  Based on observations and climate model results, it has been suggested that
the recent slowdown of global warming trends (climate hiatus), which took place
in the early 2000s, might be due to enhanced ocean heat uptake. Here we suggest
an alternative hypothesis which, at least in part, would relate such slowdown
to unaccounted energy reflected or reemitted by clouds. We show that the daily
cloud cycle is strongly linked to pacific decadal oscillation (PDO) and that
its decadal variations during the climate hiatus have an overall cooling
effect. Such an effect may have partially, and temporarily, counteracted the
greenhouse warming trends.
