The basic building block of peace and security for all peoples is economic and social security, anchored in sustainable development. It is a key to all problems. Why? Because it allows us to address all the great issues-poverty, climate, environment and political stability-as parts of the whole.

You are already leaders. Your ideas, your actions and your decisions make a difference. More than any other generation, you have a voice. Social networking is changing how we interact - and it can change our world. You are in touch with peers from around the world. You understand the power of instant communication. I appeal to you to use that power for the common good, the power of communication and the power of networking.

Saving our planet, lifting people out of poverty, advancing economic growth... these are one and the same fight. We must connect the dots between climate change, water scarcity, energy shortages, global health, food security and women's empowerment. Solutions to one problem must be solutions for all.

Climate change...is, simply, the greatest collective challenge we face as a human family.

It has been said that knowledge is power. We need to strengthen education systems so that young people can benefit from cultural diversity, and not be victimized by those who exploit differences.

Violence against women continues to persist as one of the most heinous, systematic and prevalent human rights abuses in the world. It is a threat to all women, and an obstacle to all our efforts for development, peace, and gender equality in all societies. Violence against women is always a violation of human rights; it is always a crime; and it is always unacceptable. Let us take this issue with the deadly seriousness that it deserves.

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.