> the ambient level of co2 in the atmosphere is approximately 400 ppm. at 100 ppm of co2 the rate of photosynthesis would be stopped completely. at 150 ppm the plants begin to respire, and photosynthesis is stopped. daily reminder that everything on earth dies below 200 ppm co2 and that injecting into the atmosphere a 100 ppm buffer over pre-industrial levels is a good idea.
Canada