Climate skeptics challenge the link between rising carbon dioxide levels and temperature. Yet, a look back in deep time shows temperature and carbon dioxide rising and falling in synch in a long-term relationship that's outlasted many a mountain, according to Lenart. An award-winning journalist and science writer who holds a Ph.D. in natural resources and global change, Lenart synthesizes research about the past 100 million years to consider how our planet responds to different climates, past and present.