Miami geologist mentioned in National Geographic

"World Without Ice," a feature story in the Oct. 2011 issue of National Geographic, mentions the research of Ellen Currano, assistant professor of geology and environmental earth sciences at Miami University.

Scientists have observed that as the Paloecene epoch gave way to the Eocene, around 56 million years ago, “there was a massive and sudden release of carbon... (that) brought on drought, floods, insect plagues, and a few extinctions,” according to the article.

The effects of the Paleocene-Eocene Thermal Maximum, or PETM — could be a model for global climate change if humans keep burning fossil fuels.

Scott Wing, paleobotanist at the Smithsonian Museum of Natural History, and Currano examined thousands of fossil leaves from the Bighorn Basin, of which “nearly six in ten have holes or curving channels chewed into them by insects,” according to the article. “Maybe the heat had revved up the bug’s metabolism, causing them to eat more and reproduce more. Or maybe the extra carbon dioxide had directly affected the plants ... making their leaves less nutritious.”

Currano’s research, recently published with co-authors in the Nov. 2010 issue of Ecological Monographs, “Fossil insect folivory tracks paleotemperature for six million years shows that the long-term response of plants and insect herbivores to temperature change can be interpreted by analyzing insect herbivore damage on fossil plant leaves, as plants and insects have coevolved for millions of years.

Currano and her co-authors examined more than 9,000 fossilized leaves from nine sites in the Bighorn Basin that had fossils dating back 52.7 to 59 million years ago. They identified 107 plant species and recorded the presence or absence of 71 insect-feeding damage types. They found that the rise in global temperature led to an increase in insect populations and diversity, suggesting that climate change affects coevolutionary links between plants and insect herbivores.

“The PETM was a tremendous perturbation to Earth, climate and life. If we continue to burn fossil fuels at our current rate, we will have carbon dioxide levels comparable to the PETM,” Currano explained. “My colleagues and I study the PETM because we believe that the past is the key to the future.”