Reconstructing Ancient Climate


Paleoclimatologist Al Wanamaker is measuring and sorting clam shells in northern Norway, and the clam shells are speaking to him. They’re telling him about weather patterns that have occurred here over the last 2,000 years.

Through his work with clam shells in Norway and similar research in Iceland and Maine, Wanamaker, an assistant professor of geological and atmospheric sciences at Iowa State, hopes to understand and reconstruct climate from the past in order to project it forward.

“You’ve heard of measuring the age of a tree by counting its rings; we use long-lived clam shells because they have bands like trees. They have a unique barcode of growth records,” he explains.

Wanamaker and European colleagues reconstructed over a millennium of climate change based on Arctica islandica clam shells collected off Iceland’s northern coast.

Twice Wanamaker has travelled to the northern coast of Norway. During last summer’s expedition the research team was accompanied by a Discover magazine photojournalist, Randall Hyman.

Hyman posted field notes online during the experience. One day, Hyman observed the research team as it stumbled upon thousands of Arctica islandica shells heaved ashore by an overnight storm. He posted this in his online field notes:

‘This is heaven!’ Wanamaker exclaimed, kneeling on the white-sand beach and examining the goods. ‘This is unbelievable, seeing them in such heaps and piles.’ Assistants and scientists sifted through the piles and marveled at their good luck.”

Most shells are not so easy to come by. Wanamaker and the research team, including students, spent most days dredging the deep water of the cold north Atlantic for clam shells – and the elusive live clams.

Early in his career, Wanamaker was a high school science teacher. Then he went to a workshop on climate change and “got hooked.” He went back to school for a graduate degree. “It was a one-way ticket to where I am now,” he says.

Paleoclimate research results, like the field itself, take a long time to sort out. Wanamaker’s current project has been funded for three years, but there’s no guarantee he’ll have all the results by then. Still, he’s eager to try.

“It may take my entire career to figure this out.”


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