On June 30, Ralph Cicerone, the 21st President of the National Academy of Sciences, ends his second and final term. Throughout his tenure, the Academy has continued its tradition of providing expert, independent scientific advice to the nation. Cicerone's leadership has ensured that the Academy's work remains indispensable in helping find solutions to some of the nation's most pressing science and policy questions.

His significant milestones and accomplishments include the restoration and renovation of the historic National Academy of Sciences building on the Mall, the creation of a $500 million Gulf Research Program following the Deepwater Horizon disaster, two visits to NAS by President Obama, and a number of influential studies that helped to define the causes, extent, and effects of global climate change.

Cicerone is an atmospheric scientist whose research in atmospheric chemistry, climate, and energy has placed him at the forefront in shaping science and environmental policy, both nationally and internationally. In 2001, he led a key National Academy of Sciences study about climate change requested by President George W. Bush. Ten years later, the Academies produced America's Climate Choices, a comprehensive set of reports that called for action on reducing greenhouse gas emissions while identifying strategies to help the nation and world adapt to a changing climate. Under Cicerone's guidance, the NAS and the Royal Society -- the science academy of the U.K. -- teamed up in 2014 to produce Climate Change: Evidence and Causes, a readable publication written for policymakers, educators, and members of the public.

Engaging the general public in science has been a major priority for Cicerone, who spearheaded the creation of the NAS's Science & Entertainment Exchange. This unique program connects entertainment industry professionals in Hollywood with top scientists and engineers to assist in the portrayal of science in film and TV. The results can be seen on many of today's popular TV shows and movies. He also worked on developing the widely cited 2008 book Science, Evolution, and Creationism, which lays out the scientific evidence supporting evolution in a clear way for many audiences.

Helping scientists probe and understand the promise and potential problems posed by powerful emerging technologies like gene editing has also been a priority for Cicerone. In 2015, NAS and the National Academy of Medicine jointly convened an international summit to explore the many issues raised by the arrival of a new class of genetic tools (such as CRISPR/Cas 9) for potential use in transforming humans, plants, and animals.

Within the NAS, Cicerone's initiatives have demonstrated his commitment to maintaining the institution's relevance in a rapidly changing world -- while still upholding its values of independence and excellence, which have sustained the NAS for more than 150 years. Under his leadership, NAS has focused on increasing the number of women, minorities, and younger scientists elected to its membership. For NAS members and the larger scientific community, Cicerone has also taken the lead in speaking out publicly for the need to maintain integrity and transparency in research.

In his frequent visits and consultations with members of Congress, key Hill staffers, and federal agency heads, he has spoken out on behalf of science and science education. In congressional hearings, he testified in support of implementing recommendations from the Academies' landmark 2005 report Rising Above the Gathering Storm through the America Competes Act.

As President Cicerone and his wife Carol leave us, their legacy will include a new endowment designed to help continue the work of the Academies into the future. The Ralph J. and Carol M. Cicerone Endowment for NAS Missions will be used to develop and support programs and policy studies on newly emerging topics before they have been recognized by the government and others as major challenges to the nation. A $10 million challenge grant from the Simons Foundation will launch a campaign to raise matching funds for the endowment.