Kurt Fristrup, bioacoustical scientist

Urban sounds and light can degrade our quality of life. This National Park Service scientist believes a remedy begins with maps. Interview by Leslie Willoughby

April 07, 2015

The Milky Way over Racetrack Playa, Death Valley National Park, California. Credit: Dan Duriscoe, NPS Night Skies Team Lead Physical Scientist
Courtesy of Kurt Fristrup/National Park Service
Visitors to national parks marvel at the Milky Way and sleep soundly through silent nights. Yet they spend most of their lives in places teeming with noise and aglow with artificial light. Can we preserve the dark and quiet retreats that remain? Yes, says a U.S. National Park Service researcher in the new field of bioacoustics—and he's traveling the country with sensitive microphones and light sensors to make his case.

“We have struggled with this relatively new concept of protecting the sensory environment,” says Kurt Fristrup. “We had to develop new approaches, new measurement techniques, and even new indicators of environmental quality for sounds.”

Fristrup works for the natural sounds and night skies division of the National Park Service in Fort Collins, Colorado. He aims to raise public awareness by charting the extent of noise and light pollution. The national maps, which also reveal sanctuaries of natural sound and darkness, will be available online within months.

Fristrup presented the maps and explained their value for urban planners and wildlife managers during the February 2015 meeting of the American Association for the Advancement of Science in San Jose. Afterward, during a road trip to the proposed Santa Cruz Redwoods National Monument along California's Highway 1, SciCom's Leslie Willoughby surveyed his plans.

You talk about precious soundscapes and dark skies as resources. What do you mean?

Today, the most immersive or expansive experiences we can have in nature are when we go to places that are really quiet or really dark, and we can see the full splendor of the night sky. You can still experience this in a handful of places in the western U.S.

When I go bird watching or looking for other organisms—even if it’s not an animal that makes a lot of sound—it’s often some sort of acoustical cue that puts me on the animal. For instance, I once saw a mountain lion. I was backpacking in the Sierra Nevada, and the first thing I was aware of is that all of a sudden the area around me got very quiet.

It’s remarkable, as you hone your listening skills, that it’s not the dramatic bird song choruses or other strikingly obvious aspects of the soundscape that grab you. It’s these subtle things, these almost incidental sounds, that can really matter in the ecosystem.

How are the experiences of children today different or the same from your own?

I grew up in Millbrae [south of San Francisco]. I was a junior in high school, probably in 1967 or 1968, and there was a comet. I used to deliver papers between four and six in the morning. I remember I was out on my bike and I crossed a little bridge in Millbrae, and the comet was hanging in the sky over Mount Diablo. I’m fairly certain that today the comet wouldn’t be visible.

Something like 60 to 70 percent of the people in the U.S. live in environments where they really can’t see the Milky Way. I think that poses a real risk of generational amnesia where these things are not immediately accessible to families. There’s a risk that this shifting baseline will affect parks as well. Visitors will come to parks that may be degraded by sound, yet it will sound so quiet to them compared to their communities. They’ll think, “Oh, our parks are in great shape. We don’t need to take action.”

It’s one reason why I talk about how important it is for us to understand sound levels on landscape scales in communities as well as in parks. If we’re ever going to make substantive improvements in acoustic resource conditions, we’re going to need action that extends far beyond park boundaries.

Is there reliable research about the health impacts of sound?

Yes. There's been extensive work in Europe to look at the health consequences of noise. Up front, we have to recognize that this is an extraordinarily difficult thing to look into. One of the criticisms I've heard leveled at the European studies is that they're so complicated. This isn’t a universal opinion, but I have colleagues who feel that way.

A multinational study in Europe has shown that at levels about 10 decibels below the level at which U.S. community regulators start mitigating noise, you begin to see an increase in the risk of elevated blood pressure and in the risk of stroke and heart attack. By the time you get above 65 decibels—the day-night average sound level at which the U.S. Department of Transportation begins taking action to build sound walls—you see quite marked increases in [these risks].

Noise management might be one of the most powerful and immediate tools to improve both the ecological function of our communities and the health and well-being of the people who live there.

What about the health effects of light at night?

"As soon as we choose to act, as soon as we choose to make a place quieter or darker, there will be immediate benefits."

There is overwhelming evidence for night shift workers that being in bright environments at night is bad for your health.

In our communities, the big problem is light from the streets hitting our windows and leaking into our bedrooms. Real darkness matters. The best conditions for sleeping are in rooms that are really dark—dark enough that you can’t walk around in them.

We turn into a valley about eight miles north of Santa Cruz. On February 12, Congresswoman Anna G. Eshoo (D-CA) introduced legislation to designate 5,800 acres here as the Santa Cruz Redwoods National Monument.

This is the middle of the proposed monument.

That is just spectacular.

I park the truck and we step a few feet off the road into a wooded area.

We're on Bonny Doon Road, about a mile from the ocean. Tell me what you're hearing.

Here, you have a demonstration about automobile traffic. Even if you could make engines totally silent, the whooshing sound of the tires on the pavement at these speeds is still going to be the dominant source. The way to make roads quieter is to change the structure of the pavement so that the tires make less sound.

So-called quiet pavement can be as much as 10 decibels quieter than this standard asphalt pavement. This means that the noise radiated from the corridor is equivalent to reducing the traffic by a factor of ten. You could have one-tenth as many cars—or you could put in quiet pavement.

We walk toward a creek.

What are you hearing now?

The sound of flowing water, one of the most universally appreciated natural sounds.

Here’s one of the ironies: I have tinnitus. No matter where I go, I hear ringing in both ears and it is compromising my ability to hear the little high-pitched chirping noises of birds. Here we go—that’s a belted kingfisher! It’s interesting. I wouldn’t think this stream would support a fish population it could exploit, but maybe there are some ponds nearby.

It’s 5:30 pm. The sun will set in 20 minutes.

What about the lighting?

I think out here where you have a lot of marine layers, it wouldn't take much light from a small town like Half Moon Bay or Davenport before you could begin to have measurable effects.

Is there a hopeful message?

As soon as we choose to act, as soon as we choose to make a place quieter or darker, there will be immediate benefits.

For instance, we have the emergence of LED lighting technology, which gives us the chance to completely re-imagine how we light our cities and our parks. We can generate light more efficiently, and we can also control the color, intensity, and direction of light in ways we never could have before. On the noise front, the emergence of electric power for cars and—potentially down the road—aircraft, could be transformational in dropping the amount of noise generated by these vehicles by an order of magnitude or more.

Starting at the level of civil awareness…

Yes, that’s the place to begin, right? The really amazing thing about the national parks is that hundreds of millions of visitors come to them each year. Suppose we’re able to re-engineer the valley floor of Yosemite. We could accommodate the same number of visitors, but it would be much quieter and much darker.

When people visit the park they would say, “It was amazing. I stayed in the Ahwahnee [Hotel], and it had all the comforts of home, yet we had this amazing night sky. When you went out at night it was quiet.” Then because we have so many visitors, so many stakeholders, it could really make a difference. That’s why I think we have a real chance—and why the Park Service has a special role to play in this discussion.

We drive back south along the coast to Santa Cruz.

How would you explain to readers what these maps are and how they can be used?

We just visited an amazing parcel of land that’s going to be put into the public domain and enhance the mosaic of natural lands on the California coast. Sometimes you get an opportunity for that kind of acquisition, and you just do it because that chance doesn’t come back. But there might be other times where you have limited funds and you have your choice of different parcels to purchase. Which of these parcels is the most important to get? One of them is potentially much quieter and darker than the other.

Towns don’t have to invest in a big sound-level measurement campaign. We can tell them right now what conditions are likely to be there, and what they should be in the absence of human-caused noise.

How does this resonate with you personally?

I’m not looking for a revolutionary change. Let’s say we had an 8 percent improvement in environmental conditions every year. That’s a very healthy rate of return. With current technology, it’s quite reasonable. That means eight years from now these pollution levels could be half what they are today. So let’s get started. Let’s change a few light fixtures. Let’s drive a few more electric vehicles, maybe even not light some places, and do a little more walking.

I think this is where my peculiar disciplinary interests also interact with a larger societal problem: How do we encourage people to be contemplative, to pause and think rather than react? One of the ways we might do this is making sure that they live in healthy restorative environments. They need the luxury of being able to reflect upon what’s in front of them.


© 2015 Leslie Willoughby. Tune into the collected writings of SciCom graduate student Leslie Willoughby at www.willoughbywriter.com.