( ( but ( ( when ( ( the earth ) ( ( s ( surface ( reradiates energy ) ) ) ( back ( to space ) ) ) ) ) ( , ( ( ( a ( significant portion ) ) ( of ( this ( thermal radiation ) ) ) ) ( is ( ( ( absorbed and ) reradiated ) ( by ( the atmosphere ) ) ) ) ) ) ) ) ( ( ( s ( ( CO ( ( 2 molecules ) back ) ) ( to ( the earth ) ) ) ) ( ( ( s surface ) , ) ( ( incrementally warming ) ( the planet ) ) ) ) . ) )
(ROOT (SINV (S (CC but) (SBAR (WHADVP (WRB when)) (S (NP (DT the) (NN earth)) (VP (VBZ s) (NP (NN surface) (NNS reradiates) (NN energy)) (ADVP (RB back) (PP (TO to) (NP (NN space))))))) (, ,) (NP (NP (DT a) (JJ significant) (NN portion)) (PP (IN of) (NP (DT this) (JJ thermal) (NN radiation)))) (VP (VBZ is) (VP (VBN absorbed) (CC and) (VBN reradiated) (PP (IN by) (NP (DT the) (NN atmosphere)))))) (VP (VBZ s) (VP (VBG CO) (ADVP (NP (CD 2) (NNS molecules)) (RB back)) (PP (TO to) (NP (DT the) (NN earth))))) (NP (NP (JJ s) (NN surface)) (, ,) (NP (NP (JJ incrementally) (NN warming)) (NP (DT the) (NN planet)))) (. .)))
but when the earth s surface reradiates energy back to space, a significant portion of this thermal radiation is absorbed and reradiated by the atmosphere s CO 2 molecules back to the earth s surface, incrementally warming the planet.
(ROOT (S (NP (NP (NNS Gases)) (PP (JJ such) (IN as) (NP (NN co2) (CC and) (NN methane)))) (VP (MD can) (VP (NN trap) (NP (NP (JJ thermal) (NN energy)) (PP (IN in) (NP (NP (NN earth) (POS 's)) (NN atmosphere)))) (PP (IN before) (S (VP (VBG radiating) (NP (PRP it)) (PP (IN into) (NP (NN space)))))))) (. .)))