One hundred years of climate change in Mexico

throughout the country during the 20th century, as we also observed. They reported that cool- ing occurred mainly in the central and southern provinces of the country in the mid-century (1940–1969). In turn, we observed a decrease of the maximum temperature at the Sierra Madre Oriental and Soconusco provinces from t1-1940 to t2-1970, and an increase since t2- 1970 in the Sierra Madre Oriental, Golfo de Me´xico, Altos de Chiapas, and Yucata´n provinces. Our analyses demonstrate that the Neotropical region (Costa del Pacı´fico, Golfo de Me´xico, Depresio´n del Balsas, Oaxaca, Altos de Chiapas, Soconusco, Yucata´n, and Pete´n provinces) has exhibited a more pronounced decline in precipitation, probably as a consequence of an increase in the frequency and intensity of El Niño events in the last two decades [63]. Con- versely, precipitation and temperature [19] have shown an increase in some provinces of the north, namely, California, Sonorense, Altliplano Norte, and Tamaulipeca. However, precipita- tion is counterbalanced by evapotranspiration, and the combined effect of an increase in pre- cipitation and temperature can cause a larger vapor pressure deficit and evaporation, reducing Fig 5. Climate change in Mexico from t1-1910 to t3-2000. Negative and positive areas represent downwards and upwards changes, respectively, in annual precipitation (Bio 12), maximum temperature of the warmest month (Bio 05) and minimum temperature of the coldest month (Bio 06). Blue areas indicate negative signs (decrease)

for the difference between t1-1940–t2-1970 and t2-1970–t3-2000. Red areas indicate positive signs (increase) for the difference between t1-1940–t2-1970 and t2-1970–t3- 2000. White areas indicate that the sign between t1-1940–t2-1970 and t2-1970–t3-2000 were inconsistent. Biogeographic provinces reprinted from [57] under a CC BY license, with permission from [CONABIO], original copyright [1997]. https://doi.org/10.1371/journal.pone.0209808.g005 PLOS ONE Historical climate change in Mexico PLOS ONE | https://doi.org/10.1371/journal.pone.0209808 July 16, 2020 12 / 19