Though there are still two weeks of the year left, temperatures have already been so high in so many countries that 2014 is expected to be the hottest on record in Europe and globally.
Climate scientists have said for decades the carbon dioxide emissions produced by burning coal, oil and gas are warming global temperatures.
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But until recently they have been reluctant to blame global warming for specific weather extremes.
This is starting to change as researchers deploy increasingly sophisticated computer models to compare the chances of such anomalies occurring with and without the influence of humans on the climate.
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Environmental lawyers are already watching developments in this emerging field of so-called climate attribution science closely, to see if it opens the way for legal action against large fossil fuel companies.
"In the early 1900s, before global warming played a significant role in our climate, the chances of getting a year as warm as 2014 were less than 1-in-10,000. In fact, the number is so low that we could not compute it with confidence," said Geert Jan van Oldenborgh, a climate scientist at KNMI, the Royal Netherlands Meteorological Institute.
The institute calculated global warming made this year's high temperatures in Europe at least 80 times more likely.
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For many individual countries, the probability increased by a factor of at least 30, including the UK and several central European nations.
At least 19 European countries are likely to see their hottest year on record this year, including the UK, Germany and France.
Initial estimates by KNMI show the average temperature in Europe this year will be 10.5ºC. This is 0.3ºC above the previous record set in 2007.
That means it is likely to be warmer than any of the last 500 years, the scientists say, based on analysis of early instrumental records, and proxies for such data like tree rings.
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Nine of the 10 hottest years recorded worldwide have occurred since 2000 and there has not been an annual global cold record set since 1911, according to the National Climatic Data Center in the US.
The trend is similar in Europe, where scientists say there has not been an annual cold record set across the continent since 1956.
Three teams of researchers from Oxford, The Netherlands and two Australian universities worked independently using different techniques to produce the latest results for Europe.