294
Table 16.2 Average aridity indices for two periods, difference between periods, and trends for
Mexico by type of land
Aridity statistics
COMUNAL_TUC
REST
Grand total
Average of Index6190
Arid
0.137
0.154
0.148
Dry-subhumid
0.621
0.630
0.627
Hyper-arid
0.053
0.053
NA
1.026
1.058
1.048
Semi-arid
0.410
0.397
0.401
Average of Index 9117
Arid
0.129
0.143
0.138
Dry-subhumid
0.578
0.574
0.576
Hyper-arid
0.045
0.045
NA
0.973
1.007
0.996
Semi-arid
0.364
0.350
0.353
Average of difference
Arid
−0.008
−0.011
−0.010
Dry-subhumid
−0.043
−0.055
−0.052
Hyper-arid
−0.008
−0.008
NA
−0.054
−0.051
−0.052
Semi-arid
−0.047
−0.048
−0.048
Average of trend
Arid
0.000
0.000
0.000
Dry-subhumid
−0.001
−0.002
−0.002
Hyper-arid
0.000
0.000
NA
−0.002
−0.002
−0.002
Semi-arid
−0.001
−0.001
−0.001
Total average of Index6190
0.661
0.653
0.656
Total average of Index9117
0.617
0.608
0.611
Total average of difference
−0.044
−0.046
−0.045
Total average of trend
−0.001
−0.001
−0.001
Communal_TUC = communal lands within Ejidos, REST = Any land that does not include RAN
or TUC in Mexico
the spectrum. This suggests that we might see an increase in areas newly categorized as arid in regions where humid climates predominated in the past (e.g., NA
areas converting to dry-subhumid).
Discussion and Conclusions
The analyses presented in this chapter allow us to explore several dimensions and
scales of aridification in Latin America. We first analyzed the changes in aridity as
measured by the aridity index over two periods of time (1961–1990 and
E. Nickl et al.