Clouds to cool the earth
Sydney: Analysis of lower cloud levels over the past decade has thrown up hints of a cooling mechanism that may be key to the planet's climate, a study reveals.
The analysis of this data from the NASA Terra satellite reveals that the global average cloud height declined by around one percent over the decade, or around 30 to 40 metres.
"This is the first time we have been able to accurately measure changes in global cloud height, and it provides just a hint that something quite important might be going on," explained Roger Davies, professor at the University of Auckland, who co-authored the study with Matthew Molloy.
A consistent reduction in cloud height would allow the earth to cool to space more efficiently, reducing the surface temperature of the planet, Davis was quoted as saying in the journal Geophysical Research Letters.
This may represent a "negative feedback" mechanism -- a change caused by global warming that works to counteract it, said a university statement.
"We don't know exactly what causes the cloud heights to lower, but it must be due to a change in the circulation patterns that give rise to cloud formation at high altitude," said Davies.
Until recently however, it was impossible to measure the changes in global cloud heights and understand their contribution to global climate change.
"For the first time we have been able to accurately measure the height of clouds on a global basis, and the challenge now will be to incorporate that information into climate model," added Davis.