Spotlight Scholar

Big-Picture Climatology

Looking to the distant past to predict Earth’s future climate
  • Geoscientist Robert DeConto conducting climate change research in Antarctica

DeConto’s latest submission to Nature challenges the current theory of a global super-warming event 55 million years ago.

When it comes to climate change, Geoscientist Robert DeConto sees the big picture. An international expert in global-climate modeling, he’s working to better predict our future climate by challenging popular theories of why the earth warmed or cooled millions of years ago.

One of a small group of climate scientists whose research spans the past, present, and future of climate change, DeConto is highly sought after by both the data-collection and climate-modeling communities. “I bridge the gap,” he says. “I travel with the field scientists who collect climate data and then use it to create detailed models to help predict future climate.”

Thanks to his big-picture perspective, DeConto has been recruited to take part in one of the largest-ever climate research projects, the Antarctic Geological Drilling (ANDRILL) program. This $30 million international geological paleoclimate research initiative is one of the first of its size to match modeling experts with field experts to study global change. It includes representatives from five nations and five American research universities, including UMass Amherst.

DeConto was in part selected for the project for his pioneering work on polar-climate and polar-region modeling done with colleague Dave Pollard of Penn State. Their landmark 2003 article in the journal Nature described their use of models to successfully simulate one of the most important climate changes in our planet’s history: the rapid formation of Antarctic ice sheets 34 million years ago. DeConto and Pollard challenged conventional scientific dogma by theorizing that the decrease in temperature and the buildup of ice sheets on Antarctica were due not to plate tectonics isolating the continent and creating cold ocean currents around the Southern pole, but rather to a precipitous drop in carbon dioxide levels. This research demonstrated a fundamental link between greenhouse gasses and ice-sheet buildup or melting.

“Rob’s Nature article is one of the most innovative and important modeling papers in pre-Pleistocene climate that has been published in 20 years,” says Mark Leckie, who heads the UMass Amherst Geosciences Department. In fact, the ice-sheet image DeConto and Pollard created for the article has become iconic, with governmental and scientific organizations regularly using it as a cover image for climate-change reports. Since the article’s publication DeConto and others have been trying to reconstruct past greenhouse gas changes and simulate their climatic consequences using sophisticated computer models.

DeConto’s latest submission to Nature challenges the current theory of a global super-warming event 55 million years ago. “Carbon dioxide and global temperatures rose very quickly during this time, comparable to the rate of change happening today,” he says. Popular theory attributes that rise to large amounts of methane gas being released by ocean-floor sediment, but DeConto believes the super-warming event was caused by carbon released on land, not at sea.

“The Antarctic continent would have been rich in permafrost 55 million years ago; permafrost contains peat, and peat stores a lot of carbon,” says DeConto, whose modeling suggests that as the permafrost thawed it released massive amounts of carbon into the atmosphere, causing extreme warming and ocean acidification. “We can see this beginning to happen today, in areas near the North Pole,” says DeConto.

What’s next for Robert DeConto? In 2010 he was one of 12 scientists worldwide chosen to develop a science plan for the new $2 billion Integrated Ocean Drilling Program. Over a 10-month period this panel of distinguished scientists developed a 100-page strategic document outlining key objectives and an operational plan for scientific ocean drilling from 2013 to 2023. As part of that plan, DeConto will focus on investigating and modeling the impact future climate change will have on sea level—a topic near and dear to all who reside in coastal areas. By comparing ocean-sediment cores with computer models of the world’s ice sheets and glaciers, DeConto hopes to “model the environmental impacts that sea-level rise will have on Earth’s environment and its people.”

Karen J. Hayes '85