Sun causes ‘La Nina-like effect’ on earth August 28, 2009Posted by honestclimate in Discussions.
Tags: climate change, global warming
Sun causes ‘La Nina-like effect’ on earth
ABC, August 28, 2009
Changes in the sun’s radiation cause a small La Niña-like effect on earth, an international team has found.
They say this together with another process involving ozone in the upper atmosphere, amplifies the effect of the sun on earth’s climate.
Australian climate scientist, Julie Arblaster of the Bureau of Meteorology in Melbourne and colleagues report their findings in today’s issue of the journal Science.
“It’s a small signal but it does explain some of our climate variability,” says Arblaster.
Scientists have long known that more sunspots increase the amount of radiation that reaches the earth.
The total energy that reaches earth from the sun varies by around 0.1% across an approximate 11-year solar cycle, say Arblaster and colleagues.
But what has long puzzled researchers is that the influence of this variation on the earth’s climate has been more than two times greater than would be expected.
Arblaster and colleagues have investigated a number of theories as to why this is the case and think they may have solved the mystery.
“We’re trying to understand the mechanism of how this change in the solar output amplifies in the climate in terms of temperature and rainfall,” says Arblaster.
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