Just how hot has it been in 2012? Answer: Very. Part Deux.
As I mentioned in the earlier blog, I wanted to make a blog discussing some of the current weather anomalies with a focus on the changing environment. Obviously, I don't purport to blame all of the current warming on climate change. The anomalies we have been observing are inextricably linked to weather patterns.
Nevertheless, I feel it prudent to discuss these anomalies in the context of climate change. After all, future climate projections often focus on how the past climate in one location might compare to a future climate warmed by an enhanced greenhouse effect. I'm sure many of you have seen maps that shift one state hundreds of miles to the south to illustrate the changes. I've seen persons skeptical of anthropogenic climate change dismiss these maps as pure fiction. It seems unfathomable to think that Chicago would see a summertime climate similar to 20th Century Memphis, Tennessee by 2050 and even hotter by 2100, as the following images from the United States EPA illustrate.
Again, these images are only for summertime temperatures. Because there is less variation from north to south during the summertime even a small temperature increase can have a significant shifting effect.
In light of the current temperature extremes, I decided to see how 2012 is stacking up. My analysis includes data from January 1 through July 15, so roughly the first half of the year. Temperatures for the year have averaged some 4 to 6 degrees above the 1981 to 2010 climatological normals for much of the Midwest, as shown in the figure below. Please note that this is a dynamic image, so the image will change with time.
So what does 4 to 6 degrees look like? We know it's been hot. Very hot, indeed. But what does 4 to 6 degrees really mean to the average person? To look at this, I decided to make a comparison. This comparison will show how the temperatures observed at Chicago O'Hare International Airport and Detroit Metropolitan Wayne County Airport this year stack up against the 1961-1990 climatological normals for Lambert Field in St. Louis and Cincinnati/Northern Kentucky International Airport. To make the comparison fair, I've only selected large metropolitan areas with similar urban heat island effects. In addition, I've used the 1961-1990 normals, as recent normals have already crept up somewhat in response to the changing climate. 1961-1990 normals for these locations can be found at the following links:
St. Louis Link
Unfortunately, I could not find a link from the Western Regional Climate Center for Cincinnati/Northern Kentucky 1961-1990 climatological normals. However, I was able to find them by looking at past LCDs from the National Weather Service.
Because of the volume of numbers, I've decided to break this down into two additional posts. In later posts, I will do a month-by-month analysis of the figures. But for now I'll just briefly state the results of the comparison.
I found that the mean temperature in Detroit for the period January 1 through July 15 has been 52.7F. The 1961-1990 normal for that period was 45.4F. The corresponding normal for Greater Cincinnati over that interval was 50.7F. In other words, temperatures this year have average 7.3F above the 1961-1990 normal and 2.0F above 1961-1990 normal for Greater Cincinnati! In fact, every month but one this year in Detroit was warmer than what was considered normal in late 20th Century Greater Cincinnati. The weather in extreme Southeast Michigan this year has resembled more closely the climate of late 20th Century northern and central Kentucky than that of its own climes.
In Chicago, the period January 1 through July 15 this year has averaged 53.9F. The 1961-1990 normal for that period was 45.8F. In St. Louis, the 1961-1990 normal over that interval was 53.6F. The temperatures in Chicago this year have run 8.1F above the 1961-1990 normals for the city, and 0.3F above the corresponding figures for the city known as the Gateway to the West. Suffice it to say, the Chicagoland region has more closely resembled the climate of late 20th Century metropolitan St. Louis than its own climes.