What makes humans different from other species? To environmental engineer and Santa Clara University professor Stephanie Hughes, it's the fact that we produce things that can't be used again in nature. We break the cycle. Professor Hughes doesn't even like to use the word, "waste."
"I'm not very pleased with that terminology because really, humans are the only ones that have waste streams," Hughes says. "In the rest of the world, this planet operates cyclically: waste from one animal becomes nutrients for another."
For many Americans, throwing something away means that it's gone forever. But Professor Hughes wants students to learn that this is not always the case. Hughes has taken her students to tour a paper recycling plant, sewage treatment plant and household hazardous waste facility.
By training, Hughes is a chemical and environmental engineer with a particular love for sewage. She's known for cruising around campus on her bike and lending her worms to students she's inspired to start composting.
"I was kind of like a worm dealer," says Gabby Farrer, a recent grad and former Teaching Assistant. "Stephanie was giving me the worms, and I was giving them to my friends for their compost bins."
For Farrer, studying environmental science came with a side of deep existential dread. After spending the first few post-grad months applying for jobs, she now works at the California Academy of Sciences. Each day, she thinks about the future of the planet. She tries her best to live sustainably, but doesn't think we can compost our way out of this.
While the U.S. is four percent of the global population, it accounts for 12% of all trash produced worldwide, according to a 2021 report from the advocacy organization Environment America.
"That is unfair to everybody because we send our trash overseas a lot of times, especially our recyclables."
Before going to college, Farrer used to bring certain types of recycling to her high school, because she knew that not all types could be recycled at home. In taking Garbology, she learned that the system didn't work as well as she thought it did.
Plastic is hard to recycle because there are so many different types, and many of them can't be melted together. Paper can only be recycled five to seven times, according to the EPA.
"In the past I viewed it a lot as an individual effort and everybody should be doing their part," Farrer says. "And then, learning more, I realized that the best thing that I could be doing is probably making less trash. I feel hopeless at times. I feel sad. I feel frustrated. Lost. Definitely angry, but sometimes hopeful."
Right now, our planet is in the midst of the sixth mass extinction, as a large portion of distinct species are dying off. She thinks that even if humans wipe ourselves out, life will spring back. At least, that's what happened after the five previous mass extinctions.
"There is going to be life on this planet in the future. I just won't be here to see it thrive," Farrer says.
But before we just accept that as fate, things can be done in the here and now. At the individual level – people aren't great at recycling correctly. Professor Hughes has seen diapers, greasy pizza boxes and unrinsed yogurt cups in recycling bins. Most plastics, like those clamshells that berries come in, aren't even recyclable in many cities.
"All of this reduces the quality of the contents of those recycling bins," Hughes says. "And sometimes those just have to go right to trash."
Claire Parchem graduated from Santa Clara University in 2016 but still remembers a project where she found menstrual pads to be worse for the environment than tampons – due to the amount of materials they use. After taking the class, she was hooked on waste and got an internship with Waste Management. Today, she's a manager at startup AMP Robotics, which programs AI-driven robots that sort waste from recycling.
"It's like this triangle with a suction cup on it," says Parchem. "It moves almost like a spider. It's so quick in how it attacks the recycling and puts it into the different boxes."
Despite the temptation to be pessimistic about the future of the environment, students say that Professor Hughes keeps things exciting and positive.
"It feels like a mountain of dread," says Oli Branham-Upton, a junior who took Garbology in 2022. "But I think classes like this, that are specific enough to cover a certain dimension of stuff that we can control within the climate crisis, are important."
After graduating, Branham-Upton hopes to work at the intersection of racial and environmental justice.
"By the end of the course, I want students to be uplifted," Hughes says. "I want them to know that there are visions out there to move us towards a cyclical society."
This story was edited by Majd Al-Waheidi.
