Climate changes

Last Updated: Saturday 04 July 2015

According to scientists at the Rutherford Appleton Laboratory (RAL), near Oxford, UK, the Sun's field has more than doubled in the last 100 years, while its total magnetic flux has risen by a factor of 1.4 since 1964. The Sun's brightness has increased by one per cent during the last century. The increase may be related to chaotic changes in the "dynamo" that generates the solar magnetic field. Solar magnetism is closely related to sunspot activity and luminosity, both of which affect the Earth's climate. "The results indicate that almost all of the observed global warming up to 1930 can be ascribed to an increase in the brightness of the Sun, but only about half of it for the period 1930-1970 and less than a third since 1970," said RAL's professor Mike Lockwood, adding, "This confirms that the onset of human-made effects appear to be rather later but considerably more sudden than previously thought" ( Spectrum , No 272).

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