309
economic sectors going from agriculture to public health. Aridity indices are based
on the precipitation occurred throughout the year (as a source of water) and on the
temperatures (as an indicator of the evaporation capacity of the climate). For example, Lang’s index (Hubálek and Horáková 1988) is an explicit and easily applicable
measurement for estimating the magnitude of dryness that allows an evaluation of
the changes in the distribution of drought and—with temperature and precipitation
outputs from general circulation models of climate change—allows to calculate its
future projections (Sánchez-Torres et al. 2011). Consequently, the dryness exposure
index was calculated through the Lang’s drought index as described below, both for
the current situation (reference climatology) as for one and two horizon models
(GFDL-CM3 and MPI-ESM-LR climate model outputs for medium term [2015–
2069] RCP 8.5 scenarios). Form then on the significance of GFDL_CM3 and MPI_
ESM_LR terms would be explained
1
.
Present and Future Scenarios
Different methods for the delimitation and characterization of arid and semi-arid
zones have been proposed and used for the numerical quantification of drought and
for its application in the interpretation of the aridity process, one of the alternatives
applied in this type of studies being the calculation of the PP/Tm ratio (Amador
et al. 2011), published and referred to as Lang’s index (Hubálek and Horáková
1988; Sánchez-Torres et al. 2011). We proposed to use Lang’s index, which, as
mentioned above, is a thermo-pluviometric index calculated by dividing the average
annual precipitation (in mm) by the average annual temperature (in ° C):
Pf PP Tm,
=
/
where PP is the annual precipitation in mm; Tm is the average temperature in °C.
Climatological data were used for the current situation and Lang’s index was
calculated with the temperature and precipitation values corresponding to the outputs of the different models for the future projections and the selected climate
change scenarios. Municipalities were classified according to the standard categories proposed by Troyo-Diéguez et al. (2014, Table 17.4). To quantify the changes
of exposure to dryness along the coasts, Lang’s index values and categories were
1 Climate change projections have been developed at a global scale considering different scenarios.
General Circulation Models (GCM) and are used to predict climate change for different future time
periods under different CO2 emission scenarios and related atmospheric heat transfer processes. In
this work we choose the highest emissions pathways (Representative Concentration Pathways
RCP 8.5), which assumes that greenhouse gas emissions will continue to rise throughout the current century, so that we could distinguish larger change. Two models from the world available
GCM considered to represent the best climate regime for Mexico were analyzed: GFDL_CM3
(developed by the Geophysical Fluid Dynamics Laboratory), and MPI_ESM_LR (developed by
the Max-Plank Institute).
17 Vulnerability to the Effects of Climate Change: Future Aridness and Present…
economic sectors going from agriculture to public health. Aridity indices are based
on the precipitation occurred throughout the year (as a source of water) and on the
temperatures (as an indicator of the evaporation capacity of the climate). For example, Lang’s index (Hubálek and Horáková 1988) is an explicit and easily applicable
measurement for estimating the magnitude of dryness that allows an evaluation of
the changes in the distribution of drought and—with temperature and precipitation
outputs from general circulation models of climate change—allows to calculate its
future projections (Sánchez-Torres et al. 2011). Consequently, the dryness exposure
index was calculated through the Lang’s drought index as described below, both for
the current situation (reference climatology) as for one and two horizon models
(GFDL-CM3 and MPI-ESM-LR climate model outputs for medium term [2015–
2069] RCP 8.5 scenarios). Form then on the significance of GFDL_CM3 and MPI_
ESM_LR terms would be explained
1
.
Present and Future Scenarios
Different methods for the delimitation and characterization of arid and semi-arid
zones have been proposed and used for the numerical quantification of drought and
for its application in the interpretation of the aridity process, one of the alternatives
applied in this type of studies being the calculation of the PP/Tm ratio (Amador
et al. 2011), published and referred to as Lang’s index (Hubálek and Horáková
1988; Sánchez-Torres et al. 2011). We proposed to use Lang’s index, which, as
mentioned above, is a thermo-pluviometric index calculated by dividing the average
annual precipitation (in mm) by the average annual temperature (in ° C):
Pf PP Tm,
=
/
where PP is the annual precipitation in mm; Tm is the average temperature in °C.
Climatological data were used for the current situation and Lang’s index was
calculated with the temperature and precipitation values corresponding to the outputs of the different models for the future projections and the selected climate
change scenarios. Municipalities were classified according to the standard categories proposed by Troyo-Diéguez et al. (2014, Table 17.4). To quantify the changes
of exposure to dryness along the coasts, Lang’s index values and categories were
1 Climate change projections have been developed at a global scale considering different scenarios.
General Circulation Models (GCM) and are used to predict climate change for different future time
periods under different CO2 emission scenarios and related atmospheric heat transfer processes. In
this work we choose the highest emissions pathways (Representative Concentration Pathways
RCP 8.5), which assumes that greenhouse gas emissions will continue to rise throughout the current century, so that we could distinguish larger change. Two models from the world available
GCM considered to represent the best climate regime for Mexico were analyzed: GFDL_CM3
(developed by the Geophysical Fluid Dynamics Laboratory), and MPI_ESM_LR (developed by
the Max-Plank Institute).
17 Vulnerability to the Effects of Climate Change: Future Aridness and Present…