Just four years ago, there were plans to build 150 new coal-fired power plants in the United states. Just 14 of these are still being actively pursued and all of these are still subject to legal action on environmental grounds.

"The enormity of what they were proposing to do provided a platform to have that whole debate about pollution, including global-warming pollution, " says Bruce Nilles, director of the national coal campaign for the Sierra Club, America’s biggest grassroots environment group.

The backlash against coal power in America has become the country’s biggest-ever environmental campaign, transforming the nation’s awareness of climate change and inspiring political leaders to take firmer action after years of doubt and delay. Six states – California, Washington, Oregon  Florida, Idaho and Kansas – have imposed effective moratoriums on new coal-fired power station.

As well as highlighting the direct environmental damage from coal mining, US activists have targeted.banks, telling them that investing in coal might be too risky because of the threat of international emissions caps and high carbon prices, prompting the banks to set tougher conditions on lending. They have highlighted little-noticed government subsidies to the coal industry and mounted legal challenges on the basis that burning coal was not the cheapest way of generating electricity (which is a legal requirement on some state governments).

Similar actions are beginning to target coal-fired power stations around the world.  In Germany, campaigners have won local referendums blocking coal-fired power plants. In the UK, protesters have set up a camp against the development of the first coal-fired plant proposed for two decades. Protests have been held against building a plant at Chamalapura near Mysore in India. And in China, there were an estimated 51,000 pollution-related protests in 2006.

The Sierra Clubs’s Bruce Niles believes that the building of new coal-fired power stations in the US will soon be stopped and that protesters will turn their attention to existing coal power and the mining industry. He says, "Ultimately, we need to phase out coal entirely. We don’t need it and it’s very expensive."