Scientists studying leaves from a 23-million-year-old forest have for the first time linked high levels of atmospheric carbon dioxide with increased plant growth, and the hot climate of the time. The finding adds to the understanding of how rising CO2 heats the earth, and how the dynamics of plant life could shift within decades, when CO2 levels may closely mirror those of the distant past.
Scientists retrieved the leaves from a unique onetime New Zealand lake bed that holds the remains of plants, fish, spiders, beetle, flies, fungi and other living things from a warm period known as the early Miocene. Scientists have long postulated that CO2 was high then, and that some plants could harvest it more efficiently for photosynthesis. This is the first study to show that those things actually happened in tandem. The findings were published this week in the journal Climate of the Past.
“The amazing thing is that these leaves are basically mummified, so we have their original chemical compositions, and can see all their fine features under a microscope,” said lead author Tammo Reichgelt, an adjunct scientist at Columbia University’s Lamont-Doherty Earth Observatory and assistant professor of geosciences at the University of Connecticut. “Evidence has been building that CO2 was high then, but there have been paradoxes.”
Read more at Earth Institute at Columbia University
Image: Paleobotanists prospecting New Zealand's Foulden Maar for fossils, 2013. (Credit: William D'Andrea/Lamont-Doherty Earth Observatory)