The Influence of Solar Activity on Climate Change - the Evidence from Northern Ireland

C.J. Butler

To be published in 'Global Warming' - ' The report of the European Science and Environment Forum'. ESEF 1996

It has been shown by Friis-Christensen and Lassen (1991) that there is a close correspondence in the behaviour of the mean northern hemisphere air temperature and the length of the sunspot cycle, over the period 1861-1990. This result would appear to be of considerable importance for studies of both past and future climate and suggests that, as the solar dynamo speeds up, it causes by some process as yet unknown, an increase in the temperature of the Earth's troposphere. In this paper we extend the comparison between sunspot cycle length and temperature back to the late 18th century using data accumulated at Armagh Observatory since 1795. Our data support the contention that solar variability has been a major cause of temperature changes over the past two centuries.