WARMER Arctic summers may be bringing colder winters to Ireland, new research suggests.
Global warming in northern polar regions could be having a surprising knock-on effect further south, scientists believe.
High pressure in the Arctic is thought to push colder air into mid-latitude regions, producing chillier winters.
It could explain a trend of increasingly harsh winters in North America and Europe over the past two decades.
The winter of 2010-2011 will be forever remembered for the coldest December in Ireland since 1962-1963.
Meanwhile on the other side of the Atlantic people braced themselves against abnormally cold conditions for the second year in a row.
The US has experienced the harshest two successive winters for around a quarter of a century.
Cold snaps can occur for a multitude of reasons to do with natural climate variability. But the scientists believe they can see a trend linked to increased autumn snow over northern Europe and Asia.
The findings are published today in the journal Environmental Research Letters.
Lead scientist Dr Judah Cohen, from US-based climate consultants Atmospheric and Environmental Research Inc, said: "In my mind there is no doubt that the globe is getting warmer and this will favour warmer temperatures in all seasons and in all locations; however, I do think that the increasing trend in snow cover has led to regional cooling as discussed in the paper and I see no reason why this won't continue into the near future."
According to the theory, warmer conditions combined with melting sea ice allow the Arctic atmosphere to hold more moisture. This in turn increases the likelihood of precipitation - most probably snow - across more southerly regions.