The effect was first spotted by Gerry Stanhill, an English scientist
working in Israel. Comparing Israeli sunlight records from the 1950s
with current ones, 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," he says.
Intrigued, he searched out
records from all around the world, and found the same story almost
everywhere he looked, with sunlight 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 1-2% globally per decade between
the 1950s and the 1990s.
