Well, looking at it logically, coffee itself, as well as any other agricultural product, is actually CO2 neutral. Any CO2 that is released in the coffee bean cycle was taken from the atmosphere first. It is NET ZERO.
The only CO2 that could be attributed to coffee would be the distribution.
Hmm...if you have to boil the water, I guess that counts too.
I guess we have to be subsistence farmers now.