Kent Memorial Library and Housatonic Valley Association will co-sponsor a program about 500 million years of local natural history Sept. 9 at 2 p.m.

The program will take place at Kent Town Hall at 41 Kent Green Boulevard.

Artist and author Charles Raskob Robinson will lead the program, which will address the “Snowball Earth and Hothouse Earth,” wild fluctuations between periods of prolific species creation and Earth’s five mass extinctions when 75 percent or more of all species were killed off.

Scientists believe we’re entering the sixth mass extinction, the first one caused by humans.

Environmentalist Tim Abbott of HVA will follow with a presentation about HVA’s recent efforts to promote conservation by working with towns throughout Litchfield County and the tri-state Housatonic Valley watershed.

Abbott, who has a distinguished career in environmental conservation, joined the HVA Litchfield Hills Greenprint Program as director in 2008.

The Greenprint Program is a collaboration with Litchfield County communities and local and regional land trusts to create a conservation vision, and increase the rate and scale of land conservation in the region.

Earlier in his career, Abbott ran Greensleeves Environmental Services, an environmental consulting company, and was the Berkshire Taconic Landscape program director for The Nature Conservancy.

Prior to that he spent several years in Namibia, Africa, as a Fulbright Scholar and employee of The Forum for Integrated Resource Management working on grassroots institutional organizing and community building.

Robinson became fascinated with the history of this part of the planet when he did 35 plein air paintings of Litchfield’s Lake Waramaug over a two-year period during all times of day and seasons.

This led him to dig into the history of nature over the eons — especially the last 500 million years, during which time the lake was formed.

The resulting book, “Lake Waramaug Observed,” was published earlier this year.

He also wrote “The Naval War of 1812-1815: Foundation of America’s Maritime Might” and directed and produced a seven-part video documentary series in conjunction with the United States Navy, Marine Corps and Coast Guard and 60 museums in Europe, Canada and the United States, “The Naval War of 1812 Illustrated,” as part of the 1812 Bicentennial commemoration.

To register for the event, email or call 860- 927-3761.