Professor Gregory Webb on coral reefs, climate, and carrying Dorothy Hill’s torch
When Professor Gregory Webb first arrived at The University of Queensland in 1984, it was with the dream of studying under the shadow of a scientific giant. Now, more than 40 years later, he is stepping down from the Dorothy Hill Chair in Geological Sciences – an academic role named in honour of the very person who first drew him to UQ: Australia’s trailblazing geologist and palaeontologist, Professor Dorothy Hill.
“I came here because of Dorothy,” Webb says. “She was the world’s authority on fossil corals. I was a new PhD student, and I wanted to learn from the best – Dorothy and her student, John Jell.”
A lifelong fascination with ancient life
Webb’s passion for palaeontology was sparked in childhood, thanks to the unlikely influence of his parents’ old university textbooks.
“One of the first books I ever read, besides See Spot Run, was Principles of Invertebrate Paleontology. The other was Animals Without Backbones,” he says. “They were filled with pictures of trilobites, crabs, strange extinct creatures. I fell in love with them.”
It wasn’t long before that curiosity became a calling. Today, Webb is a globally recognised expert on fossil and modern coral reefs, specialising in the study of how organisms make rock – a process that tells us far more than most people realise.
“I work on how organisms build limestone – reefs, really. That rock is a record of ancient environments. We can analyse the geochemistry of corals to find out what the water temperature was 5,000 years ago. We can see how dirty the water was, how much rain there was, even what seasons were like.”
Microbial mysteries and modern reefs
Webb’s work has led him into the world of microbialites – structures built by microbial communities that helped form ancient reefs and are still building modern ones.
“When I came here, I thought the microbialites that built the reefs 300 million years ago were long gone,” he recalls. “But then I saw blocks dredged from Heron Reef and thought – holy cow, this is the same stuff. It’s still here!”
This kind of discovery changes the way we view reef evolution, and it also hints at continuity between past and present, something Webb finds deeply meaningful.
“The reefs we’re studying today might actually resemble ancient ones more than we realised,” he says. “That kind of insight – Dorothy would have loved that.”
Reefs as climate archives
Much of Webb’s work connects the dots between palaeontology, geochemistry, and climate science. Coral skeletons aren’t just remnants of life – they’re precise climate recorders.
“People often think climate science is all computer modelling and weather forecasts,” he says. “But those models are built on geological data – on the oxygen isotopes in coral, for example.”
Through chemical analysis of reef limestone, Webb and his students can track sea level changes, temperature variations, rainfall shifts, and even major climate phases like the El Niño Southern Oscillation (ENSO).
“We showed that the southern Great Barrier Reef had much more rainfall and runoff until about 5,000 years ago,” he says. “That’s when ENSO set in, more or less in the pattern we see today.”
Understanding this past is essential to preparing for the future.
“We need to know what's natural and what's not,” Webb says. “Only with that baseline can we isolate the human impact.”
The power of empirical evidence
Webb is passionate about the role of field-based, empirical science in building the datasets modern climate models rely on.
“AI and physics models are incredible, but they can only work with the data we give them,” he says. “If something happened in the past and we never recorded it, the models can’t account for it.”
He points to historical events like “meltwater pulses” – sudden rises in sea level as ice sheets melted – which were only identified through reef core data.
“The only reason we know those events happened is because we saw them in the rock,” he says. “You can't model what you don't know exists.”
That’s why the continuation of the Dorothy Hill Chair is so important, Webb says. It supports the long-term research necessary to gather this kind of information.
“This chair allows someone to dig deep into the record, literally and metaphorically,” he says. “It’s about understanding change over time, and the science it enables is essential – for reefs, for conservation, and for climate resilience.”
Passing on the legacy
While Webb has made his mark with publications and discoveries, he sees his most important contributions in his students.
“When I think about impact, I don’t think about journal articles,” he says. “I think about students. Maybe I was someone’s Shrock and Twenhofel – the person who sparked their curiosity.”
That academic lineage is something Webb takes seriously. From Dorothy Hill to John Jell to Webb, and now to his former students, like Associate Professor Gilbert Price, the legacy of mentorship continues.
“My students know they’re Dorothy’s academic great-grandchildren,” he says. “That matters. It connects us to a tradition of excellence.”
“Dorothy would be amazed”
As he reflects on his time in the Chair, Webb wonders what Dorothy Hill would make of the work being done now.
“She’d be flabbergasted by the geochemistry,” he says. “We can now say with precision what year something happened, what the temperature was, what was in the water. She’d be amazed.”
But more than anything, he believes she’d be proud that Australian science has found its voice.
“Before Dorothy, you had to publish in a British journal to be taken seriously. She changed that. She showed the world that world-class science could be done right here,” he says. “She did it without ego, without politics. Just through sheer excellence.”
“She sat in rooms full of powerful men in suits, and she never needed to raise her voice. Her work spoke for her.”
Looking forward
So what’s next for Webb?
“Oh, I’ll keep working. There’s still so much to learn,” he says. “We’re studying reef cores from Hawaii now – trying to fill gaps in the sea level record. The sky’s the limit.”
And for the Dorothy Hill Chair?
“I just hope the next person in this position will carry the same love for the work, and the same respect for the legacy,” Webb says. “This isn’t just about coral. It’s about understanding who we are on this planet – and how we fit into its story.”
It’s clear that Dorothy Hill’s spirit – of curiosity, humility, and scientific excellence – will continue to be recorded in the limestone of scientific history.
