( ( The ( arctic ice ) ) ( ( is ( melting ( which ( is ( ( causing ( an increase ) ) ( in ( ( the amount ) ( of ( heat ( retained ( at ( the ( Earths poles ) ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (JJ arctic) (NN ice)) (VP (VBZ is) (VP (VBG melting) (SBAR (WHNP (WDT which)) (S (VP (VBZ is) (VP (VBG causing) (NP (DT an) (NN increase)) (PP (IN in) (NP (NP (DT the) (NN amount)) (PP (IN of) (NP (NP (NN heat)) (VP (VBN retained) (PP (IN at) (NP (DT the) (NNP Earths) (NNS poles)))))))))))))) (. .)))
The arctic ice is melting which is causing an increase in the amount of heat retained at the Earths poles.
(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.