Global warming is shifting Earth's clouds     

The reaction of clouds to a warming atmosphere has been one of the major sources of uncertainty in estimating exactly how much the world will heat up from the accumulation of greenhouse gases.

Some changes will enhance global warming and some will decrease it.

The pattern of cloud change we see is the pattern associated with global warming, said the Scripps Institution of Oceanography.

While clouds are a key component of the climate system, helping to regulate the planets temperature, their small scale makes them difficult to accurately represent in climate models.

Satellite observations cannot be used to look for trends because they come solely from weather satellites, which are not geared to producing consistent, long-term records. In addition, some satellites have been replaced over time or have changed their orbit, which give false trends.

Such changes reinforce global warming: There is less solar radiation at the high latitudes near the poles, so as clouds shift that way, they have less radiation to reflect back to space. High cloud tops mean that more of the radiation that is absorbed and re-emitted by Earths' surface is trapped by the clouds