( But ( ( buying ( clean energy ) ) ( ( is ( ( just ( one issue ) ) ( in ( determining ( total ( greenhouse ( gas emissions ) ) ) ) ) ) ) . ) ) )
(ROOT (S (CC But) (S (VP (VBG buying) (NP (JJ clean) (NN energy)))) (VP (VBZ is) (NP (NP (RB just) (CD one) (NN issue)) (PP (IN in) (S (VP (VBG determining) (NP (JJ total) (NN greenhouse) (NN gas) (NNS emissions))))))) (. .)))
But buying clean energy is just one issue in determining total greenhouse gas emissions.
(ROOT (S (NP (JJ Geothermal) (NN energy) (NN energy)) (VP (VP (VBZ is) (ADJP (JJ clean))) (CC and) (VP (VBZ does) (RB not) (VP (VB release) (NP (NN greenhouse) (NNS gases))))) (. .)))