Climate change expected to hit Minn. with rising temps, moving forests

Every Thursday, MPR meteorologist Paul Huttner joins The Daily Circuit to talk about the latest research on our changing climate and the consequences that we're seeing here in Minnesota and worldwide.

This week on Climate Cast, we talked about 2012 being the 10th hottest year on record globally and a new forecast that predicts Minnesota's average temperature warming 5 degrees by 2050 with current greenhouse gas emissions.

Here is an edited transcript of the conversation:

Kerri Miller: I know you were going to that big meteorological meeting last week. You were talking about flooding there, right?

Paul Huttner: We were talking about a lot of different things, but yes flooding, Hurricane Sandy was a big focus. One of the things with Sandy that we're seeing of was the unusual track the storm took, and did climate change play a role in that. But extreme rainfall events increasing in Minnesota and the upper Midwest -- that's one of the things that we're seeing a definite signal for.

Miller: You called the news that we're going to talk about here, about Minnesota from the climate assessment committee, "climate shock," on the Updraft blog. Why?

Huttner: Shocking I think because of the rate of change. We've known that the climate is warming; we've known that Minnesota is going to get warmer. In fact, we've already warmed 2 to 4 degrees in Minnesota in the last 30 years. So this last year a little more like living in Omaha, Neb. with temperatures about 5 degrees above average in the Twin Cities.

But this new report, which is a national climate assessment just out last Friday: 240 authors, 30 chapters, agencies like NOAA, NASA, the Department of Defense, predicting for the Midwest a 5-degree temperature rise by 2050. That's happening faster than a lot of the IPCC reports predicted initially. So, this warming that we're seeing, these projections actually were conservative. The warming appears to be happening faster. And if we get 5 degrees additionally of warming in Minnesota between now and 2050, that's going to have some pretty remarkable effects.

Miller: We're going to talk about that in a minute, but are other parts of the Midwest warming at such an accelerated rate, or is there something about where we sit in the Midwest that we're seeing something unusual?

Huttner: Yes and yes. Other parts are warming at a fast rate, but Minnesota is one of the fastest warming states in the country. It's the third-fastest warming state since 1970. And it turns out, and I heard a presentation from the chief climatologist with Environment Canada a couple of months back, that southern south central Canada, Minnesota, this center part of the continent -- one of the fastest warming areas, even more so than areas farther to the north. So the center of the continents away from the ocean seem to be experiencing the most rapid climate changes.

Miller: I think we should talk about what it's going to mean for Minnesota. And this is on the spectrum from the way we raise crops here, to what it means for Minnesota's ecology, right?

Huttner: Absolutely. In fact, one of the changes that really caught my attention and I think will grab Minnesotans by the heart is that our forests will be shifting. The pine forests that we love in northern Minnesota that are a signature of our state may shift north and east into Canada and those may be replaced by hardwoods, maple, birch, different kinds of trees. The hardwood forests now that are through the Twin Cities probably will trend more toward prairie biome. So, as precipitation and temperatures change, the trees like to live in a certain climate regime, they're going to move as the climate changes.

Miller: That's also going to mean differences for wildlife, right? Because different forests support different kinds of wildlife.

Huttner: Very much so. And different wildlife can adapt at a different rate. So some of them will just move, some of them may have trouble surviving and we're seeing those changes already in Minnesota. The moose population in northeastern Minnesota under stress because with temperatures not getting as cold as they used to in the winter, there's been an explosion of ticks in the northeastern part of Minnesota and that has had a negative impact on moose populations.

Miller: I noticed that our night temperatures and our winter temperatures is where you really notice this acceleration of warming. Do we know why?

Huttner: It's just the nature, I think, of the way the gases in the atmosphere are changing. They tend to trap heat and do a more efficient job of holding it at night. No, we don't understand all the nuances of why the climate is changing the way it is, but these are now observations that we have 20-30 plus years of seeing and some trends are starting to emerge. Warmer winters, and especially nights during winter, are one of those trends.

Miller: The other news that came in comes from NASA and NOAA: They report that globally 2012 was the 10th warmest on record. This was interesting: Also the warmest La Nina on record.

Huttner: That's right. La Ninas are known for cooling the planet. And this one did not do a very good job of it. In fact, we had our 10th warmest year last year, globally speaking now.

If you start looking at the numbers it just becomes pretty remarkable. Let's boil this down to a number: 36. That's the number of years since the last cooler-than-average year globally. 1976 was the last year that we were cooler than the 20th century average. So if you're 36 years old or younger, you have never lived on this planet through a cooler than average year. The 10 warmest years have all occurred since 1998. Twelve of the 14 warmest years since 2000. Every year since 2000 has been in the top 14 warmest years. Twenty in the past 25 years. And each of the past three decades has been warmer globally than the previous decades. So from the 80s to the 90s to the 2000s.

If you look at that as a natural occurrence, that's a one-in-a-billion shot. You would expect in any natural system you're going to have some above-average, below-average years. To have that many decades in a row where the climate is consistently warming, there's something else going on there.

Miller: When I was looking at the NASA map on this, you see how this is having different effects around the planet. Drought a major problem obviously here in the United States, but in places like Brazil and eastern Russia where they've never had a problem with that. Then you have really wet places like the U.K. They are begging for a very nice summer this year because over the last two summers they've had very wet years. So we're going to see how this is going to affect different places in the world quite differently.

Huttner: Right, and that's why we call it climate change. That's why climate change is a better term than global warming because the changes aren't consistent. It's not always warmer everywhere and the changes in precipitation are one of the key things.

Back to this AMS conference I was at last week, one of the things they're starting to see is the warming planet is effecting the global circulation. So our jet stream patterns are changing. That's a bit of a wild card. We don't know exactly how that's going to affect these precipitation patterns around the globe.

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