Already three of the world’s major geopolitical powers and biggest greenhouse gas emitters –Brazil, China, and the US – have announced their climate commitments ahead of this year’s crucial COP. Barack Obama and Dilma Rousseff preside over more than half a billion people, so their climate pledges bring heavy clout.

Both Presidents have agreed to sharply expand renewable energies - the US to triple its renewable power energy and Brazil to more than double its clean energy production.

Brazil have also pledged to restore 12 million hectares of Amazon forest by 2030 (about the size of England) which will reverse Brazil’s twentieth century trend of shrinking forests and move to a new globally-beneficial trend of expanding forests.

The global climate pact is gaining terrific momentum with the USA’s, China’s, and Brazil’s commitments being brokered more than 4 months before the Climate Summit in Paris. President Obama is urging India and other major economies to follow suit.

“Following progress during my trips to China and India, this shows that the world’s major economies can begin to transcend some of the old divides and work together to confront the common challenge that we face — something that we have to work on for future generations,” said President Obama, who has pushed other countries to sign on to a climate change deal.

In this bilateral deal, President Rousseff echoed the pivotal importance for the world to broker an effective deal to halt global warming: “Climate change is one of the central challenges of the 21st century,” she said. “And we have one important objective, which is, number one, to ensure that the energy mix in our two countries will have a substantial share of renewable sources of energy”.