Saving our planet requires you to be ambitious in what you aim, and, equally, in how hard you work to reach your goal.

Nuclear terrorism is one of the most serious threats of our time. Even one such attack could inflict mass casualties and create immense suffering and unwanted change in the world forever. This prospect should compel all of us to act to prevent such a catastrophe.

Given the nature and magnitude of the challenge, national action alone is insufficient. No nation can address this challenge on its own. No region can insulate itself from these climate changes. That is why we need to confront climate change within a global framework, one that guarantees the highest level of international cooperation.

There can be no solution to the challenge of climate change that is not global. But if we can come together in partnership, we can transform today's challenge into tomorrow's opportunity - an opportunity for green growth and sustainable prosperity... we also need a strong bottom-up push from academics and opinion-shapers such as you. Universities such as yours are founts of ideas and innovation. They are furnaces of innovation and entrepreneurship. So, send forth this word.

On this International Day for the Abolition of Slavery let us reaffirm the inherent dignity of all men, women and children. And let us redouble our efforts to build societies in which slavery truly is a term for the history books.

The current model is global suicide. We need a revolution. Revolutionary thinking. Revolutionary action. Natural resources are becoming more and more scarce.

Saving our planet requires you to be ambitious in what you aim, and, equally, in how hard you work to reach your goal.