EXETER (Reuters) - Global warming is forcing weather scientists at the Met Office to change the way they compare seasonal temperatures, they said on Wednesday. The national weather forecaster compares average temperatures to the long-term average for 1971-2000, but forecasters say this benchmark is increasingly irrelevant and is being supplanted by new ways of calculating the average.
"Climate references are changing, so there is a need to revolutionise the way we do this," climate scientist Richard Graham said on the sidelines of a Met Office conference. The last nine summers have been hotter than the 1971-2000 average of 14.1 degrees Celsius, and forecasters expect this summer will be no exception.
For the first time, weather scientists are generating a new 30-year average, calculated using 15 years of historic data and 15 years of predicted future temperatures, Graham said. Future temperatures are calculated using a forecasting system introduced this year and give a far more accurate picture of how individual summers compare over a long-term period.
"This new method is great for business uses; it could be of use to the public forecast as well," Graham said.
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