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.

Three decades into this crisis, let us set our sights on achieving the "three zeros" zero new HIV infections, zero discrimination and zero AIDS-related deaths.

I spend most of my time in South Korea but at least one-third of my time is spent traveling around the world, meeting people, speaking about climate change and sustainable development and trying to foster global citizenship especially for young people. What I observe is there clearly is a need for global citizenship. That is exactly right. We are having troubles around the world. We need global vision.

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.

A deal must include an equitable global governance structure. All countries must have a voice in how resources are deployed and managed.

You are here to step into the shoes of UN ambassadors - to draft resolutions, to plot strategy, to negotiate with your allies as well as your adversaries. Your goal may be to resolve a conflict, to cope with a natural disaster or to bring nations together on an issue like climate change. You may be playing a role, but you are also preparing for life. You are acting as global citizens.

I call for the need of world leaders to address climate change and reduce the increasing risk of disasters- and world leaders must include mayors, townships and community leaders.