New Horizons in Science

At the 1988 briefing in Boulder, “Future Climate/Future Life” served as the rubric for tandem presentations by Ralph Cicerone and the late Stephen Schneider, both at the time senior atmospheric scientists at the National Center for Atmospheric Research. Among the issues under scrutiny then:  How fast – and how far – would temperatures rise in response to the rising levels of greenhouse gases? What were the sources and sinks of the various trace gases? What more did we need to know to better refine our assessment of Earth’s fate?   Climate science has come a long way since.  In 2001, a landmark National Research Council study, chaired by Cicerone and released on the eve of the Kyoto climate talks, asserted that “Greenhouse gases are accumulating in the Earth’s atmosphere as a result of human activities…” This year, as chair of the NRC, he oversaw the Academy’s America’s Climate Choices, a series of reviews of the state of climate science, options for limiting its magnitude and possible adaptive regional and global strategies. In his return visit, Cicerone reflects on the journey that has brought us to where we are now in our understanding of climate change, and offers, from his unique perspective, a best-guess look at what looms.