Amy Boylan's picture


  by  Amy Boylan

Pollution is typically thought of as a visual, chemical, or physical substance that causes environmental harm. Often overlooked is noise pollution, which of course is a staple in densely populated cities, but it's becoming increasingly problematic as a growing din infiltrates nature and our protected areas such as national parks. And while multiple studies have shown the negative effects this form of pollution has on humans, it also has consequences on the natural world.

Noise is defined as "unwanted sound" that is measured in decibels on a logarithmic scale and has an effect on our ecosystems. Anthropogenic noise impacts predators as they hunt prey, changes animals' mating habits, causes stress in insects, and it even affects growth of vegetation. Gordon Hempton,, an acoustic ecologist, said on the topic, "You add noise pollution into the background, and the owl that's hunting at night can no longer hear the soft scratching of the rodent underneath the leaves. The consequences on wildlife are large enough that it is literally creating species shifts in natural areas."

These changes are apparent as COVID has forced the closure of national parks to visitors. The Guardian reported that last year "more than 4 million visitors traveled to Yosemite...the vast majority by way of automobile. On busy late-spring days...the 7.5-mile long valley can become an endless procession of cars." The article continues: "A handful of workers who have remained in Yosemite during the closures, who have been able to travel by foot and bike along the deserted roadways, describe an abundance of wildlife not seen in the last century. "The bear population has quadrupled," Dane Peterson, a worker at the Ahwahnee Hotel in Yosemite Valley, told the Los Angeles Times. "It's not like they usually aren't here ... It's that they usually hang back at the edges or move in the shadows."

It is unsurprising that the decline in vehicle traffic changes the habits of wildlife in national parks such as Yosemite. An article by Alex Brown recalls a study that examined this very topic: "Several years ago, Boise State's [Jesse] Barber and a team of scientists installed 15 speakers in an Idaho woodland and played traffic noises to create a "phantom road" over half a mile of terrain. They found that 30% of songbirds moved elsewhere once the noise began, and many other species that remained struggled to gain weight."

Recent shutdowns aside, national parks have seen unprecedented amounts of visitors over the last few years. Lamenting the lack of quiet found in these protected areas, Jenny Morber writes in her article, "Part of the problem is simply numbers. National parks received over 327.5 million visitors in 2019, up 9 million from the year before. Yellowstone, Rocky Mountain, Joshua Tree, Acadia: tourism is surging." And these parks are not unique in their surging attendance numbers - according to the National Park Service's news release, “Visitation to America’s national parks in 2018 exceeded 300 million recreation visits for the fourth consecutive year. The 318.2 million recreation visits total is the third highest since record keeping began in 1904.” With our growing population seeking to leave dense cities and suburbs to explore nature, a greater number of people are enjoying these protected areas, and they are not doing so quietly.

In his article about noise pollution for The New Yorker, David Owen spoke with Les Blomberg, the founder and executive director of the Noise Pollution Clearinghouse, who said, "What we're doing to our soundscape is littering it. It's aural litter—acoustical litter—and, if you could see what you hear, it would look like piles and piles of McDonald's wrappers, just thrown out the window as we go driving down the road."

But it's not just noise from visitors' cars or park patrons that contribute to noise pollution. An article in The Washington Post states that, "The noise can come from a wide array of sources — visitor center HVAC systems, air traffic overhead, growling car engines, children shrieking nearby, mining and drilling taking place miles away." It further notes that, "More than a fifth of protected areas experienced 10 extra decibels of human noise — a tenfold increase in the level of sound. The majority of areas considered "critical habitat" for endangered species were among the regions that dealt with at least an extra three decibels of sound, and 14 percent of critical habitats were in the 10-decibel category."

Unfortunately, anthropogenic noise is increasing on an even steeper trajectory than that of our population growth. An analysis performed by a team of researchers based in Colorado found that, "Between 1970 and 2007, the US population increased by approximately one third. Traffic on US roads nearly tripled, to almost 5 trillion vehicle kilometers per year. Several measures of aircraft traffic grew by a factor of three or more between 1981 and 2007." More people means more cars, more air travel, and more construction, which all contribute to the din.

As our population pushes past 330 million and protected areas lose square footage, the problem of noise pollution will only be further exacerbated. Solutions to abate noise have been implemented: paving roads with a special form of sound-reducing pavement, putting up "quiet" signs for visitors, and using shuttles to move crowds to reduce vehicle traffic. Yet, as Alex Brown states in his article, "Many of the loudest sources are transportation-related; short of tearing up highways and relocating airports, officials have no obvious solutions. And law enforcement agencies may not have the resources to patrol with decibel meters and seek out violators." Brown further references Jesse Barber from the Sensory Ecology Lab at Boise State University, who said, "Quiet advocates say it will take drastic measures just to prevent things from getting worse...the country needs to stop building new roads and increase public transportation on existing corridors. But states have little say over the interstate highway system or federal airspace." States also have little say over our country's immigration policies, which are controlled at the federal level and are the reason behind the approximately 90% of our population growth.

Noise pollution is a real issue that harms the very places meant to be protected from human interference. Any technological advancement is merely a short-term solution as more people are using the same limited resources - including our national parks. The federal government has the ability to address our immigration-driven population growth, which will bring our population to 441 million by 2065. If we do not reduce the amount of immigrants welcomed to our country each year, noise pollution will continue to echo throughout our protected lands at an increased rate as our population reaches ever higher. This will only further harm our wildlife, our ecosystem, and our ability to find a sense of solitude in nature. Former U.S. Senator Gaylord Nelson, the founder of Earth Day, said while discussing our country's growing numbers, "With twice the population, will there be any wilderness left? Any quiet place? Any habitat for songbirds?" Our population growth must be addressed to abate increasing noise pollution in National Parks.

Amy Boylan is a Content Writer for NumbersUSA's Sustainability Initiative

Updated: Thu, Jan 28th 2021 @ 5:00pm EST

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