( ( The ( greenhouse effect ) ) ( ( ( is already ) ( ( ( causing ( ( the melting ) ( of ( polar ( ice caps ) ) ) ) ) and ) ( ( playing havoc ) ( with ( ( weather systems ) ( around ( the world ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NN greenhouse) (NN effect)) (VP (VBZ is) (ADVP (RB already)) (VP (VP (VBG causing) (NP (NP (DT the) (NN melting)) (PP (IN of) (NP (JJ polar) (NN ice) (NNS caps))))) (CC and) (VP (VBG playing) (NP (NN havoc)) (PP (IN with) (NP (NP (NN weather) (NNS systems)) (PP (IN around) (NP (DT the) (NN world)))))))) (. .)))
The greenhouse effect is already causing the melting of polar ice caps and playing havoc with weather systems around the world.
(ROOT (S (NP (JJS Most) (NNS scientists)) (VP (VBP agree) (SBAR (IN that) (S (NP (NP (DT an) (NN increase)) (PP (IN in) (NP (NP (DT the) (NN amount)) (PP (IN of) (NP (NP (NN greenhouse) (NNS gases)) (VP (VBG entering) (NP (NP (NN earth) (POS 's)) (NN atmosphere)))))))) (VP (VBZ causes) (NP (NP (DT an) (NN increase)) (PP (IN in) (NP (NP (NN melting)) (PP (IN of) (NP (JJ polar) (NN ice) (NNS caps)))))))))) (. .)))
Most scientists agree that an increase in the amount of greenhouse gases entering earth's atmosphere causes an increase in melting of polar ice caps.