Monday, November 14, 2016

Climate of 2016 to date

No, I'm not talking about the recently concluded US election that saw a scientific illiterate ascend to the presidency. Given the lack of details about Donald Trump's intended policies, it's impossible to say what, exactly, his election means for science in the US although I have doubts that it means anything good given his stated antithesis toward science, particularly climate science. I will instead focus on some significant events that have been eclipsed in the media frenzy around the presidential campaign.

First up, global temperature. Has it been hot enough for you? Here are January through September temperatures for every year in the GISS record.
 So far, 2016 has obliterated the previous record for January - September global temperature anomaly set in 2015, 1.03ºC to 0.80ºC. Not only is the average for the first nine months hotter but eight of those months are the hottest respective months on record, with only June 2016 (in third place) the lone non-record-setter. That streak of hot months won't continue, however. The last quarter of 2015 was extremely hot thanks to El Niño. We're now in neutral conditions, so the last quarter of 2016 is unlikely to be hotter than the last quarter of 2015.

Now the president-elect of the US may not believe that the world is getting hotter but science is true regardless of personal opinion.

What are the chances that 2015 will retain its crown as hottest year in the GISS record? Short answer: Slim to none. The annual temperature anomaly in 2015 was 0.87ºC above the baseline. So far, 2016 has an eye-popping anomaly of 1.03ºC. For 2016 to miss being the hottest year on record, the last quarter of the year would have to have an average temperature anomaly of 0.39ºC.

Simply put, that's not going to happen. The probability of the three month average dropping that low in 2016 is 0.26%. There's a chance that 2015 will retain its crown, yes, but there's no way I'd bet against the 99.74% chance 2016 takes the crown away.

Also obscured by the hyperventilation over the US presidential election? The monthly atmospheric carbon dioxide crossed the 400 ppmv barrier in November 2015—and has not dropped back below that level as of September 2016. It's unlikely to do so since September usually sees the lowest CO2 levels of the year. Welcome to a world where CO2 is permanently above 400 ppmv, a world last seen in the Pliocene. Oh, in case you're wondering, the 12-month centered moving average has been above 400 ppmv since March 2015, now standing at 403.3 ppmv.
Finally, Arctic sea ice slipped to its third-lowest September extent on record, with a monthly average of just 4.51 million square kilometers of permanent sea ice in the Arctic Ocean this past September. The only years in which there was less permanent sea ice? The record lows of 2012 and 2007.
In short, global warming has continued in 2016 thanks to the continuous rise in CO2. As it has for the last century, as it will for the foreseeable future regardless of political opinion.

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