( ( ( ( Carbon ( ( dioxide ( -LRB- ( CO2 -RRB- ) ) ) ( gas ( generated ( by ( ( ( man 's ) burning ) ( of ( fossil fuels ) ) ) ) ) ) ) ) and ) ( ( the forests ) ( is ( responsible ( for ( ( about half ) ( the ( greenhouse ( gas warming ) ) ) ) ) ) ) ) ) . )
(ROOT (S (S (NP (NNP Carbon)) (VP (VBZ dioxide) (PRN (-LRB- -LRB-) (NP (NNP CO2)) (-RRB- -RRB-)) (NP (NP (NN gas)) (VP (VBN generated) (PP (IN by) (NP (NP (NP (NN man) (POS 's)) (NN burning)) (PP (IN of) (NP (JJ fossil) (NNS fuels))))))))) (CC and) (S (NP (DT the) (NNS forests)) (VP (VBZ is) (ADJP (JJ responsible) (PP (IN for) (NP (NP (QP (RB about) (PDT half))) (NP (DT the) (NN greenhouse) (NN gas) (NN warming))))))) (. .)))
Carbon dioxide (CO2) gas generated by man's burning of fossil fuels and the forests is responsible for about half the greenhouse gas warming.
(ROOT (S (NP (JJ Co2) (NN gas)) (VP (VBZ is) (VP (VBN released) (PP (IN into) (NP (NP (DT the) (NN atmosphere)) (SBAR (WHADVP (WRB when)) (S (NP (JJ fossil) (NNS fuels)) (VP (VBP are) (VP (VBN burned))))))))) (. .)))