Man has harsher effect on climate than thought

Man's effect on the climate may be worse than feared, according to researchers at Rutherford Appleton Laboratory near Oxford.

They calculated that the Sun has got brighter since observations started in 1868, accounting for early global warming. But later warming cannot be explained by this, they concluded.

"Almost all of the observed global warming up to about 1930 can be ascribed to an increase in the brightness of the Sun, but only about half of it for the period between 1930 and 1970, and less than a third since 1970," said Mike Lockwood. "This confirms that the onset of man-made effects appears to be rather later, but considerably more sudden, than previously thought."