Recent developments at the University of Western Ontario have unearthed a new way to dig into the dirt of history and track the earth’s climate all the way back through the last three ice ages and the interglacial periods.

Zhenzhen Huang, an isotope chemist at the university, has pioneered a method that uses phytoliths, or plant stones, from fallen and decomposed vegetation to provide data regarding the conditions of the earth’s climate as far back as 300,000 years ago. phytoliths are tiny, unique crystals of silica that form in plants as they grow. They are long lasting and have been previously harvested from fossils and used as clues to better explain the eating patterns of dinosaurs.

The experiment performed by Huang involved growing a variety of marsh plants in climate-controlled containers over a period of eight months at temperatures of 15, 20, 25 and 30 degrees Celsius. He found that with each temperature condition, plants grew silica with unique isotope ratios. The isotope ratios were plotted and displayed a gradient scale that matched the scale of the temperatures. On average, plants grown at higher temperatures grew silica containing higher ratios of oxygen-18 to oxygen-16 isotopes than plants grown at lower temperatures. Therefore, by reading the ratio of isotopes in fossilized phytoliths, scientists may know the approximate temperature at which the plant grew. This information, coupled with carbon dating of the phytoliths, will provide a map of the various climates in which the plants grew throughout history.

The great Italian author Machiavelli once wrote, “Whoever wishes to foresee the future must consult the past; for human events ever resemble those of preceding times.” This new method will allow scientists to map the earth’s climate changes for a significant chunk of history that was previously a mere set of postulations. The data, in turn, will enable scientists to make more informed predictions on how climate change will affect earth’s life forms in the future.

Considering the large number of alarms that have been sounding off these days about global warming and other major concerns over climate control; this information can be a boon to climatologists. As they say: only by understanding our past, can we better prepare ourselves for the future.

Discussion question: How might this method provide information beyond simple climate data? How might this information change the current climate debate?

Article Link: http://sciencenews.org/view/generic/id/44218/title/Phytoliths_as_climate_clues

Scientific study reported on May 26 at an American Geophysical Union meeting

** The image for today’s story and additional pictures of phytoliths can be found at the Smithsonian Institute website: http://www.mnh.si.edu/highlight/phytoliths/index.html