text: On a sunny day in winter with all the windows closed green house operators must pump carbon dioxide into the green house because the plants absorb the gas as a nutrient and turn it into carbon fibre (human food).   If the consumed gas is not replaced the plants stop growing.  They are, in effect, starving.  As the world's population  continues to increase and more food is required to feed them, more carbon dioxide, not less, will be required.