http://news.bbc.co.uk/2/hi/science/nature/4171591.stm
We are all seeing rather less of the Sun, according to scientists who
have been looking at five decades of sunlight measurements.
They have reached the disturbing conclusion that the amount of solar
energy reaching the Earth's surface has been gradually falling.
Paradoxically, the decline in sunlight may mean that global warming
is a far greater threat to society than previously thought.
The effect was first spotted by Gerry Stanhill, an English scientist working
in Israel.
Comparing Israeli sunlight records from the 1950s with current ones, Dr
Stanhill
was astonished to find a large fall in solar radiation.
"There was a staggering 22% drop in the sunlight, and that really amazed
me."
Intrigued, he searched records from all around the world, and found the same
story almost everywhere he looked.
Sunlight was falling by 10% over the USA, nearly 30% in parts of the
former Soviet Union, and even by 16% in parts of the British Isles.
Although the effect varied greatly from place to place, overall the
decline amounted to one to two per cent globally every decade
between the 1950s and the 1990s.
Dr Stanhill called it "global dimming", but his research, published in 2001,
met a sceptical response from other scientists. It was only recently, when
his conclusions were confirmed by Australian scientists using a completely
different method to estimate solar radiation, that climate scientists at
last woke
up to the reality of global dimming............
Jan Rasmussen