Its mid-January, which means the jokes about New Years resolutions are hopefully fading out along with your seasonal depression. Oh, and NOAAs and NASAs final 2019 global temperature analyses have dropped. (No need to get the party hats and noisemakers back out.)
Lets start with the numbers. Last year comes in as the second warmest on record in almost every dataset. The UK Met Office dataset has it in third place, as does one satellite dataset (though it is a bit out of step with other satellite records). Satellite datasets measure temperatures higher in the atmosphere rather than surface temperatures, so small differences are not uncommon. Surface temperature datasets generally go back to the late 1800s, while satellite datasets begin in 1979.
The biggest piece of context you need to understand these annual updates is the El Niño Southern Oscillation—a see-saw of Pacific Ocean temperatures that pushes the global average a little above or below the long-term trend each year. In an El Niño pattern, warm water from the western equatorial Pacific drifts toward South America. In a La Niña pattern, strong winds hold that warm water back, pulling up deep, cold water along South America. Years in which El Niño dominates tend to have a higher global average surface temperature, while La Niña years are a little cooler.
This pattern was actually pretty neutral in 2019, starting slightly to the La Niña side of neutral and ending on the El Niño side, but without ever being strong enough to be categorized as either. That means 2019 got only a small upward boost. And still, it ranks as the second warmest year on record, behind only 2016, which saw a strong El Niño.
This comes as no surprise to climate scientists. As we noted last year, the UK Met Office, the Berkeley Earth group, and NASAs Gavin Schmidt all predicted that 2019 would most likely end up 2nd based on the outlook for a neutral El Niño Southern Oscillation.
One can contrast that with those who reject the science of human-caused climate change and have declared for decades now that the warming trend would halt and reverse. Last year provides yet another data point that fails to match their hypothesis.
For the United States, 2019 was only the 34th warmest year on record. While portions of the Southeast and Mid-Atlantic had a very warm year, the Northern Plains were quite cool. Alaska had its warmest year on record, though, at a remarkable 6.2°F above the 1925-2000 average.
On the precipitation side, it was the second wettest year on record for the US. That included a general improvement in drought conditions, although the Four Corners region and southernmost Alaska were quite dry.
The US experienced 14 weather-related disasters exceeding a billion dollars in damage (adjusted for inflation), for a total of $45 billion in direct losses. That ranks fourth since 1980 and ties 2018.