Companies wanting to demonstrate corporate social responsibility by being a member of the FTSE4Good stock market index will be forced to show they are reducing their carbon emissions.
About a quarter of the energy-intensive users in the FTSE4Good are heading for removal unless they change their ways, according to the index's organisers.
Oil companies, airlines and mining firms will be told today they must deliver a 2.5% per annum reduction in carbon emissions and publish specific climate-change policies for which their boards must take direct responsibility under a first phase of the new initiative that will gradually be rolled out for all members.
US companies look under particular threat under the criteria to be announced at Canary Wharf in London today with a keynote speech from the environment secretary, David Miliband. "It used to be accepted that we cannot afford to be green. Now the opposite is true: we cannot afford not to be," he will argue.
Craig Morrison, head of business ethics at Glasgow Caledonian University and a FTSE4Good committee member, said last night that some companies were working very hard to reduce their carbon footprint but "incredibly" some were failing badly and letting their pollution levels rise.
"We will give companies time for change but after that they will be removed from the index if they do not show that they are making improvements," he said.
FTSE4Good already demands higher environmental standards but today the criteria will be raised to include CO2 emissions and climate change for the first time.
Mr Morrison accepts that a 2.5% decrease is not much to ask. "We could have made it 5% but quite honestly it would have decimated the index - removing 60% or 70% of the constituents."
Mr Miliband will also argue that environmentalists who push punitive measures on business "must not forget that without a stable and prosperous economy the public appetite for green measures will dwindle".