( ( ( ( ( ( The ( greenhouse effect ) ) , ) and ) ( ( ( humans ' ) understanding ) ( of it ) ) ) , ) ( ( ( is not ) new ) . ) )
(ROOT (S (NP (NP (DT The) (NN greenhouse) (NN effect)) (, ,) (CC and) (NP (NP (NP (NNS humans) (POS ')) (NN understanding)) (PP (IN of) (NP (PRP it)))) (, ,)) (VP (VBZ is) (RB not) (ADJP (JJ new))) (. .)))
The greenhouse effect, and humans' understanding of it, is not new.
(ROOT (S (NP (NNP Human) (NNS actions)) (VP (VBZ has) (VP (VBN increased) (NP (DT the) (NN greenhouse) (NN effect)))) (. .)))