If they watched people walking past the cafe and couldn't think how they were making a difference to their lives, they needed to rethink the focus of their work.

The question is one the former Geoscience Australia chief scientist and newly inducted officer of the Order of Australia arrived at after years of work.

Looking back on his career, he wish he'd entered the world of geophysics with knowledge less skewed towards maths and science.

"I needed a better understanding of the world around me to know how to make an impact with the work I was doing," he said.

The son of a Canadian farmer contracted to build irrigation in the Sudan, Dr McFadden was born in Khartoum and was living in Rhodesia (now Zimbabwe) when a calling to science made his career an easy question.

"I was lucky enough to be one of those people dumb at everything else," he laughed.

As conditions deteriorated in Rhodesia, he moved to Australia and entered the Bureau of Mineral Resources, which evolved into Geoscience Australia, charged with mapping the country's geology and resources.

Dr McFadden, living in Fisher, said a sense of gratitude has driven his work and pro bono efforts.

"Having lost my country and then coming here to Australia, it gave us a good home, gave my wife and me good careers, it was a good place for my daughter to grow up, and I feel a deep need to give back to the country," he said.

The geophysicist was heading the peak geosciences agency's scientists when he led the team that gained federal government funding to build the Australian Tsunami Warning System, and oversaw its design.

Outside the agency, he developed the first national decade plan guiding the country's geoscience work, which brought $500 million in extra money to earth sciences and improved the success rates for research applications.

Covering one-eighth of the globe and hiding much of its minerals, the Australian continent is fertile ground for geoscientists exploring the world beneath the surface.

It's harder to explore for minerals in Australia than many other countries, but in reaching them the country will be a laboratory for the rest of the world looking to find more elusive resources, Dr McFadden said.