Sir Peter Gluckman, Former New Zealand Chief Scientific Advisor, presented the fourth Wolfson College Lecture in this series on modern diplomacy. The lecture was introduced by Sir Tim Hitchens. Science diplomacy has become much more than international science collaboration; it is primarily the intentional application of science (both natural and social) or scientific expertise in furtherance of diplomatic objectives. Structures for effective science diplomacies are often lacking; emerging issues drive a new emphasis on the global commons and thus the need for science diplomacy. The paradox, however, is that while globalization is being impaired, the need to address issues of the global commons is rising. Science can assist with most policy challenges, and in this lecture Sir Peter Gluckman explains that this is true also for much of diplomacy. Creative Commons Attribution-Non-Commercial-Share Alike 2.0 UK: England & Wales; http://creativecommons.org/licenses/by-nc-sa/2.0/uk/