Protecting the environment can boost rather than hinder economic growth, Chancellor Gordon Brown has said.
Mr Brown denies by rattled by Tory stress on green issues
In a speech to the United Nations in New York, Mr Brown said "great statesmanship" was needed to provide a global solution to climate change.
The chancellor has denied being rattled by Conservative leader David Cameron's recent emphasis on green issues.
Mr Cameron is visiting northern Norway to study the effects of global warming on glaciers.
During his US trip, Mr Brown is expected to discuss oil at a G8 meeting in Washington.
But his first task is his speech on the "global challenge of environmental change".
He told UN ambassadors boosting the economy and protecting the environment were far from being at odds with each other.
"Environmental sustainability is not an option, it is a necessity," he said.
"For economies to flourish, for global poverty to be banished, for the well-being of the world's people to be enhanced... we have a compelling and ever-more-urgent duty of stewardship to take care of the natural environment and resources on which our economic activity and social fabric depends."
Earlier, he told BBC News he was more optimistic than ever there could be an international consensus.
He said countries were increasingly recognising the need to act on high oil prices by moving to a more diverse range of energy supplies.
And there were huge opportunities to use new science and technology to meet energy needs in an environmentally friendly way.
This weekend Mr Brown will also propose a new World Bank project to encourage developing countries to use alternative sources of energy or use existing sources more efficiently.
He said: "I think companies and governments are now prepared to act in a way they have not been prepared to act before...
"Most of all I think there is now a shared understanding of the problem and a growing sense that we have got to build a shared consensus about how we solve it."
The Tory leader has been trying to highlight his party's green credentials but the chancellor denied he was rattled and trying to hit back with a "Brown is green" message.
"The big issue on the environment is whether politicians can move beyond words to talking about substantive policies that are necessary," he said.
The government had taken action through the climate change levy and the Tories must propose an alternative if they wanted to scrap it - something they say they will do.
Mr Cameron cycles into work and is installing a wind turbine into his home while Liberal Democrat leader Sir Menzies Campbell is giving up his Jaguar car.
But Mr Brown was reluctant to give details of his personal contribution to the environment, aside from saying he is swapping his official car for a greener model.
He said there had to a mixture of individual responsibility and community action.
Mr Cameron says he wants to see first hand the effects of climate change during his Norway trip.
But some are saying he would be better off knocking on doors in the lead up to the local elections.
Other political parties have criticised his trip for being just a photo opportunity.
The Greens also attacked Labour's record, saying Mr Brown and Tony Blair had "abysmally failed" to act over the last decade.
The Greens' principal speaker, Keith Taylor, said: "Tony Blair has presided over the biggest expansion of the aviation sector - the fastest growing contributor to climate change - in a generation, with the full support of the Tories."
He also criticised road building under Labour.