Transcripts

text | pdf |

---

[MUSIC PLAYING] TOM WEBER: Good morning. This is MPR News. I'm Tom Weber. On Fridays, we bring you our favorite documentaries. And we're going to start this week with an in-depth look at climate change in Minnesota.

We were very excited to learn this week that an MPR News reporting project on that topic won a prestigious Silver Award from the American Association for the Advancement of Science. This report was produced last winter when my colleagues Dan Kraker and Elizabeth Dunbar traveled the state to see firsthand how a warming climate is already changing the places we live, work, and play.

So for the first half of this hour, we'll listen back to their Special Report from last February. Now an award winner, it's called "Climate Change in Minnesota," here's our climate change reporter, Elizabeth Dunbar.

ELIZABETH DUNBAR: In 2012, nearly 10 inches of rain poured through Duluth during a massive storm. Here's how my colleague Dan Kraker described the scene.

DAN KRAKER: I'm standing behind the Whole Foods Co-op on the East Hillside in Duluth, about six blocks up from Lake Superior, where a huge retaining wall about 20 feet tall has been totally washed out. There's a gaping hole about 25 feet wide where a creek that normally runs underneath the parking lot here has totally washed at that wall. It's a running, muddy torrent of chocolaty, fuming water.

ELIZABETH DUNBAR: That must have been an amazing sight.

DAN KRAKER: It was. I'll never forget that day. Some streets were so ripped up, it looked like a war zone.

ELIZABETH DUNBAR: And do you remember how just a few months before that, Minnesotans were basking in the warmest March on record.

[MUSIC PLAYING]

I found this YouTube video. It shows people wearing shorts and tank tops in 80-degree weather at the St. Paul Saint Patrick's Day parade.

DAN KRAKER: That was surreal. And I know it was just one day. But if you look at temperatures across Minnesota, winters are warming significantly.

ELIZABETH DUNBAR: And the Duluth storm was just one storm. But lately, we've seen more downpours that flood homes and overwhelm roads and culverts.

DAN KRAKER: Species like moose and lake trout that love cold climates are disappearing. Maples are migrating north. Bugs that used to be killed off by cold winters are destroying tens of thousands of acres of forest. Lake Superior is one of the fastest warming lakes on the planet.

ELIZABETH DUNBAR: This is Minnesota's reality today. The climate has irrefutably changed. The statistical evidence is staring us in the face. It's happening now, not off in some distant future.

DAN KRAKER: And what's more, the changes we've already documented, they're expected to accelerate. But those changes can be tough to grasp.

GREG SPODEN: People tend to grab a hold of what's happening now and offer that up as evidence of a trend either upward or downward in temperature precipitation.

DAN KRAKER: Greg Spoden is Minnesota's state climatologist. He says when it's hot, people point their finger to climate change. When it's not, he hears this.

GREG SPODEN: Hey, it's very cold today. Where is your climate change buddy?

ELIZABETH DUNBAR: So those sounds of weather events you heard earlier, they're examples of the types of extreme weather we're more likely to see as the climate changes. But we've always had floods and heat waves so we can't pin any single event to climate change, at least not without doing a complex analysis.

DAN KRAKER: But what we can do is analyze Minnesota's long climate record to pick out trends and how the average weather has changed. First, though, you need to understand the difference between weather and climate.

COMMENTATOR: Hefty is hitting at 333 so far against Breslow--

DAN KRAKER: Think baseball. Here's how Spoden explains it.

GREG SPODEN: Weather are the individual at bats and individual games. The batting averages and the long-term statistics are the climate. And that's where we come in. We're Mother Nature's scorekeepers.

PAUL HUTTNER: This is day number nine of subfreezing temps consecutively in November here in the record. Of course, 15 days set back in 1880.

ELIZABETH DUNBAR: So when you hear MPR News meteorologist, Paul Huttner, describing the frigid stretch of days we had last November, you can't cry foul on global warming. Spoden says that'd be like giving up on a player after just one game.

GREG SPODEN: If your best hitter goes 0 for 4, that's not necessarily a trend, and you're not going to trade him or cut him. It's a body of work over the course of a season or many seasons.

ELIZABETH DUNBAR: Minnesota has weather data going back even further than baseball statistics. That long record is how we know Minnesota's climate has changed.

DAN KRAKER: The National Weather Service now has a network of 163 observers in Minnesota. Like clockwork, the volunteers send in daily temperature and precipitation data.

ELIZABETH DUNBAR: That includes Milan. It's a town of 350 in western Minnesota with deep Norwegian roots. Luther Opjorden's farm is the local source of weather information here.

LUTHER OPJORDEN: They were born Memorial Day.

ELIZABETH DUNBAR: Three kittens follow Opjorden on his daily visit to the temperature house. It's a white box overlooking the farm. Two large glass thermometers inside record the daily high and low temperatures.

LUTHER OPJORDEN: You spin the bottom one to bring that down to 48. So it's ready for taking your temperature for the next day.

ELIZABETH DUNBAR: Opjorden has recorded temperatures as low as 33 below and as high as 100. Those extremes don't tell us much about the climate in Milan. But Opjorden's family has been at this for three generations. And their combined 121 years of daily weather observations do reveal a trend. On average, the temperature is about 2 degrees warmer than when Olaus Opjorden made his first observations here in 1893.

DAN KRAKER: And that's just one of several dozen sites in Minnesota with weather observations going back a hundred years or more. So when we say that climate change in Minnesota is real, that it's here now staring us in the face, we can say that so confidently because of all of this data, these real weather observations collected by hundreds of volunteers throughout the state every day going back to the 1800s. That data proves two major ways the climate has changed in Minnesota. We're dealing with heavier rains and it's getting warmer, especially in the winter.

ELIZABETH DUNBAR: Let's start with temperature. Average annual temperature in Minnesota has warmed by about 2 degrees. It ranges from 1.3 degrees in south central Minnesota to 2.8 degrees in north central Minnesota. Those might not sound like very big changes, but a few degrees can have a major impact. How do we know? From another group of astute observers in Minnesota. They're documenting changes they see in everything-- from plants and animals to lake ice.

DAN KRAKER: Earlier this winter, I headed out with John Latimer on a thin layer of ice on Crooked Lake near Grand Rapids. Latimer dug into the ice with a jack knife.

JOHN LATIMER: I'm already 2 inches down, so it's pretty thick.

DAN KRAKER: Of course, the DNR recommends 4 inches to stand on. So Latimer, he tries to reassure me.

JOHN LATIMER: 2 inches will hold anybody.

DAN KRAKER: And he should know. For the past three decades, he's carefully tracked the seasonal changes of the natural world around his home, including the date every year when Crooked Lake freezes over.

JOHN LATIMER: Well, this lake has been on average a half a day later a year for 30 years. So it's 15 days later now than it used to be.

DAN KRAKER: That's pretty significant. I mean, that's pretty--

JOHN LATIMER: Oh, that is significant. Yeah. Half a day a year is amazing.

ELIZABETH DUNBAR: Latimer isn't the only one seeing changes in lake ice. Ice cover on Lake Superior has declined by nearly 80% since the early 1970s. And the Minnesota Department of Natural Resources has noted a trend toward lake ice melting earlier in the spring.

DAN KRAKER: So when you combine all these real world observations with almost two centuries of weather data, you not only prove Minnesota's climate has changed, you understand it really means something. And those changes are even more pronounced in the winter. Average winter overnight lows have warmed by roughly 5 degrees since 1970. And we aren't seeing as many record-breaking cold days.

ELIZABETH DUNBAR: And the warming trend gets more pronounced as you travel north.

PETER SNYDER: Northern Minnesota is definitely bearing the brunt of that.

ELIZABETH DUNBAR: University of Minnesota climate scientist, Peter Snyder, says one possible explanation is the snow and ice that cover northern climates in the winter act like a mirror. They reflect the sun's rays outward. It's one reason why skiers and ice anglers often wear sunscreen. Without ice and snow, the heat from the sun gets absorbed.

PETER SNYDER: High latitudes when it's warming, you can get less snow. And then the fact that you have less snow uncovers the surface below it, which might be less reflective. And that causes additional warming, which melts more snow. And it goes around and around.

DAN KRAKER: What's happening in Minnesota fits with the global trends we're seeing. Global temperatures are up about a degree and a half over the past century, primarily because of the increased burning of fossil fuels. That's increase the amount of heat trapping carbon dioxide in the atmosphere by 40% since the 1800s.

Overwhelming evidence shows we're the primary cause of the rapid warming over the past 50 years. Natural factors like the sun and volcanoes, they could be part of it. But the vast majority of scientists say it's just not possible they're the only cause.

ELIZABETH DUNBAR: Those warmer temperatures mean changes in where trees and plants can grow. Farmers are planting corn in northwestern Minnesota in northern North Dakota where it used to be considered too risky to grow. The growing season in the Twin Cities is longer by several weeks since 1970. And some tree species, they seem to be migrating north.

DAN KRAKER: The portage trail in the Hegman Lake and the Boundary Waters back in October was carpeted with red and gold maple leaves. It's a gorgeous patch of forest off the Echo Trail near Ely. Old growth red and white pines tower overhead and underneath sprouting everywhere are the slender trunks of red maple trees.

CHUCK WICK: The leaves are down now, but the gray stems show up very well. And those are all red maple.

DAN KRAKER: Chuck Wick, a retired Vermilion community college instructor from Ely has been observing the forest here for four decades.

CHUCK WICK: But there's always been red maple here. It's hard to say quantitatively how much it's increased. But anecdotally, it certainly seems like it's on the rise.

DAN KRAKER: University of Minnesota forest ecologist, Lee Frelich, says Wick isn't just seeing things. In his research elsewhere in the Boundary Waters, Frelich has counted many thousands of red maple seedlings per square mile. Meanwhile, he says the pines are getting old.

LEE FRELICH: And when those pines go, when they die, which they inevitably will, they're not going to be replaced by other pines. They're going to be replaced by red maple, which is already there waiting to take over.

ELIZABETH DUNBAR: Minnesota's beloved Northwoods, the boreal forest of red and jack pine, spruce, birch, and aspen, those trees are at the southern edge of their range. And as the climate warms, their range is expected to shift northward. Taking their place will be maples, oaks, and probably less desirable plants that invade and spread really fast like buckthorn.

DAN KRAKER: Scientists sometimes refer to winners and losers under climate change. That's because some species won't tolerate a hotter Minnesota while others will be more fit to survive. And some populations might even explode like bugs. Here's DNR forest health specialist, Jana Albers.

JANA ALBERS: We like to think of them as the bellwethers of climate change because they're the ones that are most sensitive to these changes in the environment.

DAN KRAKER: Bugs like the deer tick which transmits Lyme disease. The number of Minnesotans diagnosed with the disease has more than tripled since the mid-'90s in part because of an expanded tick range.

ELIZABETH DUNBAR: So bugs and maples are winners. Trees like red pines, losers.

DAN KRAKER: Yep. And it turns out, Minnesota has a lot more of these winners and losers than other states. That's because three major distinct ecosystems all come together here-- the prairie, the boreal, and deciduous forests. And it's at the edges of those where species will be most vulnerable to a change in climate.

ELIZABETH DUNBAR: Species like Minnesota's iconic moose. They're living at the southern edge of their range, but they're disappearing. They've dropped from about 8,000 to 4,000 in the northeast corner of the state in less than 10 years. Researchers believe climate change is likely part of the reason. The Minnesota DNR is halfway through a landmark study trying to tease out what exactly is causing the collapse.

DAN KRAKER: Here's where we are so far. We know Minnesota's climate has already changed significantly because of these detailed climate records we have dating back to the 1800s. One of the main changes we've seen is that it's gotten warmer mainly in the winter. And that's had profound impacts already on forests, lakes, human health, and plants and animals.

[RAIN POURING]

Now, the other dramatic change in Minnesota is in rainfall.

ELIZABETH DUNBAR: Minnesota is wetter. But the even more profound change is how it rains. In this changed climate, when it rains, it's more likely to pour. In fact, there's been a jump in the number of 2 and 1/2 to 3-inch rain storms.

That might not sound like much, but that's a heavy rain. Until recently, you'd typically expect to see only one of those every five years wherever you live in Minnesota. Researcher Ken Kunkel at the National Climatic Data Center compiled the long-term data on these storms in Minnesota and the rest of the country. What he found was striking.

KENNETH KUNKEL: The last decade actually has the largest number of these events since the network began in the late 19th century.

DAN KRAKER: Kunkel says in the last 50 years, Minnesota and the rest of the Midwest have seen a 37% increase in the amount of precipitation falling as heavy rains. So the question is why?

PETER SNYDER: There's more energy in the atmosphere. There's more moisture in the atmosphere at a given time. We call it juice.

DAN KRAKER: That's the University of Minnesota's Peter Snyder again.

ELIZABETH DUNBAR: Hold on, Dan. That extra energy or heat in the atmosphere, it's connected to rainfall?

DAN KRAKER: Yep.

ELIZABETH DUNBAR: I think this calls for another baseball analogy.

DAN KRAKER: Go for it.

COMMENTATOR: And the 2-1 pitch. Breaking ball hit deep to left field.

ELIZABETH DUNBAR: In 1998, Mark McGwire and Sammy Sosa were chasing the single season home run record.

[CROWD CHEERING]

DAN KRAKER: I remember. It was one of the most exciting seasons ever.

ELIZABETH DUNBAR: Of course, McGwire became one of several high profile players who later admitted using performance enhancing drugs. And though no individual home run can be credited to drug use, I mean, you'd expect McGwire to hit some number of home runs. The stats show players hit more home runs during the juicing era. So just as steroids supercharge baseball statistics, human influence global warming has supercharged our rainy days. Peter Snyder says that's because a warmer atmosphere holds more water vapor.

PETER SNYDER: We have more energy and more moisture to work with. So that if we have all the ingredients that we need to produce a thunderstorm, that thunderstorm ought to produce more rainfall.

DAN KRAKER: That might be what happened in 2014 in Southern Minnesota. University of Minnesota Extension educator, Jeff Vetsch, oversees a weather station in Waseca that's collected data for 100 years. And June 2014 was especially remarkable.

JEFF VETSCH: Our wettest month ever in 100 years of records. We had three days with 2 inches of rain in a four-day period. That had never been reported by an observer in our state ever.

ELIZABETH DUNBAR: When several 2- or 3-inch storms happen in the same week or month, they can cause some serious damage. Across southern Minnesota, the wet weather wiped out crops and overwhelmed wastewater systems. Sewage had to be pumped into lakes. The rain flooded basements, bike trails, and caused a mudslide on a Mississippi River bluff near the University of Minnesota Medical Center.

DAN KRAKER: Huge storms that dump at least 6 or 7 inches of rain in a day and cover a huge geographic area are also becoming more frequent. State climatologist Greg Spoden.

GREG SPODEN: We've looked at historical records, diaries, newspaper accounts. And we found a dozen or so of these mega rain events.

DAN KRAKER: That since Minnesota became a state in 1858.

GREG SPODEN: About five of them have occurred just in this century.

DAN KRAKER: Which means Minnesota saw seven mega rain events in its first roughly 140 years and five in just the last 14.

ELIZABETH DUNBAR: And of those five, three were unprecedented. They pummeled Southern Minnesota in 2004, 2007, and again in 2010. During that 2007 storm, 15 inches fell on the town of Hokah, the largest 24-hour rainfall total ever recorded in the state.

DAN KRAKER: In Stockton, floodwaters carried an entire house three blocks through town. Sean Wehlage stood on his family's roof when the house floated past.

SEAN WEHLAGE: They were on their house screaming. I shined them with a flashlight off the top-- off my rooftop. And it was like the Wizard of Oz. That house was like turning in slow motion. They were on top screaming. And we had our flashlights on them. Nothing we could do.

ELIZABETH DUNBAR: Scientists don't know why these super destructive storms are suddenly becoming more frequent.

DAN KRAKER: It's one of the many climate mysteries they're still trying to solve. That extra water vapor, the extra juice in the atmosphere, they think that alone can't explain the really big storms.

ELIZABETH DUNBAR: So here's what we know. We know conclusively that climate change has already had major impacts on our winters.

DAN KRAKER: They're getting warmer.

ELIZABETH DUNBAR: And our precipitation patterns.

DAN KRAKER: More of our rain is falling during bigger downpours.

ELIZABETH DUNBAR: But there's still a lot of uncertainty. There isn't much definitive proof yet that ties climate change in Minnesota to humidity-- tornadoes, hail, and major droughts.

DAN KRAKER: What we know is that the concentration of carbon dioxide in the atmosphere has reached unprecedented levels. And we know that carbon in the atmosphere has a greenhouse effect on the planet by trapping heat. Those conditions could change the odds of nearly everything. Here is Ben Santer. He's a climate scientist with the Lawrence Livermore National Laboratory in California.

BEN SANTER: Well, the idea that somehow extreme events-- droughts, flooding-- would be completely unaware of those large scale, human-caused changes is absurd. At some level, those things must be affected by large-scale changes in the temperature and moisture of the atmosphere.

DAN KRAKER: But how?

ELIZABETH DUNBAR: Scientists are trying to figure that out. It's incredibly complicated. Here's one of the main questions they're trying to answer. Is Earth's climate becoming more variable?

DAN KRAKER: It sure seems like it is in Minnesota anyway. Remember January 2014?

REPORTER 1: The polar vortex is a region of very cold air that forms in the northern hemisphere over the arctic.

REPORTER 2: The cold has caused many schools across the state to remain closed today.

REPORTER 3: Minnesotans are tough like this woman out de-icing her car in just a shirt. But it's fair to say, even they have now had enough.

ELIZABETH DUNBAR: The North Pole seemingly moved south over Minnesota. Wind chills hit 60 below. We were stuck in a deep freeze for days.

DAN KRAKER: Well, it turns out there could be a link to weather patterns like the polar vortex and climate change. Here's how. A lot of our weather here in Minnesota, it's created by jet streams. Jet streams are like rivers of wind high up in the atmosphere. They're caused by the difference in temperature between the poles and the tropics.

ELIZABETH DUNBAR: With climate change, the Arctic is warming much faster than the tropics. Scientists like Rutgers University researcher, Jennifer Francis, say that may be causing a wavier jet stream.

JENNIFER FRANCIS: Those larger waves in the jet stream tend to move more slowly from west to east.

ELIZABETH DUNBAR: So if a weather system is moving more slowly, I asked her, do things like rain storms or cold fronts get stuck in place?

JENNIFER FRANCIS: Yes. That would be the sort of endpoint of this whole process would be once those waves get quite large, then the weather patterns can become so slow that in effect, they get stuck.

ELIZABETH DUNBAR: Which could explain why the bitter cold never seemed to end last winter.

DAN KRAKER: But Francis warns, this hasn't been proven. And there are other factors that could be influencing the jet stream. It's a hot area of research right now trying to explain how climate change affects weather by changing the jet streams behavior.

Scientists are very confident about those overall trends we've talked about with temperature and rainfall. But this third impact, variability in weather patterns, it's a lot tougher to nail down. Slowly though, scientists are learning more about how our climate works and how human influence will play out in the future.

REPORTER 4: We have Dr. Mark Seeley with us and welcome.

MARK SEELEY: Thank you very much.

ELIZABETH DUNBAR: University extension climatologist, Mark Seeley, has been speaking about the urgent need to confront climate change in Minnesota since the '90s. He's given hundreds of presentations about Minnesota's changing climate to everyone-- farmers, public health workers, and the state environmental quality board in June 2014.

MARK SEELEY: The realm of change that is occurring is beyond any pace of change we have detected in the instrumental record. The statistical evidence for climate change is here and now. It's already present. It's already been analyzed by myself and several others. It is in our face. It's right before us.

DAN KRAKER: So while one corner of the state gets drenched, another is stuck in drought. Winters increasingly feel more like Nebraska than the Nordic playground we remember as kids. The Minnesota we know today, it will likely be a very different place in the future if you want to catch trout.

ELIZABETH DUNBAR: Or spot a moose.

DAN KRAKER: You might have to head to Canada.

ELIZABETH DUNBAR: Or the zoo.

DAN KRAKER: The science tells us Minnesota's climate has indisputably changed and will keep changing.

ELIZABETH DUNBAR: And just as the Native Americans and later the European immigrants learned to live here, so will we. In fact, people in communities across the state are already adapting to the changing climate.

DAN KRAKER: Dan Kraker.

ELIZABETH DUNBAR: And Elizabeth Dunbar, Minnesota Public Radio News.

TOM WEBER: That documentary first aired back in February as part of an extensive reporting project that we learned this week earned a Silver Award from the American Association for Advancement of Science. That's why we wanted to play it for you again here today.

Now, if you want to get involved in our next big environmental reporting project, here's how. We're starting to look into the future of water in our state from drinking water to irrigation to aquifers to fishing. What questions do you have about the way we use water in Minnesota? We want your insight. So share it at mprnews.org/water.