WEATHER U. S. heat ‘ unprecedented,’ 7,000 records set or tied

WASHINGTON — An “unprecedented” March heat wave in much of the continental United States has set or tied more than 7,000 high temperature records, and signals a warming climate, health and weather experts said on Friday.

While natural climate variability plays a major role, it is the addition of human- spurred climate change that makes this particular hot spell extraordinary, the scientists said in a telephone and web briefing.

“This heat wave is essentially unprecedented,” said Heidi Cullen of the nonprofit science and communication organization Climate Central. “It’s hard to grasp how massive and significant this is.”

Since March 12, more than 7,000 high temperature records have been equaled or exceeded, Cullen said, citing figures from the U. S. National Climatic Data Center

These records include daytime high temperatures and record- high low temperatures overnight, which in some cases are higher than previous record highs for the day, Cullen said.

“When low temperatures are breaking previous record highs, that’s when you see this is incredibly special,” she said.

Cullen noted that this warmth is part of a trend that is pushing the spring season earlier by an average of three days in the contiguous 48 U. S. states.

The date of first leafing — the day when buds burst open — has moved forward from March 20, where it was during the 30- year period from 1951 to 1980, to March 17, where it has been for the period from 1981 to 2010.

— Reuters