Fig. 3.

Zonal mean monthly precipitation (1a, 2a, 3a), used for simulating biomes (1b, 2b, 3b) and NPP (1c, 2c, 3c) at 9 ka with the CARAIB vegetation model. The three simulations were performed using the following: 1) HadCM3 9 ka climatology (47); 2) 300-mm precipitation added each year to modern values, only during the monsoon season, over the whole simulated area; and 3) an increase of 300-mm precipitation each year below 18° N in the summer season only, above 24° N in the DJF season only, and with a progressive transition between 18 and 24° N, where precipitation occurs in both JJA and DJF (SI Appendix, Table S2). The data for simulations 2 and 3 are available in the SI Appendix.