Climate change has happened because of human behaviour, therefore it’s only natural it should be us, human beings, to address this issue. It may not be too late if we take decisive actions today.

Between now and 2015, we must make sure that promises made become promises kept. The consequences of doing otherwise are profound: death, illness and despair, needless suffering, lost opportunities for millions upon millions of people.

The international community must offer short-term emergency measures to meet critical needs. But it must also make longer-term investments to promote food production and agricultural development, enhance food security and maintain and accelerate momentum towards the MDGs.

One of the main lessons I have learned during my five years as Secretary-General is that broad partnerships are the key to solving broad challenges. When governments, the United Nations, businesses, philanthropies and civil society work hand-in-hand, we can achieve great things.

We must turn the greatest collective challenge facing humankind today – climate change – into the greatest opportunity for common progress towards a sustainable future.

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.

People everywhere look to the United States to use its remarkable power to help lift humanity up and to work for the common good.