January 2018 Global Temperature Update

January 2018 Global Temperature Update

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Globally January 2018 was the fifth warmest January since reliable measurements began in 1880, 0.78°C warmer than the 1951-1980 mean. January temperature was +1.05°C relative to the 1880-1920 base period that provides our best estimate of pre-industrial global temperature. January temperatures relative to 1951-1980 mean, in order from the warmest, were +1.16°C (2016), +0.97°C (2017), +0.95°C (2007) and +0.81°C (2015).

The strong 2015-2016 El Nino ended about a year and half ago and the tropical Pacific is now in a La Nina phase (temperature anomaly less than -0.5°C; see left side of above figure). Because this year is starting in a deep La Nina, 2018 is likely to decline further relative to the past year, but note that 2017 was still 0.1C above the global warming trend line
(http://www.columbia.edu/~jeh1/mailings/2018/20180118_Temperature2017.pdf). Some ocean models are projecting a possible El Nino in the latter part of 2018, which would tend to reverse the recent short-term cooling trend.

The geographical distributions of January temperature for the past four years are shown below.

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