The Greenhouse Gas No One Talks About

Water in the atmosphere, in the form of the invisible gas water vapour, is the most powerful of greenhouse gases, yet it doesn’t get much public attention. In this article we’ll go back to basics and examine how and why that is.

Photo of the low sun just above a small treed island in a calm sea, the whole mostly obscured by thick fog
Water vapour is an invisible gas, but we can get a sense of its ubiquity when we encounter fog, which is tiny condensed water droplets. (Staff C photo.)