EXCLUSIVE: The shakeup at the National Geographic Society continues. I’ve learned that this afternoon National Geographic Society president Tim Kelly announced internally that he will leave the company at the end of the year after three decades. His departure comes on the heels of the July exit of Maryanne Culpepper, president of National Geographic Television, the studio/documentary arm of the National Geographic Society.

Kelly joined National Geographic in 1982 and rose through the ranks to president, a title he’s held since January 2011. I hear there is no plan for a direct replacement, with National Geographic Society chairman and CEO John Fahey slated to discuss the transition in a company-wide staff meeting tomorrow. I hear the departure of Kelly is part of Fahey’s plans to overhaul the 124-year-old non-profit scientific and educational institution, bringing it faster into the digital age.

In his memo to the staff today, obtained by Deadline, Fahey listed Kelly’s contributions. “He has played a key role in the evolution of our operations from a primarily English-only, print-based organization to a multi-media global force,” he said. “Tim also conceived and led the development of the National Geographic Channels, which launched originally in Europe and Australia in 1997, and then rapidly expanded around the globe, premiering in the United States in 2001. Those successes have been instrumental in fueling the growth of the Society’s exploration, conservation, and educational initiatives.”

In a company email, Kelly said that he will work with Fahey “to ensure a smooth transition.” “Geographic has been my obsession and addiction all these years,” he said. “I loved every minute and will cherish every memory, from being part of Bob Ballard’s finding the Titanic, to seeing next month’s National Geographic Magazine cover story on ‘Blood Ivory’.” Kelly indicated that he doesn’t have another gig lined up. “My new plans are uncertain, and I am happy about that,” he said. “It’s time for family, some whimsy, travel and contemplation before my next big adventure.”