Former Prime Minister Tony Blair said that tackling global warming during the economic downturn was important if the world was to avoid the future costs of climate change.
In an interview with CNN, Mr Blair said that in the long-term, the price of environmental and weather change would be much more than if measures to curb emissions were not implemented.
The former British leader urged US president Barack Obama to continue with "a bold, assertive line" from the beginning on global warming as he also tackled the challenges of economic crisis and security threat.
Asked if he thought Mr Obama was overreaching in the first few weeks of his administration, Mr Blair said: "It would be neat in a way to say, 'Let's deal with the global economic crisis first, then move on to the security threat and then deal with global warming'.
"I'm afraid they are all there and in the entree and that is why, no, I think on the contrary - by taking a very bold, assertive line from the beginning, I think his leadership is giving people some hope that these problems that are major and difficult - difficult challenges to meet - will be met."
Mr Blair was in Washington to attend a global symposium on the response to climate change.
Asked if it was wise to push forward with taxes and caps to reduce carbon emissions at a time of economic strife, Mr Blair said that it was not about imposing a burden, but giving people an opportunity to cut their electricity bills.
He told CNN: "We were hearing from business people, American power companies, business people, people who are there to make a profit that are also saying how by introducing energy saving devices the consumer could actually cut the amount of money it was paying on its energy bills. So there are opportunities here, as well. Yes, of course, there are big challenges, but there are opportunities.
"And if you think going forward if we don't resolve this problem and we end up with major climate change happening, it's going to impact here and it's going to impact right around the world and of course impose its own cost."
He added that during the global climate change symposium, he presented a study showing how much more the world would have to pay if it did not deal with major environmental and weather change problems.