FARMINGTON -- The University of Maine at Farmington on Thursday will present a series of talks featuring two internationally-known climate-change experts, as part of its ongoing series known as Common Ground.

The day's events, called "Climate Change -- Perspective, Surprises and Opportunities" are part of UMF's 2009 Climate Forum.

At noon, Dr. Paul Mayewski, the director and a professor at the Climate Change Institute at the University of Maine, will speak in Lincoln Auditorium in UMF Roberts Learning Center. The leader of the Greenland Ice Sheet Project and more than 50 other scientific expeditions to Antarctica, the Arctic, Tibet and other remote regions, he is also the author of "The Ice Chronicles -- The Quest to Understand Global Climate Change."

He will explain what climate is; why does it change and how fast it happens; the impact of humans on climate; how small a change in climate is important; and what needs to be done.

At 4 p.m., a talk on "Did Early Farming Prevent a New Ice Age? The Answer: Yes!" by Dr. William Ruddiman, professor emeritus at the University of Virginia, will be held in Lincoln Auditorium. He is a Doherty Senior Research Scientist at Lamont-Doherty Earth Observatory of Columbia University, and is the author of "Plows, Plagues, and Petroleum," and "Earth's Climate: Past and Future."

The events are free and open to the public.