The Raw Data
Unspun and unbiased. These are the facts.
The U.S. National Aeronautics and Space Administration (NASA) reported on Thursday that 2017 was the second hottest year since 1880, the earliest year NASA uses to compare global temperature records. The National Oceanographic and Atmospheric Administration (NOAA), using different methodologies, determined 2017 was the third hottest year, after 2016 and 2015. NASA said that the temperature has risen about 2 degree Fahrenheit (1.1 degree Celsius) over the past century.
NASA estimated 2017 would have been the hottest year on record were it not for the El Niño warming event that occurred during the majority of 2015 and the first third of 2016, and the La Niña cooling event starting in the second half of 2017. El Niño and La Niña periods are part of the natural variations in the surface temperature of the Pacific Ocean; El Niño times coincide with an increase in temperatures, and La Niña a decrease in temperatures.
Both NASA’s and NOAA’s analyses show that the five warmest years on record have occurred since 2010. Petteri Taalas, Secretary General of the U.N.’s World Meteorological Organizations, said that 17 of the 18 hottest years on record have come this century.
NASA attributed the increase in average temperature since the end of the 1800s as “largely” due to increased carbon dioxide and “other human-made emissions into the atmosphere.”
The Paris Agreement set a goal of limiting average temperatures to no more than a 2.7 degree Fahrenheit (1.5 degree Celsius) increase since “pre-industrial” levels.
NASA says its analysis uses “surface temperature measurements” from 6,300 locations around the world on land and sea. NASA notes that temperature recording locations and measurement techniques have changed with time. This variation introduces some uncertainty, and can be partially accounted for in models. Given that, NASA estimates accuracy to within 0.1 degree Fahrenheit with a 95 percent certainty level. NOAA’s data collection methods differ, which accounts for the discrepancies between its findings and NASA’s findings for the year 2017.