The use of indices to identify changes in climatic extremes

Changes in the frequencies of extremes are investigated by a variety of met hods using daily temperature data from the British Isles, and monthly 5 deg rees latitude x 5 degrees longitude grid-box temperatures over the land and marine regions of the world. The 225 year long daily Central England Tempe rature record shows no significant increase in very warm days in recent yea rs but there is a marked decrease in the frequency of very cold days. Thus the rise in temperature in the last two decades is principally associated w ith a reduction in very cold days. Temperatures on days with particular win d circulation or pressure pattern types over the British isles show multide cadal variations. Analyses using monthly gridded temperature data around th e world since 1951 indicate that the recent rise in global surface temperat ures is accompanied both by seductions in the areas affected by extremely c ool temperatures and by increases in the areas with extremely warm temperat ures.