Relative importance of carbon dioxide and water in the greenhouse effect: Does the tail wag the dog?

Writing in the Journal SCE, Demetris Koutsoyiannis of the Department of Water Resources and Environmental Engineering of the National Technical University of Athens assesses the relative importance of carbon dioxide and water vapour in the greenhouse effect. 

His conclusion?

... that the contribution of carbon dioxide is 4% – 5%, whereas water and clouds contribute  87% – 95%.

That carbon dioxide has only a minor effect is confirmed by the  hardly discernible effect on global temperature of the recent, more than one third increase in atmospheric CO₂ concentration from 300 to 420 parts per million.

That doesn't mean that we should not care about the effects of human activity on the composition of the air we breath. But it does mean that because The New York Times, The Globe and Mail, or The Guardian have been telling you for years that life on Earth will soon be Hell due to carbon emissions, does not mean that what they say is necessarily so.