51.   And if the Clinton administration has its way, a similar system of market-based permits will someday be used to limit global emissions of greenhouse gases.

52.   And it has voluntarily decided to curb emissions of greenhouse gases, and is building an internal carbon-trading scheme.

53.   And the EPA fears a rise in greenhouse gasses because, as light trucks, all sport utilities are allowed to produce more fumes than cars.

54.   And what could the United States actually do to reduce its emission of greenhouse gases?

55.   And yet we continue, with very little restraint, to spew out the so-called greenhouse gases.

56.   And when burned, the trees spew greenhouse gases that fuel global warming.

57.   Any serious American effort to reduce greenhouse gases will require sacrifice.

58.   Any serious plan to reduce greenhouse gases will carry political risks because it will not be cost-free.

59.   ANEW REPORT this week has demonstrated the importance of concerted international action to curb greenhouse gases.

60.   As a result of this and other complex global atmospheric changes, levels of greenhouse gases soared.