Prof. Dan Yakir of the Department of Environmental Sciences and Energy Research in the Faculty of Chemistry found the paper in library collections of old books and newspapers contains a record of atmospheric conditions at the time the trees that went into making the paper were growing. Yakir says he has traced the effects of atmospheric pollution from burning fossil fuel going back to the beginnings of the Industrial Revolution.
Scientists generally reconstruct the record of past climate change from such sources as ice cores or tree rings. But a reliable tree ring history, says Yakir, requires an analysis of quite a few trees. “Rather than going to forests all over the world to sample trees,” says Yakir, “we went to the local library.”
In the Weizmann library’s archives, Yakir found issues of the scientific journals Science, Nature and the Journal of the Royal Chemical Society going back over 100 years to the late 19th century.
Small samples from the margins of successive volumes were analyzed for the proportion of two carbon isotopes that showed levels of CO2 added to the atmosphere from burning fossil fuel.
The levels in the paper were a good match for existing atmospheric records and even revealed some local phenomena, including differences between American and European records, Yakir says.
In addition to alerting climate scientists to a very well organized, untapped source of global change records, says Yakir, the technique could be used to authenticate antique paper samples.