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

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.

Extreme weather events continue to grow more frequent and intense in rich and poor countries alike, not only devastating lives, but also infrastructure, institutions, and budgets - an unholy brew which can create dangerous security vacuums.

The clear and present danger of climate change means we cannot burn our way to prosperity. We already rely too heavily on fossil fuels. We need to find a new, sustainable path to the future we want. We need a clean industrial revolution.

Countries with more gender equality have better economic growth. Companies with more women leaders perform better. Peace agreements that include women are more durable. Parliaments with more women enact more legislation on key social issues such as health, education, anti-discrimination and child support. The evidence is clear: equality for women means progress for all.

Men must teach each other that real men do not violate or oppress women - and that a woman's place is not just in the home or the field, but in schools and offices and boardrooms.

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.