July 2016 was world's hottest month since records began, says Nasa

Nasa’s results, which combine sea-surface temperature and air temperature on land, show July was 10th month in a row to break monthly temperature record
Michael Slezak The Guardian 16 Aug 16;

Last month was the hottest month in recorded history, beating the record set just 12 months before and continuing the long string of monthly records, according to the latest Nasa data.

The past nine months have set temperature records for their respective months and the trend continued this month to make 10 in a row, according to Nasa. July broke the absolute record for hottest month since records began in 1880.

Similar data from the US National Oceanographic and Atmospheric Administration (Noaa) said the past 14 months have broken the temperature record for each month, but it hasn’t released its figures for July yet.

The new results were published on the Nasa database and tweeted by climatologist Gavin Schmidt, director of the Nasa Goddard Institute for Space Studies.

Nasa’s results, which combine sea surface temperature and air temperature on land, showed July 2016 was 0.84C hotter than the 1951 to 1980 average for July, and 0.11C hotter than the previous record set in July 2015.

As the string of hottest months continues, 2016 is “virtually certain” to be the hottest year on record, said David Karoly, a climate scientist from the University of Melbourne.

That string was caused by a combination of global warming and El Niño, which spreads warm water across the Pacific, giving a boost to global temperatures.

Karoly pointed out that Nasa’s baseline temperatures, which new measurements are compared against, already included about 0.5C of warming in global temperatures. That meant July was about 1.3C warmer than the pre-industrial average.

Karoly said about 0.2C of that anomaly was likely due to the El Niño, leaving about 1.1C mostly due to human-induced climate change.

The El Niño itself has dissipated, but the effects on global air temperatures lag for between three and six months, Karoly said. As the El Niño declines, the size of the monthly anomalies has been decreasing, with February 2016 showing the biggest anomaly since records began, being an extraordinary 1.32C hotter than the average February between 1951 and 1980.

Eventually, the monthly temperature records will stop, Karoly said. “We are still seeing the tail end of the El Niño warming in global temperatures,” he said. “We’re not going to set any records later this year.”