The Rock Whisperer: UNCW Professor Principal Investigator on Major Climate Change Research Shares $4.25 Million NSF Grant

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Thursday, May 03, 2012

The Earth is warming. Determining what this will mean for future generations is one of the greatest challenges in modern science, and UNCW Environmental Science Studies Professor Paul Hearty has been tapped as one of a world-class team of scientists working to provide answers to this question.

Hearty is one of five principal investigators on a grant to build a comprehensive model of past climate change by integrating elements of the world's crust, oceans, atmosphere and ice sheets, using fossil and geological data from an ancient warming period 3 million years ago. The National Science Foundation has funded the five-year study for $4.25 million, a rare achievement in an age when basic research budgets have been drastically cut and many studies are funded.

Approximately 3 million years ago, the Earth was warmer. Global average temperatures were 2-3 Celsius (3.6F to 5.4F) greater than today. Known as the Mid-Pliocene Climatic Optimum (PLIOMAX), this interval has received renewed attention by researchers because its temperatures and composition of the atmosphere are similar to those predicted by global climate change models of the coming century.

"We have to go back 3 million years to find CO2 levels of 400 ppm.  Our atmosphere, now at about 393 ppm, will easily reach 400 ppm by the end of this decade." said Hearty.

Over the next five years of the grant, the PLIOMAX team will tackle three major problems in climate science. In the first phase, they intend to use fossil and geological data collected at sites across the world to build a greatly improved database of sea levels and thus ice sheet behavior during the Pliocene.

"Geology has to drive this process. Geology provides first-hand information about the position and movements of sea level," said Hearty.

In a subsequent phase of the project, these data will feed into a series of experiments that will provide estimates of the global sea level under a variety of climate change scenarios.  From this work, the team also intends to build a high-resolution comprehensive model of the world's atmosphere-ocean-ice sheet/shelf systems. The ultimate goal of the project is to better forecast the potential behavior of sea-level and ice sheets in a warmer world.

For climate researchers, the Mid-Pliocene represents the last great warm period in Earth's history. As the era's climate roughly resembles the late 21st century projected by the UN's Intergovernmental Panel on Climate Change, the Pliocene has drawn extensive academic interest in recent years. Agencies such as the U.S. Geological Service and the British Geological Survey have begun major efforts to construct data models from this period.

While there is general agreement about the temperatures of the Pliocene,, controversy exists about the extent to which these warmer temperatures and higher carbon dioxide levels affected global sea levels. Researchers agree that sea levels were higher during the Mid-Pliocene, but the magnitude of the rise has been hotly debated. Researchers' estimates have ranged from 10 meters (32 ft.) to around 40 m. (131 ft.) higher than today. Higher sea levels are directly tied to melting of the world's polar ice sheets such as Greenland and Antarctica.

Hearty is hesitant to make predictions based on the past. He acknowledges the complexities of predicting the future through studying geological and modeling data. Climate science deals with a massively complex system, and the variables that led to sea level rise 3 million years ago included more than simple temperature and CO2 relationships.

Even so, the most conservative estimates of sea level rise during the period would, if repeated in a warming future, dramatically change the shape of the world's coastlines. On a geological scale, measured in millions of years, the ocean has risen and fallen many times due to climate change. Hearty said important geological evidence of this can be found throughout Southeastern North Carolina, which once was submerged beneath the ocean.

Hearty will serve as one of the principal investigators on the grant, a prestigious spot on a project featuring an all-star team of researchers from the top universities in the United States. The project's leader, Professor Maureen Raymo of Columbia University, is widely recognized as a global leader in the field of paleoclimatology and paleoceanography. She and the other members of the team have, working jointly in various combinations, have published widely on climate change in the Pliocene.

Hearty has worked and published with the team for years, including leading a field expedition in Australia from which findings provided the rationale for the larger study. Raymo praises Hearty's fieldwork skills, calling him one of the best in the world at interpreting sea level changes from the rocks and analyzing fossil data.

"Paul is an amazing field geologist with decades of experience looking at the coastal record of sea level change.   I call him 'The Rock Whisperer,'" said Raymo.

The grant's other principal investigators - geoscientist Rob DeConto from the University of Massachusetts-Amherst, physicist Jerry Mitrovica of Harvard and earth scientist David Pollard of Penn State - all have world-class reputations in their fields. In recommending the grant for full funding, the reviewers at the National Science Foundation cited the vast expertise of the team as a major factor in the decision.

Hearty's role will be to lead field expeditions collecting the fossil and geological evidence that will make up the raw data to be used by the ice and crustal modelers. One of the chief hurdles in accurately modeling the past and future behavior of global climate has been a lack of sea-level data.

The PLIOMAX team has already provided solutions to some of the period's greater mysteries. In examining past glaciations and interglacials, they determined that not only will the levels of the oceans rise when the ice melts, but the earth itself will actually slowly respond when relieved of the pressure of millions of tons of ice. The deformation of the earth combined with the rising waters has led to some of the large discrepancies in findings of past studies.

"You can load kilometers of ice on a continent, and as the ice disappears, the continent rebounds hundreds of meters," said Hearty.

Resolving this controversy is of more than academic interest. The world's governments will need accurate projections to plan for a world of rising seas. In recommending that the study receive full funding, the NSF's review panel praised the research's strong societal relevance.

To collect this data, Hearty and other members of the PLIOMAX team gather samples and precise measurements from regions that share common traits: coastal regions located in tectonically stable areas far from tectonic plate boundaries. The team has already gathered data in Australia, will travel to South Africa this year and plan with planned research expeditions to India, Madagascar and throughout the Southeastern United States..

Much of this research would have been impossible little more than a decade ago, because of the vast amounts of manpower and time that it would have taken to collect the data. With tools like differential GPS units that are topographically accurate within a few centimeters and Google Earth images, the team can accomplish in a single day research that would have taken researchers much longer in past years.

"Armed with a laptop and a GPS on your dashboard in real time you can track yourself and potential outcrops on a digital geologic map" said Hearty.

Hearty trusts the final results of the study will prove valuable in the future.. By understanding the response of nature to past global changes, he hopes that future generations will be better prepared to deal with the anticipated effects of climate and sea-level changes.

"None of us think that in our human lifetime or even over several generations, sea level is going to rise 25 meters," said Hearty.

But it will rise. It has in the past, and it will again in the future. Hearty says that addressing these changes will be one of the major challenges of the world's future leaders.

"We're tinkering with a natural machine we don't understand," said Hearty.