Fossil leaves may reveal climate in last era of dinosaurs - and could be key to understanding global warming
- The ginkgo tree has been around for 200 million years, and its leaves change slightly depending on the carbon dioxide level in the atmosphere
- Scientists are comparing 100-million-year-old ginkgo leaf fossils to leaves from ginkgo trees grown today at various carbon dioxide levels
Richard Barclay opens a metal drawer in the archives of the Smithsonian Natural History Museum in Washington containing fossils that are nearly 100 million years old. Despite their age, the rocks aren’t fragile. The geologist and botanist handles them with casual ease, placing one in his palm for closer examination.
Embedded in the ancient rock is a triangular leaf with rounded upper lobes. This leaf fell off a tree around the time that T. rex and triceratops roamed prehistoric forests, but the plant is instantly recognisable.
“You can tell this is ginkgo, it’s a unique shape,” says Barclay. “It hasn’t changed much in many millions of years.” Native to China, the deciduous ginkgo is a prized ornamental tree in many parts of the world.
What’s also special about ginkgo trees is that their fossils often preserve actual plant material, not simply a leaf’s impression. And that thin sheet of organic matter may be key to understanding the ancient climate system – and the possible future of our warming planet.
But Barclay and his team first need to crack the plant’s code to read information contained in the ancient leaf.
