Clouds could be victim of climate change
It appears that increasing global temperatures will reduce cloudiness,
which will, in turn, lead to even more heating.
There has been a great deal of debate over whether global warming will lead to an increase in cloudiness – which could slow warming by reflecting the sun’s rays – or cause clouds to dissipate, thereby accelerating warming.
Researchers Amy Clement of the University of Miami and colleagues used 50 years of visual observations from ships and data collected from weather satellites to investigate patterns of cloud formation over seas of varying temperatures. They found that over the northeastern Pacific, low-level stratiform clouds appeared to be less extensive over warmer waters. Such a pattern implies the presence of a feedback loop whereby the cloud loss allows the oceans to heat up, which then causes further dissipation.
‘These are subtle changes that take place over decades,’ said Clement. ‘But it’s indicative of a vicious circle.’ Clement believes that higher temperatures cause water to rise higher into the atmosphere, creating upper-level clouds at the expense of low-level clouds. These higher clouds, in turn, trap more heat, further boosting the positive feedback.
The findings, published in Science, should help to improve the accuracy of climate models.
September 2009
There has been a great deal of debate over whether global warming will lead to an increase in cloudiness – which could slow warming by reflecting the sun’s rays – or cause clouds to dissipate, thereby accelerating warming.
Researchers Amy Clement of the University of Miami and colleagues used 50 years of visual observations from ships and data collected from weather satellites to investigate patterns of cloud formation over seas of varying temperatures. They found that over the northeastern Pacific, low-level stratiform clouds appeared to be less extensive over warmer waters. Such a pattern implies the presence of a feedback loop whereby the cloud loss allows the oceans to heat up, which then causes further dissipation.
‘These are subtle changes that take place over decades,’ said Clement. ‘But it’s indicative of a vicious circle.’ Clement believes that higher temperatures cause water to rise higher into the atmosphere, creating upper-level clouds at the expense of low-level clouds. These higher clouds, in turn, trap more heat, further boosting the positive feedback.
The findings, published in Science, should help to improve the accuracy of climate models.
September 2009
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