( There ( ( ( is concern ) ( that ( ( the ( greenhouse effect ) ) ( is ( being ( altered ( due ( to ( ( increased concentrations ) ( of ( GHGs ( resulting ( from ( human activities ) ) ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (EX There)) (VP (VBZ is) (NP (NN concern)) (SBAR (IN that) (S (NP (DT the) (NN greenhouse) (NN effect)) (VP (VBZ is) (VP (VBG being) (VP (VBN altered) (PP (JJ due) (TO to) (NP (NP (VBN increased) (NNS concentrations)) (PP (IN of) (NP (NP (NNP GHGs)) (VP (VBG resulting) (PP (IN from) (NP (JJ human) (NNS activities)))))))))))))) (. .)))
There is concern that the greenhouse effect is being altered due to increased concentrations of GHGs resulting from human activities.
(ROOT (S (NP (NNP Human) (NNS actions)) (VP (VBZ has) (VP (VBN increased) (NP (DT the) (NN greenhouse) (NN effect)))) (. .)))