Beginning in 1931, the Arboretum grew from 60 acres west of campus to the entire 750 acres of College property. The campus grounds crew and the Arboretum staff collaborate to maintain the entirety of the campus using environmentally friendly techniques. The Arboretum was one of the first to be dedicated to growing and studying native plants, and it now protects hundreds of acres of wild lands including tidal and freshwater marshes, swamps, fields, and forests. The Arboretum serves as a “living laboratory" and classroom for teaching and research, as well as a place for recreation. For more information and trail maps, visit https://www.conncoll.edu/the-arboretum/.

In 1993, the Center for Conservation Biology and Environmental Studies was established to offere an interdisciplinary certificate program and promote collaboration between various departments on campus. The Center was renamed in 1999 in honor of Professors Richard Goodwin and William Niering who both made enormous contributions to the field of ecology and conservation of natural areas.  As an academic center, GNCE supports research and education, offers a selective certificate program, and sponsors a bi-annual symposium. Learn more here.

Established in the early 1970s, the Environmental Model Committee is comprised of appointed staff, faculty, and students who work together to address issues such as energy conservation, greenhouse gas emissions, and waste minimization. The EMC provides leadership, develops policies, initiates programs, and coordinates community education to support College operations as models of environmental sustainability. The EMC works closely with The President's Sustainabilty Council. EMC meetings are held once a month and are open to the College community. 

In August 1999, the college became the first higher education institution to sponsor a carbon offset program. In collaboration with Reforest the Tropics Inc., a nonprofit organization in Mystic, Conn., the College agreed to work with farmers in Costa Rica to plant enough fast-growing trees, including the Klinkii (Araucaria huntsteinii), to offset the carbon dioxide emitted annually by the electricity use in the College Center at Crozier-Williams.  The 25-year contract, ending in 2024, has offset ~327 MTCO2 each year since it began.

In the spring of 2001, Connecticut College students led a campaign to purchase renewable energy. The student body agreed to add $25 per student to the annual comprehensive fee to support renewable energy. The College was one of the first in the nation to establish a fund of this sort and was a founding member of the EPA Green Power Partnership. The fund was primarily used to purchase Renewable Energy Certificates from 2002-2013. The amount of Renewable Energy Credits purchased ranged from 25% of our annual electricity use to nearly 100% in the years between 2006 and 2009. The fund was also been used for wind energy feasibility studies. In 2013, the fund was renamed the Sustainable Projects Fund and became focused on funding student-led, on campus sustainability projects.

In January 2007, President Higdon became a charter signatory of the American College and University Presidents' Climate Commitment. In 2009, the College undertook a comprehensive environmental sustainability baseline assessment (ESBA) of its operations and from 2010-2011, consultants performed an energy assessment and a comprehensive Renewable Energy Assessment. In 2022, after several years of focus on education and engagement around sustainability, the College re-committed to emissions reductions and announced a new goal of carbon neutrality by 2030.