many years ago, the basic point made by the article remains valid. The maximum potential loss of O2 from fuel burning, when fossil fuel reserves (mostly coal) are exhausted is only a few percent of the atmospheric burden. Since even this loss will take many centuries to materialize, it's hard to see this as high on the list of possible environmental concerns. ```
I am sure there are some weird feedback loops we are going to see in the next century or two, that aren't yet considered an issue.