Earth sizzled to a third-straight record hot year in 2016, with scientists mostly blaming man-made global warming with help from a natural El Nino that's now gone.
Two US agencies and international weather groups reported Wednesday that last year was the warmest on record. They measure global temperatures in slightly different ways, and came up with a range of increases, from minuscule to what top American climate scientists described as substantial.
They're "all singing the same song even if they are hitting different notes along the way. The pattern is very clear," said Deke Arndt of the National Oceanic and Atmospheric Administration.
NOAA calculated that the average global temperature for 2016 was 58.69 degrees (14.84 degrees Celsius) - beating the previous year by 0.07 degrees (0.04 Celsius).
NASA's figures , which include more of the Arctic, are higher at 0.22 degrees (0.12 Celsius) warmer than 2015. The Arctic "was enormously warm, like totally off the charts compared to everything else," said Gavin Schmidt, director of NASA's Goddard Institute of Space Studies in New York, where the space agency monitors global temperatures.
The British meteorological office determined that 2016 barely beat 2015 by 0.018 degrees (0.01 Celsius). The World Meteorological Organization and other monitoring groups agreed that 2016 was a record, with the international weather agency chief Petteri Taalas saying "temperatures only tell part of the story" of extreme warming.
The figures are based on ground-level temperatures. Satellite calculations also showed that it was the warmest year, Schmidt said.
"This is clearly a record," he said. "We are now no longer only looking at something that only scientists can see, but is apparent to people in our daily lives."
Temperature records go back to 1880. This is the fifth time in a dozen years that the globe has set a new annual heat record. Records have been set in 2016, 2015, 2014, 2010 and 2005.
Arndt said the 0.07 difference for 2016 is actually one of the largest NOAA has seen between record years. What's more important than any single record is the multi-decade "clear warming trend since the late 20th Century," said Arndt, NOAA's climate monitoring chief.
Schmidt said his calculations show most of the record heat was from heat-trapping gases from the burning of oil, coal and gas. Only about 12 percent was due to El Nino, which is a periodic warming of parts of the Pacific that change weather globally, he said. Arndt put the El Nino factor closer to a quarter or a third.
El Nino disappeared last June. Even without it, Schmidt said this year probably won't break any records although it should be in the top five warmest.
NOAA calculated that last year was the warmest year on record in the oceans, the Arctic and North America. The average amount of ice in the Arctic Ocean reached a record low for 2016, Arndt said.
According to NOAA, 2016 was 1.69 degrees (0.94 degrees Celsius) warmer than the 20th Century average. The first eight months of 2016 all broke heat records. NASA has last year at 1.78 degrees (0.99 degrees Celsius) warmer than their mid-20th Century average and about 2 degrees warmer than the start of the industrial age in the late 19th Century.
"Of course this is climate change, it's overwhelmingly climate change," said Corinne Le Quere, director of England's Tyndall Centre for Climate Change Research, who wasn't part of the NOAA or NASA teams. "Warming (is) nearly everywhere. The Arctic sea ice is collapsing. Spikes in fires from the heat. Heavy rainfall from more water vapor in the air."
The effects are more than just records, but actually hurt people and the environment, said Oklahoma University meteorology professor Jason Furtado. They're "harmful on several levels, including human welfare, ecology, economics, and even geopolitics," he said.
Date created : 2017-01-18