To understand how cloud feedback might work, you
have to understand some facts about clouds:
(1) Clouds absorb radiation in the infrared, and
therefore have a greenhouse effect on the climate.If
you puta cloud high in the atmosphere, it will have a
stronger greenhouse effect than if you put it low in the
atmosphere.
(2) Clouds reflect sunshine back to space.So more
clouds means less sunshine for earth.If you put a
cloud high in the atmosphere, it will reflect about the
same amount of sunshine as if you put a cloud low in
the atmosphere.