Melba Lara: We've already seen some snow and cold this season but climatological winter begins in earnest this week. Every winter in Chicago is its own unique adventure. Still, there are trends we can look at to see how our typical winters are evolving as the climate changes. Dr. Trent Ford is the Illinois state climatologist, and he's joining us for our weekly climate conversation. We're going to look back at over a century of Chicago winter data. Trent. Welcome.
Trent Ford: Hey, Melba, always good to be here.
Melba Lara: So let's start off first with how has winter in Chicago actually changed over the decades?
Trent Ford: Yeah. So you know, when folks asked about climate change in Illinois, kind of the summary is warmer and wetter and And Winter has actually led that charge. So winter has gotten warmer in the city of Chicago since the turn of the 20th century. And it's also gotten wetter. But in fact, winter has actually gotten warmer and wetter at the fastest rate of all the seasons. So just to give you some numbers, the winter average temperatures between December 1 and the end of February, that average temperature's increased by about two and a half degrees Fahrenheit since the turn of the 20th century. And that compares to about 1.6 to 1.8 degrees Fahrenheit for the summer average temperature. So everything's getting warmer, but winter is getting warmer at a faster rate. And it's much of the same kind of story for precipitation as well.
Melba Lara: And Trent to be honest, fewer super cold days. Sounds really good to me. So are there any positive effects as we're seeing warming and wetter winters?
Trent Ford: Yeah, you know, the thing is, is that I mentioned the two and a half degrees Fahrenheit number, we're getting warmer by that rate, but we don't really experience winter, especially winter, in like an average temperature, we experienced it by the extremes, namely very cold temperatures, like you mentioned, and snowfall. What we've seen really, especially over the last 30 to 60 years is a significant decrease in the frequency of those very, very cold, extreme cold temperatures, we're talking temperatures in the single digits to maybe negative degrees Fahrenheit. I'll just give you an idea: so the last 30 years, we had an average about six nights per year in the wintertime, with a temperature below zero degrees Fahrenheit. That compares to 11 nights per year, between 1960-1990s We're having the number of nights below zero degrees.
Now, you mentioned the effects of that. And of course, you know, a lot of folks in Chicago say oh, the warmer winter, that sounds fantastic. And indeed, when we think about human health aspect of it, those fewer very, very cold nights that we're seeing means less exposure to very extreme temperatures, which of course can be deadly, especially for the housing insecure. And so that is one positive. However, it can also come with some negative impacts as well. And one of those is that the the the wintertime temperatures, especially those extreme temperatures in the winter, are a primary determinant of kind of the geographic range of many plants and animals. And so as we warm our wintertime, and especially to reduce the number of those very, very cold nights we have, it expands the range of some non native or invasive species of plants and animals here in Illinois, including some species, we really don't want around very much.
Melba Lara: So climate change gives and climate change takes - because we have less extreme weather that might harm people, but then we've got ticks that nobody wants.
Trent Ford: That's right. Yeah. And as you alluded to, you're one of those species that we don't really want around and we haven't had around really the last century but we're seeing more and more on the Chicagoland area is the Gulf Coast tick. And so research done here at the University of Illinois and by others, shows that the increase in Northern Range of the Gulf Coast tick which brings along a number of diseases that can affect humans, that that Northern Range really varies as as wintertime temperatures do. So as our winters continue to warm as they're projected to here in Chicago. It's likely we'll see some more exposure to these plants and animals and the kinds of not so great things that they bring.
Melba Lara: I've been speaking with Illinois State Climatologist Dr. Trent Ford. If you want to submit a topic suggestion for our weekly climate conversation you can email us at firstname.lastname@example.org This is WBEZ
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