In recent decades there has been increased variability in yearly temperature records for large parts of Europe and North America, a study by scientists from a number of UK institutions has shown.

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The scientists, from the Centre for Ecology & Hydrology, University of East Anglia and University of Exeter also found that regions of high variability have moved markedly over the last five decades. As the climate has changed, greater temperature variability has affected more densely populated areas of the two continents studied.

The study's lead author, Dr Chris Huntingford from the Centre for Ecology & Hydrology said, "Fluctuations in annual average temperatures have shown very substantial geographical alteration in recent decades. However, to our surprise, when considered across the globe, total variability has been relatively stable." He continued, "The movement of raised temperature variability to regions of high population may have contributed to the general perception that climate is becoming more volatile."

Co-author Professor Phil Jones, from the University of East Anglia said, "We used globally-complete surface temperature data that has been constructed by merging observations and weather forecasts, and verified our findings against station temperature records."

The analysis looked at year-to-year variability in temperature at different geographical locations; the researchers said the variability they studied is occurring around general global warming trends. They disregarded the trends associated with global warming and analysed the remaining temperature "anomalies" for changes over time and space.

Temperature fluctuations to decrease as global warming takes effect

The study also looked at future projections by 17 climate model simulations.  Almost all predict that overall temperature fluctuations will actually decrease towards the end of this century, as greenhouse gas concentrations in the atmosphere increase.

Co-author Professor Peter Cox, from the University of Exeter said, "Evidence [suggests] that decreasing global temperature variability will be a consequence of major sea-ice loss in a warmer world."

Dr Huntingford added, "Our findings contradict the sometimes stated view that a warming world will automatically be one of more overall climatic variation."