But all in one direction. The much larger natural fluxes go in both directions. The ocean used to be a net source of CO2, particularly with the warming from Little Ice Age. Now it is a net sink of CO2 and absorbs about 1/2 of manmade CO2.
Restrictions upon theusage of fossil fuels can therefore reduce CO2 emissions by only one or two percent
Probably a bit more, but at a large economic cost. There is a distinct correlation between the economic downturn and our decreasing emissions.
Life can literally eat Carbon dioxide faster than himans can emit Carbon dioxide, despite the scaremongering claims to the contrary. If anything, the Earth needs more atmospheric Carbon dioxide to prevent the shutdown of photosynthesis in the Plant Kingdom essential to the survival of Life on the Earth as the planet’s atmosphere naturally continues to be thinned by the Solar winds.
Right now the ocean is mostly eating CO2. Plant life can eat a lot too, but only if we increase its area (e.g. rainforests). Your last point is good and worth emphasizing. Until we started raising the level of CO2 from roughly 280, the planet was literally CO2 starved. The evolution of grasses was the final nail in the CO2 coffin since they are so adept at sucking CO2 out of a CO2-starved atmosphere. We are currently within a long term ice age and a return to glacial conditions was inevitable. Even another Little Ice Age would have made it extremely difficult to feed mankind. But those fears are over for now.
We’re already in the beginning stage of a little ice age in the current Solar minimum. Temperatures are about to get much colder for about a thirty year cycle. When the current inter-glacial may end and the next glacial period resumes is of course not known, but recent research indicates it takes barely a decade to plunge into the deep freeze of one of these glacial periods once it does begin. It remains to be seen how cold the current Solar minimum will take us in the next 10 to 30 years, but past experience suggests the current Solar in activity is somewhat comparable to the cold weather experienced during the 19th Century Dalton Minimum and the much colder Maunder Minimum of the 15th to 18th Centuries.
Anthropogenic sources of Carbon dioxide emissions to the atmosphere simply cannot make a perceptible dent in these conditions, even if there were no humans around to provide such inluence.