( ( ( ( ( Thus ( ( ( the amount ) ( of ( ( carbon dioxide ) ( in ( the atmosphere ) ) ) ) ) ( steadily increases ) ) ) , ) and ) ( it ( is ( said ( that ( ( by ( the ( years 2025-2050 ) ) ) ( , ( there ( will ( ( by ( ( twice ( as much ) ) ( in ( the atmosphere ) ) ) ) ( as ( there ( was ( before industrialization ) ) ) ) ) ) ) ) ) ) ) ) ) ) . )
(ROOT (S (S (ADVP (RB Thus)) (NP (NP (DT the) (NN amount)) (PP (IN of) (NP (NP (NN carbon) (NN dioxide)) (PP (IN in) (NP (DT the) (NN atmosphere)))))) (ADVP (RB steadily)) (VP (VBZ increases))) (, ,) (CC and) (S (NP (PRP it)) (VP (VBZ is) (VP (VBN said) (SBAR (IN that) (S (PP (IN by) (NP (DT the) (NNS years) (NN 2025-2050))) (, ,) (NP (EX there)) (VP (MD will) (VP (PP (IN by) (NP (NP (QP (RB twice) (RB as) (JJ much))) (PP (IN in) (NP (DT the) (NN atmosphere))))) (SBAR (IN as) (S (NP (EX there)) (VP (VBD was) (PP (IN before) (NP (NN industrialization))))))))))))) (. .)))
Thus the amount of carbon dioxide in the atmosphere steadily increases, and it is said that by the years 2025-2050, there will by twice as much in the atmosphere as there was before industrialization.
(ROOT (S (PP (IN During) (NP (DT the) (JJ early) (NN paleozoic))) (, ,) (NP (NP (DT the) (NN amount)) (PP (IN of) (NP (NP (NN carbon) (NN dioxide)) (PP (IN in) (NP (DT the) (NN atmosphere)))))) (VP (VBD was) (ADJP (RB much) (JJR greater)) (PP (VBN compared) (PP (TO to) (NP (NN today))))) (. .)))