23-Million-Year-Old Fossilized Leaves Offer New Insight Into Global Warming

UPI reports:
The links between rising carbon dioxide levels, global warming and greening trends have been confirmed by fossilized leaves from a 23 million-year-old forest… Scientists previously postulated that ancient increases in atmospheric CO2 during the early Miocene allowed plants to perform photosynthesis more efficiently. But the latest research, published Thursday in the journal Climate of the Past, is the first to confirm the link between CO2 and greening in the fossil record… Lab experiments have shown increases in CO2 can boost photosynthesis, and recent satellite surveys suggest rising CO2 levels are responsible for greening patterns across the planet, including Arctic and drylands ecosystems. The latest research suggests that greening trends are likely to continue as CO2 levels approach those recorded during ancient period of warming… According to the new study, increases in photosynthesis rates won’t be able to keep up with current rates of human-caused carbon emissions. In addition, previous studies suggest increases in rates of photosynthesis can prevent staple crops from absorbing calcium, iron, zinc and other minerals important for human health…. By comparing the fossilized leaf structures, including microscopic veins, stomata and pores, to those of modern leaves, researchers designed a model to more accurately predict CO2 levels… “It all fits together, it all makes sense,” said study co-author William D’Andrea, a paleoclimate scientist at Lamont-Doherty. “This should give us more confidence about how temperatures will change with CO2 levels.”