Bank Holiday sunseekers this weekend may find it harder to get a tan. And cinema-goers emerging from the global warming blockbuster, The Day After Tomorrow, will have something new to worry about. For scientists have discovered the awful truth; we are all dimmed.
New research shows that much less sunlight is reaching the earth than 50 years ago. "Global dimming", as it has inevitably become called, has been suspected for nearly 20 years, since a Swiss geography researcher, routinely checking sunshine levels across Europe in 1985, found that they had dropped, even on the brightest days. Studies all around the world found similar results, showing drops in sunlight ranging from 2 to 37 per cent since the 1950s.
The research, published in Science, is the first to prove that the dimming is a global phenomenon. Scientists at the New Jersey and California Institutes of Technology remembered how Leonardo da Vinci had worked out that the dark side of the moon was illuminated by sunlight reflected from the Earth. By measuring this "Earthshine" they worked out that the world is about 10 per cent darker than half a century ago.
Scientists are divided over whether global dimming is a natural phenomenon or caused by pollution, such as soot particles emitted from car exhausts, and global warming, which evaporates more water from the Earth, causing more clouds. Professor Philip R Goode, who led the study, told The Independent on Sunday that the way the dimming has varied suggests that it may be a natural phenomenon.
Whatever the cause, there could be massive effects on farming and on attempts to capture solar energy as the earth "dims down".
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