As the Lake Michigan Shoreline Erodes, One Indiana National Park Tries to Adapt
On the southern end of Lake Michigan, Indiana Dunes National Park has seen the water levels rise five feet since 2014, hastened by human-made structures and an increase in storms brought on by climate change. Higher water marks mean more erosion to the sand dunes that have run through the area for thousands of years. PBS NewsHour Weekend’s Zachary Green reports on how the park is adapting to the new normal.
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Hari Sreenivasan:
Forecasters and scientists are predicting that the devastation caused along ocean coastlines from severe weather like hurricane Ida will become more frequent.
And they are also drawing attention to the impact the earth’s warming climate is having on non-coastal rivers and lakes, including the habitats and communities that surround them.
NewsHour Weekend’s Zachary Green visited one national park that’s trying to adapt to the new environmental normal.
This segment is part of our ongoing series, “Peril and Promise: the challenge of climate change.”
Zachary Green:
On a typical summer day at Indiana Dunes National Park, beachgoers sun themselves along the shore or take advantage of the warm coastal waters. Children run along the sand or up the enormous dunes that surround the beach.
This isn’t the ocean. It’s the southern end of Lake Michigan, an area known for its steel factories. But it’s also home to a unique ecology.
Paul Labovitz is the park’s superintendent.
Paul Labovitz:
We continue to be one of the most biologically-diverse places in the national park system, and in North America. A couple miles from here, I can take you to a place where there’s prickly-pear cactus growing next to bearberry, which is an Arctic plant, side by side.
Zachary Green:
The most eye-catching feature of park is the sand dunes that have run through the area for more than 10,000 years. They are the product of a natural process called “erosion”, when outside forces transport rock and soil from one place to another.
Paul Labovitz:
The sand dunes you see here are the product of water and wind over time, eroding sandstone into smaller and smaller particles, and then that sand moving around with wind and water. The Grand Canyon is a product of erosion. The Badlands is a product of erosion. It’s really kind of a cool thing to think about. And it’s not necessarily a bad thing.
Zachary Green:
But over the last few years, erosion along the dunes and in the surrounding area has increased in speed and intensity.
Paul Labovitz:
Four years ago, we would have been under 20 feet of sand here. This dune was continuous the whole way across.
Zachary Green:
Wow.
Paul Labovitz:
And it’s now back there as flat surface sand. That’s– this is a notch that was formed by erosion.
Zachary Green:
Last year, Lake Michigan experienced record-high water levels that washed out beaches all around its southern coast. That’s not surprising, as the lake typically rises and falls throughout a 30-year cycle.
But an increase in the number and severity of storms over Lake Michigan caused the water levels to rise much faster than normal. So much so that the beach we’re standing on now didn’t exist last year.
Paul Labovitz:
We basically rebuilt the beach probably from where this metal fence ends, straight across to where those rocks are piled.
Zachary Green:
So, basically the beach that we’re looking at right now is– is kind of man-made–
Paul Labovitz:
Oh, yeah. Yeah, yeah.
Zachary Green:
We only have a beach here because you guys basically just piled up sand.
Paul Labovitz:
Correct.
Zachary Green:
Scientists believe that one of the effects of global warming is an increase in volatile weather, like the storms over Lake Michigan. Labovitz says that, since 2014, those storms have contributed to a dramatic increase in the water level.
Paul Labovitz:
The change in lake elevation from ’14 to ’19 was five feet. So think about the volume of water in Lake Michigan at that time. I don’t even know what the trillions of gallons conversion would be. But the lake level changed five feet in five years.
Zachary Green:
And it’s not just the rise and fall of water that’s eating away at the dunes. A warming climate also means less ice in winter.
Paul Labovitz:
So when the weather gets cold but the lake’s not frozen, we’ll get a gigantic layer of ice built up on the beach. Could stack 40, 50 feet high. That ice protects the lakefront from erosive forces of waves through the winter. Well, if we don’t have it, and you get a big storm that whips up in the winter, there’s nothing to protect the dune from tho– those waves.
Zachary Green:
But Labovitz says the biggest factors speeding up erosion on the dunes are residential and commercial structures built on the waterfront that change the way sand flows into and out of the lake, such as the two large harbors that sit on either side of the park.
Paul Labovitz:
Those two projections into the lake have interrupted the way sand moves naturally from east to west on the lakefront to replenish the beaches. We actually put sand here, artificially, to replace some of that sand that wasn’t being deposited there naturally.
Zachary Green:
All along the coasts of Lake Michigan, homes and buildings are literally sliding into the water due to a combination of lake level rise and the eroding shoreline.
Labovitz says that climate change could actually play a role in stopping further construction along the lakefront. More intense weather from the warming climate could cause water levels to not just climb higher, but stay higher for longer—although he says it could also have the opposite effect.
Paul Labovitz:
The good news is, well, if it gets that high and stays high, maybe people will learn and stay away from it. But if it comes down low and stays low longer, the memory lapse kicks in and we could build up to the lake and then repeat as necessary.
Zachary Green:
Labovitz says that the staff at Indiana Dunes National Park are working to educate visitors about the behavior of Lake Michigan and about how limiting development along the shore can actually help the dunes weather the changing climate.
Paul Labovitz:
The dunes are made to erode and build up over time to absorb that– change in lake level and lake energy. So again, the– the most resilient lakefront is a natural lakefront. And so we as people continue to try and test that, and I joke and I say, “The lake always wins. Always.”
