Just out of a period here in upstate New York, where temperatures never exceeded 40 degrees for nearly three solid months, when I saw this headline on NBC News, I thought they might announce something really inspiring. “Summers could last half the year at the end of this century. But if you live in the Northeast, it still looks like this could turn out to be good business.
Summers in the northern hemisphere could last nearly six months in 2100 if global warming remains uncontrolled, according to a recent study that examined how climate change affects the pattern and duration of Earth’s seasons.
The study, published last month in the journal Geophysical Research Letters, found that climate change makes summers hotter and longer, while reducing the other three seasons. Scientists say the irregularities could have a number of serious implications that would affect human health and agriculture in the environment.
“This is the biological clock of all living things,” said the study’s lead author, Yuping Guan, a physical oceanographer at the State Tropical Oceanography Laboratory of the Chinese Academy of Sciences.
Guan and colleagues combed daily climate data from 1952 to 2011 to pinpoint the start and end of each season in the northern hemisphere. They found that during the nearly 60 years, summers were turning into an average of 78 to 95 more days.
I guess it’s best to take a look at the data they use and find out if there’s anything in that theory. The Guan team claims to have compiled all the daily climate data from 1952 to 2011. Using this data, they worked to “identify the beginning and end of each season in the northern hemisphere“Based on these figures, they concluded that during this 59-year period,”summers were turning into an average of 78 to 95 more days“.
Wow. It is certainly a shocking figure. But there is a major problem with it. I’m not sure if this was just a typo in the NBC article or if someone lost the calculator, but that figure would indicate that ten years ago summer was already up to three months longer than the first fifties. As if that number doesn’t sound right, the report becomes more specific and says the other three seasons, on average, contract with the following amounts.
- Winters were shortened from 76 to 73 days
- The springs were shortened from 124 days to 115 days
- Autumns were shortened from 87 days to 82 days
Now, I was an English specialist and our boss promised me that there would be no math in this job, but those numbers don’t seem to me. Stay with me here. Winters were three days shorter. The spings were nine days shorter. Autumns were five days shorter. I didn’t really need to take off my socks and shoes to find out that those three seasons were, on average, a total of seventeen shorter days. But the summers were “an average of 78 to 95 more days? ”We divide the difference and say that the summers were an average of 87 more days. You may have to break your calculator, but that means that the whole year was 80 more days of what it was 59 years before. They started selling new calendars with an additional three months and I never noticed?
UPDATE: I went back and checked it and it turns out that NBC News corrected its typographical error in the last paragraph extracted above. Now read:summers went from an average of 78 to 95 days“.
Okay, so now at least the math works a little better. They are saying the summers gained 17 days, while the other three seasons lost 17.
Even if we accept these figures, the next question I had was how they “identified” the beginning and end of each season. The four stations we recognize are quite ambiguous in nature. Right now I’m at about 60 degrees relatively mild and my calendar tells me that spring officially started this weekend. So winter is over, right? But we’ve had years here where we were hit by snowstorms until the second week of May. Does this mean that in those years the winter lasted until May and the spring lasted only six weeks?
My point is that the Guan team may be able to identify the exact temperature at any weather station on a given day of the year during the period studied. But he’s talking about the average “winter” being five days shorter in a fifty-year period. I guess we only have to take his word when winter begins and ends? What kind of science is this?
There is one last point to touch on, as much of Guan’s figures are based on temperature measurements from when Eisenhower was president. The accuracy of thermometers and other measuring devices has changed over time. Maybe it hasn’t changed everything that a lot, but it has changed. And when you talk about such a small number of degrees, I remain skeptical if average temperatures rose in precise amounts to one-tenth of a degree.
In any case, I won’t complain about one more week of summer. If we could work to cut back on winter for a month or so, we would be ready.