[1] A leading pioneer in long-term multidisciplinary ecological studies, Likens examines energy flow and biogeochemical flux models in the ecosystems of forests, streams and lakes.

[1][2] In addition to its scientific impact, this work has influenced public debate and governmental policy, particularly the United States Congress's Clean Air Act Amendments of 1990.

[12][13] In 1988, Hubbard Brook was designated by the National Science Foundation as an LTER, a site for collaborative long term ecological research.

[11] Likens' work in the area is considered "one of the world’s most comprehensive studies on how air pollution and land use shape forested watersheds".

Situated at the Mary Flagler Cary Arboretum,[1] it is an independent center for ecological research, "whose work is highly relevant to policy concerns.

"[23] In addition to managing teams of scientists and educators, Likens continued his research at Hubbard Brook each summer.

In July 2012 he began a three-year term as special adviser to the president of the University of Connecticut on environmental affairs and distinguished research professor.

[24] His work has influenced the United States Congress on issues such as the Clean Air Act Amendments of 1990.

[1] In 2003, Likens and Dr. F. Herbert Bormann received the Blue Planet Prize from Asahi Glass Foundation, for "outstanding scientific research that helps to solve global environmental problems".

[12] In 2014, he received the Alfred C. Redfield Lifetime Achievement Award from the Association for the Sciences of Limnology and Oceanography (ASLO).

[21] He has won the BBVA Foundation Frontiers of Knowledge Award (2016) jointly with Marten Scheffer for contributing decisively to what the jury describes as “one of the major challenges” of this scientific discipline: to understand and, where possible, anticipate ecosystem responses to human-induced alterations of the natural environment.