As we emerge from a bitter cold-snap that lasted about a week here in Bend, Oregon (my home town), the thought crossed my mind that we need more global warming–literally. You see, I don’t care much for cold weather anymore. And by cold, I’m talking single-digit cold. I know, I know… the hardy folks who live farther north may consider me a sissy, and that’s okay. I’m at that point in my life where my desire to be comfortable takes precedence over third-party opinions of my manliness.
I’m not ready to say that our start of winter is harsher than normal—after all, when we talk about the weather what is “normal”? I certainly recall some winters in Bend, most especially back in the late 1980s, when we had prolonged stretches of very cold weather with night-time low temperatures in the single digits and even below zero. That’s when I learned not to set the parking brake on my Toyota pickup for fear that the brake may freeze and lock the wheels, and I’d not be able to release it. I also learned how to keep the pipes in my house from freezing (tip: close the foundation vents).
All this reminiscing and thinking got me wondering, has the pattern of summer and winter temperatures in Bend really changed? To listen to the news media, one is left with the indisputable conclusion that Earth is undergoing a rapid increase in global temperature. Surely, that must be reflected in my home town—so why is it so damn cold?
Since I’m a man of science, I did what all scientists do when they can’t answer a question—I got data. Not just a little data, but a lot. I found historical records of the average January temperature and average July temperature going back to 1902, input that data into a spreadsheet, and then plotted the data. Once done, I wanted to look for trends—specifically, is it getting warmer or colder since 1902. The plot is shown here so you can see what I found. Consistent with my memory, the average temperatures vary considerably from year to year. Now that I had all this data, I wanted to know, is global warming really causing it to be warmer in Bend?
To answer this question, I first fit a straight line to the data. You’ll see the nearly horizontal black line going through the data in the graph—not a very good fit. By this I mean that most of the data is well above or well below the straight black line. Not surprising. So I decided to get more sophisticated and I used a polynomial expression. Big words, and more complicated math compared to a linear expression, but super easy to do in an Excel spreadsheet. Just a few mouse clicks, and this nice wavy (green) line was overlaid on the data. Bingo! I was making progress; this is a much better fit to the data as you can see.
Now, here’s the deal. When the data fits a wavy line, like this 110 years of temperature data, and you look to extrapolate into the near future, whether the temperature is projected to increase or decrease depends on where you are on that wavy line. If we are on an upslope, then temperature is expected to increase in forthcoming years. But if we are on a down slope, just the opposite is expected. And based on my admittedly simplistic analysis, it appears Bend has just reached the peak of the wavy line for both winter and summer seasons. This means that the past 30 to 40 years of gradual temperature increase in Bend is likely to revert and follow a trend of decreasing temperature for several decades.
Rats! Colder winters and cooler summers—not what I wanted from global warming. Time to seriously consider moving south to a location where palm trees are native, the sand and water are warm, and only the beer is ice cold.
Oh, just in case you are interested in temperature patterns for other parts of the U.S., here are the results of similar data analyses I conducted for Brockton, MA (a suburb of Boston) and for Dallas, TX.