Twenty years ago the first Earth Summit took place in Rio. That Summit which I had the privilege to attend was an attempt by the global community to change the course of human development to a more equitable and sustainable model.

Two decades later, significant progress has been made on the road to sustainability. But more fundamentally, today's world is a different place. The Rio+20 Summit takes place against a backdrop of a changing global landscape, an international economic crisis, rising global population levels, increasing global resource use and, despite all the progress, an unacceptable level of poverty. The community of states thus bears an even greater responsibility to move to a new stage in our collective search for inclusiveness and sustainability.

Today's economic crisis is not only a result of irresponsible behavior of some in the financial sector, coupled by lax regulatory oversight. It is also the result of deep-seated imbalances that need to be corrected if we want to generate more sustainable growth. These are not only global economic imbalances, they are also imbalances in our ecological footprint. During the 20th century, global economic output multiplied forty-fold and standards of living rose enormously. But this came at a price and was based on an unsustainable use of scarce global resources, such as fuels, metals, minerals, timber, water, and ecosystems. By 2050 the world's population will have reached 9 billion, so the imperative to act together is undeniable. If we do not meet this challenge, we will need the equivalent of two planets to sustain us.