The UK must prioritise growth in "green industries" such as energy efficiency and renewable energy, David Cameron said on Monday.
The prime minister has come under fire from environmentalists for a perceived lack of leadership on environmental issues, with the chief executive of WWF UK, David Nussbaum, warning in November "he seems to have lost his voice" and that his "continued silence would be a betrayal not just of election promises, but of the UK national interest."
Last week, former US vice president Al Gore said he was "worried there are influences in his party that have backed him off."
But speaking on Monday, Cameron said that "to those who say we just can't afford to prioritise green energy right now, my view is we can't afford not to".
"Make no mistake, we are in a global race and the countries that succeed in that race, the economies in Europe that will prosper are those that are the greenest and the most energy-efficient. Energy consumption is set to grow by a third over the next two decades alone. And in a race for limited resources it is the energy-efficient that will win that race,".
He added that "it is the countries that prioritise green energy that will secure the biggest share of jobs and growth."
According to the CBI, the green economy is now worth more than £120bn a year, or 8% of GDP, and was one of the few areas of the economy to experience growth in 2012.