* More than 60 killed in Portugal forest fires
* Global warming raised risks of extreme heat
OSLO, June 29 (Reuters) - Man-made climate change contributed to scorching heat across Western Europe this month, when Portugal suffered deadly forest fires and many nations sweltered under record-breaking temperatures, scientists said on Thursday.
Monthly temperatures for June are set to be about 3 degrees Celsius (4.8 Fahrenheit) above long-term averages for Western Europe, the World Weather Attribution group of scientists said in a report.
"We found clear and strong links between this month's record warmth and human-caused climate change," said Geert Jan van Oldenborgh, senior researcher at the Royal Netherlands Meteorological Institute, one of the authors.
Climate change, stoked by man-made use of fossil fuels, had made the intensity and frequency of such heat at least four times more likely in France, Switzerland, the Netherlands and central England and made it 10 times as likely in Portugal and Spain, the study found, based on historical trends.
The scientists said the heat was vanishingly unlikely to be a freak natural event, and could not be explained by shifts in the sun's output or by other natural factors such as low amounts of sun-dimming volcanic dust in the atmosphere.
That meant that a build-up of man-made greenhouse gas emissions, mainly from burning fossil fuels, had raised the risks.
"By the end of the century, these high temperatures will become the norm in Western Europe," they added.
"Heat can be deadly — especially for the very young and the elderly," said Friederike Otto of Oxford University who was one of the authors. "It is critical that cities work with scientists and public health experts to develop heat action plans."
Forest fires in Portugal killed more than 60 people and more than 2,000 people were evacuated in Spain to escape wildfires.
Heat wave plans were triggered in France, Switzerland and the Netherlands in June. Much of France had the hottest June night on record on June 21 and England had its hottest June day since a summer heatwave in 1976. (Reporting By Alister Doyle)
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