WASHINGTON—Last year wasn’t just the Earth’s hottest year on record — it left a century of high temperature marks in the dust.
The National Oceanic Atmospheric Administration and NASA announced Wednesday that 2015 was by far the hottest year in 136 years of record keeping. For the most part, scientists at the agencies and elsewhere blamed global warming and El Nino.
NOAA said 2015’s temperature was 58.62 degrees Fahrenheit (14.79 degrees Celsius), passing 2014 by a record margin of 0.29 degrees. That’s 1.62 degrees above the 20th-century average. NASA, which measures differently, said 2015 was 0.23 degrees warmer than the record set in 2014 and 1.6 degrees above 20th century average.
Because of the wide margin over 2014, NASA calculated that 2015 was a record with 94 percent certainty, more than double the certainty it had last year when announcing 2014 as a record. NOAA put the number at above 99 percent — or “virtually certain,” said Tom Karl, director of NOAA’s National Centers for Environmental Information.
For the first time Earth is 1 degree Celsius (1.8 degrees Fahrenheit) warmer than it was in pre-industrial times, NOAA and NASA said. That’s a key milestone because world leaders have set a threshold of trying to avoid warming of 1.5 or degrees Celsius above pre-industrial times.
