The folks at the University of Alabama in Huntsville who are in charge of the satellite temperature dataset that starts in 1979 declared 2016 as the warmest year in that record earlier this month. Now the researchers at the National Oceanic and Atmospheric Administration (NOAA) and NASA have released their data and both also report that 2016 is the hottest year in their land and sea datasets stretching back to the 19th century. From NOAA:
During 2016, the average temperature across global land and ocean surfaces was 1.69°F (0.94°C) above the 20th century average. This was the highest among all 137 years in the 1880–2016 record, surpassing the previous record set last year by 0.07°F (0.04°C). The first eight months of the year had record high temperatures for their respective months. Since the start of the 21st century, the annual global temperature record has been broken five times (2005, 2010, 2014, 2015, and 2016). The record warmth in 2016 was broadly spread around the world.
During 2016, the globally-averaged land surface temperature was 2.57°F (1.43°C) above the 20th century average. This was the highest among all years in the 1880–2016 record, surpassing the previous record of 2015 by 0.18°F (0.10°C). …
During 2016, the globally-averaged sea surface temperature was 1.35°F (0.75°C) above the 20th century average. This was the highest among all years in the 1880–2016 record, surpassing the previous record of last year by 0.02°F (0.01°C).
Earth's 2016 surface temperatures were the warmest since modern recordkeeping began in 1880, according to independent analyses by NASA and the National Oceanic and Atmospheric Administration (NOAA).
Globally-averaged temperatures in 2016 were 1.78 degrees Fahrenheit (0.99 degrees Celsius) warmer than the mid-20th century mean. This makes 2016 the third year in a row to set a new record for global average surface temperatures.
The 2016 temperatures continue a long-term warming trend, according to analyses by scientists at NASA's Goddard Institute for Space Studies (GISS) in New York. NOAA scientists concur with the finding that 2016 was the warmest year on record based on separate, independent analyses of the data.
Because weather station locations and measurement practices change over time, there are uncertainties in the interpretation of specific year-to-year global mean temperature differences. However, even taking this into account, NASA estimates 2016 was the warmest year with greater than 95 percent certainty. …
Not only was 2016 the warmest year on record, but eight of the 12 months that make up the year — from January through September, with the exception of June — were the warmest on record for those respective months. October, November, and December of 2016 were the second warmest of those months on record — in all three cases, behind records set in 2015.
According to their data, the NASA researchers report most of the warming occurred in the past 35 years, with 16 of the 17 warmest years on record occurring since 2001. While now all three U.S. temperature records show this past year as the hottest, researchers disagree on its significance. For example, in a statement NOAA researcher Gavin Schmidt observes: "2016 is remarkably the third record year in a row in this series. We don't expect record years every year, but the ongoing long-term warming trend is clear." On the other hand, in a press release satellite temperature UAH researcher John Christy asserted, "The question is, does 2016's record warmth mean anything scientifically? I suppose the answer is, not really. Both 1998 and 2016 are anomalies, outliers, and in both cases we have an easily identifiable cause for that anomaly: A powerful El Niño Pacific Ocean warming event. While El Niños are natural climatic events, they also are transient. In the study of climate, we are more concerned with accurately identifying long-term temperature trends than we are with short-term spikes and dips, especially when those spikes and dips have easily identified natural causes."
Interestingly, the UAH folks report a global climate trend since Nov. 16, 1978 of +0.12 C per decade. The NOAA researchers find that the globe has warmed at a rate of +0.17 C per decade over the past 45 years.