New research shows Earth's clouds are getting little lower,
about one percent on average. According to scientists this
indicates that something quite important might be going on. The
results have potential implications for future global climate.
Scientists at the University of Auckland in New Zealand analyzed
the first 10 years of global cloud-top height measurements (from
March 2000 to February 2010) from the Multi-angle Imaging
SpectroRadiometer (MISR) instrument on NASA's Terra spacecraft.
The study, published recently in the journal Geophysical
Research Letters, revealed an overall trend of decreasing cloud
height. Global average cloud height declined by around one
percent over the decade, or by around 100 to 130 feet (30 to 40
meters). Most of the reduction was due to fewer clouds occurring
at very high altitudes. Lead researcher Roger Davies said that
while the record is too short to be definitive, it provides a
hint that something quite important might be going on. Longer-
term monitoring will be requir