For my generation, coming of age at the height of the Cold War, fear of nuclear winter seemed the leading existential threat on the horizon. But the danger posed by war to all humanity-and to our planet-is at least matched by climate change.

Climate change, demographics, water, food, energy, global health, women's empowerment - these issues are all intertwined. We cannot look at one strand in isolation. Instead, we must examine how these strands are woven together.

The taking of life is too absolute, too irreversible, for one human being to inflict on another, even when backed by legal process. Where the death penalty persists, conditions for those awaiting execution are often horrifying, leading to aggravated suffering.

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.

I believe in a world of justice and human rights for all. A world where girls can grow up free of fear of abuse. A world where women are treated with the respect and dignity that is their right. A world where poverty is not acceptable. My dear young friends, you can make this your world.

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.

For my generation, coming of age at the height of the Cold War, fear of nuclear winter seemed the leading existential threat on the horizon. But the danger posed by war to all humanity-and to our planet-is at least matched by climate change.