Professor McMichael is part of the group Climate Scientists Australia and has taken an active role in talking to parliamentarians and their staffers about the consequences of climate change.

''We've a particular civic and moral responsibility beyond our position as scientists, to find a way of getting this information more widely understood and acted upon,'' he said.

After four decades in academia, Professor McMichael is retiring from the ANU's National Centre for Epidemiology and Population Health, but plans to keep working as a scientist in an honorary capacity.

After starting as a medical graduate in Adelaide, he did a PhD at Monash University in Melbourne and worked at Adelaide University, the London School of Hygiene and Tropical Medicine and the ANU, where a conference in honour of his career was held this week.

Professor McMichael said with the many different factors influencing humans' health it was often difficult to pinpoint blame for deaths on climate change, but patterns were becoming clearer as time went on.

''There has been an increase, year by year, decade by decade, in the number of deaths that are occurring in hot periods in summer, those periods are occurring a little more often and a little more severely, and that's been widely reported in many countries,'' he said.

But Professor McMichael said he was still optimistic that humankind could rise to the challenge of dealing with the problem, firstly because their large and complex brains enabled them to imagine the future, and secondly because if scientists did good research and communicated it, it would motivate people to pressure governments to act. ''The things that are at stake here are the biological and, of course, mental health of human populations; that ought to be a compelling point,'' he said.