FALMOUTH, Mass. (AP) — President Barack Obama's top science adviser has rejoined the climate science organization he led before his White House service.

John Holdren on Friday rejoined the Massachusetts-based Woods Hole Research Center as a senior adviser to its president. Holdren was himself president of the organization from 2005 to 2009 before joining Obama's team.

The Woods Hole Research Center is a top-rated independent climate-change think tank.

Holdren joined the Obama administration in 2009. He became the longest serving presidential science adviser.

Holdren has also been re-appointed to his position as a professor of environmental science and policy at the Harvard Kennedy School and Harvard's department of earth and planetary sciences.