(S (S (BASENP (NNP Federal) (NNP Environment) (NNP Minister) (NNP Ian) (NNP Campbell)) (VP (VBD said) (SBAR (S (BASENP (PRP he)) (VP (VBD recognized) (SBAR (S (BASENP (NN climate) (NN change)) (VP (VBD was) (BASENP (DT the) (JJS biggest) (JJ modern-day) (JJ environmental) (NN challenge)))))))))) (PERIOD .))