00458nam a2200157Ia 4500080001700000040001600017011003100033245010500064260004700169300000900216500001500225650001700240650002500257010000900282010000900291 a502.3 COM ch aBIEFCVbPor aCommitee on Earth Sciences aOur changing planet: cthe FY 1991 U.S. global change research prográm/ Commitee on Earth Sciences aReston:bCommitee on Earth Sciences,c1991 a60p. aexemplares aAmbiente-USA aPolítica ambiental atrue atrue