What potential effect could man be having on global temperatures?

The mean global temperature is ~14 °C which is 287 K. The increase in the earth's temperature due to the greenhouse effect is thought to be about 33 °C (= 33 K).

The contribution to the greenhouse effect by water including water vapour and clouds is probably 80-90%; CO₂ 5-10%; and other gases 5-10%.

The annual production of CO₂ from all sources is estimated at 200 Gtonnes. Man's input is about 7 Gtonnes. I have graphed this to show visually man's role.