Purdue climate scientist sees clues to tomorrow in Earth's past

WEST LAFAYETTE -- Matthew Huber spends hours each week at a Starbucks on Purdue University's campus, hunched over a laptop with a cup of java as he ponders the ancient calamities that repeatedly altered Earth's climate.\nWhile students chat nearby, he might run a simulation of the dinosaur-slaying global winter believed to have followed an asteroid impact 65 million years ago.\nOr, he might focus on trying to explain why the Earth, after eons as a tropical world, abruptly cooled about 34 million years ago to a milder place.\n"That's the kind of thing I do -- think about the end of the world, the beginning of the world," Huber jokes during a coffee break in Purdue's Student Union Building.\nHuber is an assistant professor of earth and atmospheric sciences at Purdue. At 34, he is a relatively young figure in the field of ancient climate research, but he's making his mark with his computer models of what climate researchers call "deep time events."\nHe co-authored two research papers that have won international attention in the last year. One proposed that when an asteroid or comet walloped the Earth, it kicked so much dust into the atmosphere that it blotted out the sun for up to five years.\nBefore the skies cleared, the dinosaurs starved or succumbed to the cold.\nHuber's computer models arise from the same simulations of ocean currents and weather patterns other scientists put to the question of global warming.\nBut beyond those raw numbers and formulas lies inspiration, which Huber says is crucial for him to do his work.\nAs a graduate student studying ancient climate modeling at the University of California at Santa Cruz, he frequently wandered into nearby redwood forests to get a sense of what the world was liked in the Eocene, a tropical period 35 million to 55 million years ago.\n"If you really want to understand what it was like 50 million years ago, you have to try to immerse yourself in it, to imagine that you are living in that world," he says.\nIn Indiana, Huber does some of his work while walking or in unorthodox settings like coffee shops, which he says are more inspiring than his office's "square, cinderblock walls."\nHe has been fascinated by the mysterious events of past ages since his childhood, part of which he spent in the idyllic setting of a Hawaiian beach. He and his parents, who were pursuing the hippie dream, lived for a time in the early 1970s in a tent on the edge of the Pacific Ocean.\nHuber recalls spending his days shoeless and shirtless, searching for shells dredged up by the Pacific's powerful currents; at night, the surf lulled him to sleep.\nIt's little surprise, then, that a boy who was snorkeling by the time he was 4 grew up fascinated by the ocean, weather and the planet's geology.\nBette L. Otto-Bliesner, a climate researcher at the National Center for Atmospheric Research in Boulder, Colo., said Huber takes a holistic approach to explaining ancient events.\n"He uses his knowledge of the ocean, the atmosphere and the geologic record to get a better understanding of these deep time climate periods," she said. "He's made important contributions to understanding how ocean circulation changed -- and why it changed."\nIn a paper published in December in the journal Paleoceanography, Huber and several international co-authors proposed a new explanation for why Antarctica developed a vast ice sheet about 34 million years ago after being relatively ice-free until then.\nThe prevailing theory had been that a shift from warm to cold ocean currents spurred the ice sheet's formation.\nBut based on fossil evidence and Huber's computer modeling, they concluded that the ice sheet formed relatively quickly, within tens of thousands of years, because a sharp drop in levels of carbon dioxide -- a greenhouse gas -- cooled the Earth.\nHuber said those findings suggest the Antarctic ice sheet could melt significantly in the next 200 years, pushing up sea levels, if carbon dioxide levels rise as rapidly as is predicted.\n"If you look at the estimated range of carbon dioxide concentrations that once existed, that's the range that we're going to be going to in the next couple of hundred years, which is very disturbing," he said.\nIn another paper published in June in the journal Geology, Huber delved into the global winter blamed for the dinosaurs' demise.\nHis computer model explains the existence of fossilized cold water-loving plankton and other organisms found in northwestern Tunisia. Those fossils were found by Huber's co-authors in sediment laid down some 2,000 years after the cosmic impact in Mediterranean waters that should have been too warm for the plankton.\nHuber's model suggests that particles kicked up by the impact darkened Earth's skies for up to five years, freezing the dinosaur's tropical world. The oceans stayed cold for thousands of years, and upwellings of those waters in areas like those near present-day Tunisia allowed the cold-water plankton to thrive.\nDiscover magazine ranked the paper's findings one of the top 100 scientific discoveries of 2004, calling it "the first convincing evidence" for the global winter scenario.\nOtto-Bliesner, who shares the chairmanship, said clues to past climate changes are becoming increasingly relevant to understanding global warming.\n"If we only look at the recent past, there are changes but not to degree that we see in the very distant past," she said. "We're finding that we can use data from past climate change to understand what tomorrow might bring"