Thoughts on the ocean, the environment, the universe and everything from nearly a mile high.

Panorama of The Grand Tetons From the top of Table Mountain, Wyoming © Alan Holyoak, 2011

Tuesday, April 10, 2012

March 2012: The warmest on record

Is it global warming?  Is it an isolated temperature spike?  Whatever it was, it was amazing!  March 2012 was the warmest March in the lower 48 states since we started collecting temperature data - 118 years ago.

Click on the link below to watch a report on this story from

The National Oceanic and Atmospheric Administration (NOAA) confirmed the new monthly record high.  How warm was it?  March 2012's average temperature was over 8oF warmer than the historical average for March. That's huge!

How widespread was the warming?  The number in each state on the map below shows how March 2012's average temperature ranked among the 118 monthly averages we've got between 1894 and now.  A "118" means it was the warmest March ever...a "117" means it was the the second warmest ever, and so on.  Twenty-five states had all time high average monthly temperatures.  Washington, Oregon, and California were the only states NOT at least in the upper half of their historical averages.  Wow!
(Image credit: NOAA)

If that's not enough to blow your mind, over 15,000, yes, that's fifteen THOUSAND record high temperatures were tied or broken last month!  Double wow!

(Image credit: NOAA)

Each of the red dots (15,292 of them) show the 7,775 daytime highs and the 7,517 nighttime high temperatures that tied or exceeded previous records!  According to NOAA, 21 of the nighttime high temperatures exceeded the former daytime high temperatures on those dates!  Yow!

The March average annual temperatures for the past 118 years are shown below.  There is a lot of variability (also called noise) in the data.  FYI - The flat black line is the average of all data in the set, so about half of the observations will be below the line, and half will be above the line.  The blue dots and lines represent individual average March temperatures.  The green line represents a rolling average of the data (well, sort of, it's a filter that smooths the data so we can see longer-term trends), and the red line shows the overall trend in the entire data set.

If you look at the green rolling average again, you'll see that between the late 1800s and the 1970s there was a lot of variability, but if anything a very slight cooling trend.  Then between 1970 and today you can see a more or less steady rise in the average temperatures.

(Image credit: NOAA)

All right.  The elephant in the room, i.e., the big question is this, "Was the observed extreme high average temperature in March 2012 caused by global warming?"  

That's a tough call.  It is difficult statistically to connect an isolated weather event, like a high monthly average temperature, with global warming. But, given the warming trend that started in the 1970s and that we see continuing today, it is fair to say that as the planet continues to warm it is more likely that these types of warming events will take place.  That's about as far as we can go in answering that question.

It'll be interesting to see what April brings.  As for where I live, the forecast high temperature for today is 74oF, 18oF higher than the monthly average for April.  

Happy spring everyone!

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