The graduates at the 1pm ceremony mainly gained qualifications in applied science, physical education, surveying, biomedical sciences, health sciences, education and teaching.
Those graduates with four-year degrees, in surveying and physical education, had "spent the world’s hottest four years in history" in Dunedin.
"You’ve also lived through the hottest 20 years on record," Prof Cotter, of the university’s School of Physical Education, Sport and Exercise Sciences, said.
Carbon dioxide was rising again, "with no end in sight, but we need to halve it within the next 12 years".
A researcher in exercise and and environmental physiology, Prof Cotter recalled growing up on a farm on the West Coast, "mud fighting, building huts, possuming, fishing, milking — a lucky childhood I wouldn’t swap for anything".
In those days there was "mostly play, and less sport, pressure and helicopter parenting".
And teenagers then were about a third fitter than teenagers today, on average.
In science, he had sought to understand more about what exercise was, how to optimise fitness and how to live active lives that worked with the environment.
Some people complained they did not have time to exercise, but given the major health implications, "you don’t have time not to exercise".
People could "exercise anytime, anywhere, anyhow", and any problems were mainly "just in the extremes; doing nothing or building too quickly".
People determined their own resource use, and it all made a difference.
"If you’re like me and Christmas isn’t yet on your radar, maybe don’t buy but make or do something for each other, or just be together."
Graduates should also "be gentle on yourself, each other and the planet".