At the end of this year, I will be finishing my term as Secretary-General of the United Nations. As I prepare to leave, I look at the world with a mixture of dismay and optimism.

Huge challenges confront the human race — from global warming and poverty to terrorism and weapons of mass destruction.

But there is also real hope that we can come together to address them.

On the plus side, aid and debt relief are helping to make the world economy less unjust and governments are finally beginning to take HIV/Aids as seriously as it deserves. There are fewer wars between states and many wars within states have ended.

There are more governments elected by those they govern, and accountable to them. And all the world’s governments have agreed — at least on paper — that they have a responsibility to protect people from genocide, war crimes, ethnic cleansing and crimes against humanity.

But on the minus side, the world is not on track to meet all the Millennium Development Goals — agreed six years ago by world leaders as a blueprint for a better world in the 21st century — by the target date of 2015. People still face brutal conflicts, especially in the developing world. We risk a cascade of new countries — and perhaps terrorists — acquiring nuclear or biological weapons. Even without this, terrorism continues to sow fear and suspicion between religions and races.

And every day reports reach us of new laws broken and new heinous crimes inflicted on individuals and minority groups.

People in different countries don’t even agree which of these threats are most important. Some say it’s global warming, some terrorism. Others say Aids, poverty or crime.

The truth is, we need to be concerned about all of them. And that means we must work for a truly United Nations. People need to be bound together by something more than just a global market.

The strong, as well as the weak, need to agree to be bound by the same rules. Nations need to come together, not at cross purposes but with a common purpose, to shape our common destiny.

Over the past decade I have worked in partnership with the UN’s member states to move the world in this direction.

We have pushed some big rocks to the top of the mountain, even if others have slipped from our grasp and rolled back.

It’s been a difficult and challenging ten years but at times thrillingly rewarding. And while I look forward to resting my shoulder from those stubborn rocks, I know I shall miss the mountain.

I shall miss what is, when all is said and done, the world’s most exalting job.

I yield my place to others with a real obstinate feeling of hope for our common future.