(S (BASENP (PRP He)) (VP (ADVP (RB also)) (VP (VBD warned) (SBAR (IN that) (S (NP (NP (QP (ADVP (RB up) (TO to)) (BASENP (NN 250) (NN million))) (NNS people)) (PP (IN in) (BASENP (NNP Africa)))) (VP (MD could) (VP (VB face) (SBAR (WHNP (WP what)) (S (BASENP (PRP he)) (VP (VBD called) (QT (DQL ``) (QTC (S (NP (BASENP (VBN increased) (NN water) (NN stress)) (PP (IN because) (PP (IN of) (BASENP (NN climate) (NN change)))))) (PERIOD .)) (DQR ''))))))))))))