Weapons of mass destruction violate more than individual lives - they cross international borders and jeopardize all people. They also drain resources that could be used instead for medicines, schools and other life-saving supplies. We must come together with even greater determination to prevent a WMD nightmare.
Every day, we at the United Nations see the human toll of an absence of regulations or lax controls on the arms trade. We see it in the suffering of civilian populations trapped by armed conflict or pervasive crime. We see it in the killing and wounding of civilians - including children, the most vulnerable of all.
Border strengthening is effective, but not if done in isolation. We also need to give priority to establishing public institutions that deliver a sustained level of security and justice for citizens. Border security can never come at the expense of migrants' rights. Nor can it be used to legitimize inhumane treatment.
We have reached a new milestone as a human family. With seven billion of us now inhabiting our planet, it is time to ask some fundamental questions. How can we provide a dignified life for ourselves and future generations while preserving and protecting the global commons - the atmosphere, the oceans and the ecosystems that support us?
Throughout human history, in any great endeavour requiring the common effort of many nations and men and women everywhere, we have learned - it is only through seriousness of purpose and persistence that we ultimately carry the day. We might liken it to riding a bicycle. You stay upright and move forward so long as you keep up the momentum.
One of the main lessons I have learned the last five years as Secretary-General is that the United Nations cannot function properly without the support of the business community and civil society. We need to have tripartite support - the governments, the business communities and the civil society.
Climate change, in some regions, has aggravated conflict over scarce land, and could well trigger large-scale migration in the decades ahead. And rising sea levels put at risk the very survival of all small island states. These and other implications for peace and security have implications for the United Nations itself.
It is a sad but undeniable reality that people have died in the line of duty since the earliest days of the United Nations. The first was Ole Bakke, a Norwegian member of the United Nations guard detachment, shot and killed in Palestine in 1948. The toll since then has included colleagues at all levels.