In January the EPA began requiring large polluters to carry permits to emit greenhouse gases.

Under the EU's cap and trade system, major polluters are given allowances to emit greenhouse gases.

Both the extraction process, and the burning of it as a fuel, emit greenhouse gases into the atmosphere.

She said potential EPA rules could force many farms to get permits to emit greenhouse gases or slow operations.

And heavy cargo planes flying overseas emit greenhouse gasses and pollution that could be avoided by more local shipments.

U.S. utilities also urged lawmakers on Thursday to provide power companies with free permits to emit greenhouse gases, at least initially.

Next year it will require big emitters such as power plants, manufacturers, and refineries to hold permits to emit greenhouse gases.

The Environmental Protection Agency is also trying to put modest regulations on big power plants and factories that emit greenhouse gases.

Carbon credits are bought by companies who have no option but to emit greenhouse gases if they want to stay in business.

Allocations of permits to emit greenhouse gases will be decided on an EU-wide basis, rather than through national allocation plans as at present.

Such programs set an overall emissions limit, then requires participants, often energy-intensive industries, to buy permits to emit greenhouse gases like carbon dioxide.

Since nuclear energy does not emit greenhouse gases it must be seriously considered as a player in any future mix of power generation technologies.

Governments seeking to combat global warming are giving incentives for low-carbon energy production and penalizing industries that emit greenhouse gas emissions from fossil fuels.

Renewables are attracting investments in a shift from fossil fuels that emit greenhouse gases linked to rising temperatures, more droughts, floods and rising seas.

Renouncing bog harvesting, they say, is too little, too late -a false solace because the ravaged peatlands will continue to emit greenhouse gases.

We must act on two broad fronts: reducing activities that emit greenhouse gases, and increasing activities that draw gases, already emitted, out of the atmosphere.