I live in Maine. Thank God we haven’t gotten as much of the “polar vortex” as other states … but we’ve had our share. It’s cold.
But overall, temperatures in Maine haven’t been going down. They’ve been going up. Here’s temperature anomaly for Maine for each month since January 1895, showing how much colder or hotter than average each month was:
That red line is a “trend” line. It’s just an estimate, mind you, but it’s based on math, and it passes all the mathematical tests. It says: overall, Maine has warmed since 1895 by about 3.2°F (1.8°C).
That’s global warming come to Maine, which makes it local warming. It’s called “warming” because it’s a trend in temperature which is going up.
Pay attention, dumbass! Trend. Temperature. Up. That’s global warming. It’s not the fluctuations, it’s not the weather, it’s the overall trend in temperature going up. Not a “pretend” trend, like “boy was it cold yesterday!” A real trend, that doesn’t just use math, it passes the mathematical tests.
Not all seasons have shown the same warming. Here in Maine, when we look at the temperatures for only the winter months (that’s December+January+February when it comes to climate) we see this:
Winter temperatures have risen (on average) fully 5°F (2.8°C), faster than the yearly averages. Again, that’s a trend in temperature going up.
Then there’s this thing called climate change.
I notice that in Maine, in spite of the warming trend in winter temperature, some of the coldest winter months on record are in the later part of the record. Coldest of all was December 1989 at nearly 14°F colder than average, and that’s not a single December day, it’s the average for the entire month! That’s one wild and crazy cold month. Even as recently as 2015, we had a February nearly 10°F below average (again, not for just a day but averaged over the whole month). Is that crazy or what? But the hottest winter months have also been recent. What’s going on?
The trend represents how the average is changing. But it doesn’t tell us anything about the fluctuations. Are they getting bigger, or smaller, or staying about the same? Is there any change in the way temperature fluctuates, independent of whatever changes its average might show? If so, it won’t be global warming (or any warming for that matter), it will be climate change.
You see, climate is not the same as weather, and climate change is not the same as global warming. And global warming isn’t about the fluctuations or the weather, it’s about the trend.
That overall increase in temperature (be it global, or just winter in Maine) — that’s warming. Any recent tendency to fluctuate more than it used to, to swing wildly from hottest to coldest — that’s climate change. Man-made climate change.
Do you get it? Or do you need my foot in your ass?
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Good summary about what’s been happening in Maine as far as temperature is concerned. The TREND of temperatures have definitely been going up faster in winter than summer though the wild swings are also becoming more frequent (a function of a weaker polar jet which has become loopier and lazier with big swings as sluggish long waves now move through the flow more often). If you have included other things besides the temperature trends, you could have included much more cloudy days and nights over the last 40 years making it much harder to see the Milky Way which hardly ever is visible any more. I could go on and on with all kinds of subtle and not so subtle changes that have occurred with definitely changing Maine climate!!
If you’re speaking to Trump, he definitely needs somebody’s foot in his ass. Maybe Robert Mueller’s.
You kind of teased the question, but didn’t really address it. But now I’m curious: is there statistical evidence for increasing variability in temperature, in Maine or anywhere else for that matter?
Doc — As a partial response to your question regarding variability, some years ago I did an analysis of daily high and low temperatures for Minneapolis, MN for the period 1950-2012 (first mentioned by me as a comment here: https://tamino.wordpress.com/2015/07/07/actually/). I determined monthly mean and standard deviations of temperature separately for the daily highs and lows, and looked at them vs. year for the indicated period. Briefly, the trends varied by month. Little change was seen for a subset of the data consisting of the years 1950-1978, but significant increases were seen for the overall period (1950-2012) and 1978-2012, with the most significant increases seen in the daily lows rather than in the daily highs.
However, when I looked at plots (and linear regressions) of the monthly temperature standard deviations (as a measure of variability) vs. year, I saw no significant changes for either the daily highs or lows with the possible exception of January high temperatures where there was a weak but statistically significant trend toward reduced temperature variability (reduced standard deviation). For other months, the trend in S.D. was actually down but not significantly so.
Obviously, this analysis applies only to a particular time period in a particular place.
Thanks. Interesting, but I guess inconclusive.
In light of the latest laments over the polar vortex and extreme cold weather in the midwest (moving east) I decided to take a look at the history of cold in the Minneapolis area (where I grew up in the 1950s and 60s). I counted the total number of days per year where the low temperature was less than 0 F, less than -10, and less than -20 for all years from 1950 through 2017. There is a lot of year-to-year variability, but the trend toward milder winters seems clear. A bar graph shows the result, but linear regression of number of days reaching each temperature threshold per year (perhaps not the best statistical technique to apply) show a significant decline at each of the temperature levels:
# of Days R^2 P
<0 0.26 4.05e-5
<-10 0.32 2.64e-6
<-20 0.22 0.0002
Between 1962 and about 1996, there were 6 years where the number of days below -20 was 7-8 per winter, and 16 where there were at least 4 such days per winter. Since then, no more than 2 days per winter, and only 8 total days where the temperature was lower than -20 F from 1997 through 2017. I don't have the data for 2018 at the moment, but it looks like there will be at least 2 in 2019.
Incidentally, the record low temperature recorded in Minnesota was -60 F on Feb. 2, 1996.
Cliff Mass has a good post on the subject (agrees with Robert):
What data set for temperature were you using?
There is a term whose use is growing as part of Extinction Rebellion (see the Facebook groups Extinction Rebellion and Extinction Rebellion Elders). It was coined by climate change activist Dahr Jamail dahrjamail.net and it more accurately replaces both global warming and climate change. You may wish to start using this term too. It is “anthropogenic climate disruption”.
Global heating and climate destabilization
The addition of “Anthropogenic” in any term apportions blame to the human causes of this catastrophe.
Yes, but it’s a bit Latinate for general consumption. Where indicated–or at least, where I think it’s indicated–I’ll substitute “human-induced.” It’s still a bit clunky, unfortunately, but less pretentious-sounding, and perhaps actually clearer for some.