This December was crazy hot. Most readers are aware of how unusually warm it was last month in the eastern U.S., but it was just as crazy hot — maybe more so — in England.
As a new year arrives, organizations which track climate release complete data for the preceding year. One of the first to do so, and the first I acquired, was daily Central England Temperature. It reports daily mean temperature since 1772, nearly 250 years’ worth.
That enables me to compute temperature anomaly (the difference between a given day’s temperature, and what’s typical for that day of the year), and to calculate monthly averages of same. This tells us how much hotter or colder than average was each month. I won’t keep you in suspense, here’s the December monthly temperature anomaly for all 244 years of record:
The final value, for December 2015, is circled in red at the right. It’s the hottest December on record. By a long shot. Here’s a histogram of December temperature anomalies:
The loner on the right, circled in red, is for a single value: December 2015. No other December got as hot as 4 deg.C anomaly, but this one exceeded 5.
Prior to 2015, the hottest December in the CET record was for 1934 — but it edged out 2nd-place 1974 by the narrowest of margins, a mere 0.003 deg.C. This year took 1st place, beating now-2nd-place 1934 by a whopping 1.58 deg.C.
It wasn’t just the hottest December on record, it’s the hottest monthly anomaly on record. By a long shot.
The final value, circled in red on the right, is for December 2015. It beat the now-2nd-place record by a whopping 1.38 deg.C. Here’s a histogram of all monthly temperature anomalies:
The circle on the right is for a single value: December 2015. Since it’s only 1 out of 2928 months on record, the bar representing it is too short to see. Only one other month exceeded 4 deg.C anomaly, and that by a little; this one exceeded 5, by a substantial margin.
I’m sure the deniers want to talk about how there are cold months too — even recently. But none have been as cold as this one was hot. Still, there is a good point to make: that we should put more emphasis on the trend than on the fluctuations. Lord knows I’ve emphasized that point myself often enough.
Climate is generally defined over 30-year periods. Maybe it’s a good idea to compute 30-year moving averages, to see what the recent trend value looks like. Even the most recent value will be only slightly influenced by this December’s record heat, it’ll be dominated by the other 359 months making up a 30-year period. Here ya go:
We haven’t just seen an astounding record-breaking December temperature in Central England. We’ve also seen a shocking upward trend.
Deniers love to find a cold month — or day — or snowball, if you’re a politician — and bleat about how it contradicts global warming. They love to complain when a super-hot month draws attention to global warming. They avoid the fact that the hots are hotter but the colds not quite so cold. And if they talk about trend at all, they’ll pick some all-too-brief span of time, and cherry-pick the start time, just so they can use the word “trend” without embarrassing their denial of man-made climate change. But when you look at trends which are long enough to tell the real story, you usually get a picture like the one above.
The plotted time is the mid-point of each 30-year period; the latest value represents 2001, covering the time from January 1986 through December 2015. If we want an estimate which goes up to the present, we can use a good smoothing method. I applied a modified lowess smooth on a 30-year time scale, giving this (plotted in red, I’ve superimposed it on the 30-year moving averages which are in black):
Whether you look at the most recent month, or the recent trend, it’s a bad time for global warming deniers in England.
Come to think of it, it’s a bad time for global warming deniers everywhere.
But, they haven’t had their last hurrah yet. Fluctuations will keep fluctuating, sometimes up (like now) and sometimes down. When the fluctuation goes down, they’ll have more to bleat about. And bleat they will. They’ll even sucker some people — after all, you really can fool some of the people all of the time.
But people are starting to notice. Even in the U.S.A. People are starting to “get it” — and even when the fluctuation goes down, more of them will remember rather than forget. They’ll realize, even when the cold comes, that it’s not quite as cold, but the hots are hotter. Some may even remember that it’s the trend that counts, and that ain’t goin’ away. It’s goin’ up.
After all — you can’t fool all of the people all of the time.