Cool Schools at 15 Years, by the Numbers

Check out the data that's gone into 15 years' worth of Cool Schools

By Katie O'Reilly

September 9, 2021


Photo courtesy of UC Irvine, the university that holds the distinction of ranking in our top 10 Cool Schools for 12 years in a row.

Fifteen years spent doing anything will invariably make you better at it. And so it goes with Sierra’s ranking of America’s most sustainable colleges and universities. 

When we launched Cool Schools in 2007, most campuses were just starting to take stock of their efforts to protect the planet, and we covered only 10 colleges. Many schools didn’t have dedicated sustainability offices, nor eco-centric gen-ed course requirements. In the Cool Schools stories of yesteryear, we used to report on a lot of gardening clubs, recycling initiatives, and Earth Day parties. Fast-forward to 2021, and achieving carbon neutrality; divesting from fossil fuel companies; training students to work in regenerative agriculture, renewable energy, and sustainable transportation; and bringing in environmental-justice speakers and activists is practically de rigeur in academia.

Not only is the climate crisis far more emergent today, but also school administrators have become more fully aware that prospective students are seeking out those institutions that can optimally prepare them to thrive in—and improve upon—a rapidly warming and transitioning world. It's why we take our annual ranking—and the stories we tell about these schools—very seriously.

Today, we administer a 64-question survey that engages the participation of more than 325 universities. We run their answers through a custom-built algorithm that spits out a score for each school. (Our yearly ranking has helped higher-ed institutions justify establishing sustainability departments and securing money for things like solar panels, ground-source heat, and living roofs.) We've been tweaking our scoring system since the beginning—adding questions that encourage schools to divest from dirty energy and more heavily weighing energy-use questions. To earn points, schools must be making measurable progress toward using more renewable energy and supporting less fossil-fuel-reliant infrastructure. Over time, these improvements have shaken up our litany of finalists.

Over the past 15 years, Sierra's Top 10 Cool Schools have come from every part of the United States and, starting in 2019, many parts of Canada too. The greenest schools by our standards range in size from 350 students (at College of the Atlantic) to 129,000 (at Arizona State University). The below visuals reveal patterns we’ve gleaned over the past decade and a half—check out these depictions of the frequency and geographic origins of our top 10 finalists over 15 years.

To browse all of Sierra's Cool Schools rankings for the greenest colleges and universities over the past 15 years, visit the Cool Schools Archive.