Fossil leaves may reveal climate in last era of dinosaurs

The reason scientists look back in the past is to understand what's coming in the future,” said Kevin Anchukaitis, a climate researcher at the University of Arizona. We want to understand how the planet has responded in the past to large-scale changes in climate — how ecosystems changed, how ocean chemistry and sea levels changed, how forests worked. Of particular interest to scientists are “ hothouse ” periods when they believe carbon levels and temperatures were significantly higher than today.