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Stephen Carpenter next to lake

Stephen Carpenter, director of UW-Madison's Center for Limnology, with the frozen surface of Lake Mendota behind him last month, champions the scientific method to counter "fake facts."

As an antidote to a proliferation of “fake facts,” Stephen Carpenter offers repeatable, observable, measurable science that is provably fact-filled.

Carpenter, a zoology professor, has led UW-Madison’s Center for Limnology for the past eight years. He has studied lake science, with a focus on Madison-area lakes and another lake group up north, for three decades.

But in some ways, he says, what he’s learned may be less important than how he’s learned it: through the indispensable scientific method.

“A really important message in these times of ‘fake facts’ is that there actually is a way to obtain correct information, and that’s because of science,” said Carpenter, 64. “It still exists, and we’re still over here doing it. When the public gets tired of ‘fake facts’ and wants to come back to work with actual facts, we’ll be here.”

Limnology is the scientific study of inland waters: lakes, rivers, wetlands and groundwater.

What’s the single biggest thing harming the lakes?

For the Madison lakes, it would be the phosphorous. Reducing the phosphorous input would allow us to make progress on dozens of other problems.

Phosphorous pollution from farming became a big deal first in the 1950s and has increased pretty steadily since then. I would say quite honestly there has been zero progress on the phosphorous problem.

To take some of the edge off that statement, climate change is working against us. It’s wetter, we’re getting more precipitation and we’re getting bigger storms in the Madison area, and those bigger storms and more rain would tend to wash more nutrients into the lake.

What’s probably happened is the management we have done (to control phosphorous) is just running in place.

So there’s no hope to change things?

What gives me hope is this is an area where there’s an incredible entrepreneurial spirit and drive to innovate in our watershed management. And we have the science to back it up. Because of the university, there are ... things being tried, innovative tillage practices and so on.

We’re doing exactly the right things toward solving a problem that nobody knows how to solve. There’s actually no place in the world that has yet solved the farm runoff problem, but most places in the world aren’t even trying. We’re trying, and we’re trying new stuff and cool ideas and we’re doing it in a scientific way. So that gives me some hope that we’re going to solve it eventually.

What other sorts of questions are you working on?

Trying to understand the walleye decline in northern Wisconsin. Hundreds of lakes north of Highway 29 have been losing their walleyes since 2006. So a group of us at UW-Madison and UW-Stevens Point and at the Wisconsin (Department of Natural Resources) ... we’ve actually been able to partly piece things together.

The overarching cause is climate change, but there are also several other things going. There has been loss of habitat from a number of lakes up there due to shoreline development and changes in zoning. There is also a significant harvest of walleyes (by people fishing). It’s probably the most prized table fish in Wisconsin.

With the DNR often being a partner, does what many see as its anti-science turn concern you?

The DNR is a crippled organization now. But it’s important to realize that the employees who remain are as good as they ever were. They want to serve the public. They want the environment to be better, and they’re very capable.

The problem is there’s a lot less of them now, and that’s a very serious loss. The DNR going out of the science business is going to be extremely harmful to the water resources of the state and there’s no sugar-coating that.

Do you feel like not enough people are listening?

We do a lot of public outreach, we do open houses and I give a lot of presentations, and what I’ve encountered is a real curiosity and a real hunger for scientific information about our water resources. I’ve actually found that people are pretty smart, and if I can explain it clearly, they get it.

It does seem sometimes that there’s a tendency to just get rid of the science, because it’s the messenger of bad news. But we are not the managers. The science is just telling people the facts and logical consequences of their actions. Then it’s really up to the duly elected decision makers, following the public will, to solve the problems.

— Interview by Karen Rivedal