Iris hypothesis

The iris hypothesis was presented by Richard Lindzen in 2001. It is assumed that a higher sea surface temperature would result in tropical latitudes to a reduced formation of cirrus clouds and thus to an increased infrared radiation. According to Lindzen, the effect of negative feedback in the context of global warming dar. The warming effect of greenhouse gases would be greatly attenuated by the Iris effect; climate sensitivity is considerably lower than is commonly assumed.

The name of the hypothesis is selected based on the iris of the eye that is responsive to changing brightness with a variable opening of the pupil. Similarly, should for the Iris hypothesis an increase in the equatorial surface temperatures a " hole ", ie Reduction of cirrus cloud cover in these latitudes arise.

Climatologists, who tested the hypothesis found no evidence that she agrees. Measurement data from the Clouds and the Earth 's Radiant Energy System stand by in contradiction to the hypothesis, so that NASA literally writes: "Evidence Against the Iris Hypothesis ". Other researchers found an effect, but this was a positive and no negative feedback. An article by Roy Spencer from 2007 and a new publication from 2009, also from Richard Lindzen, support the hypothesis.