48
E. A. Agosta et al.
for ATOTP and R95pTOT using historical and RCP8.5 simulations, which represent
the most radical scenario concerning of global.
The historical ensemble means of ATOTP and annual R95pTOT over the baseline 1961–1990 are shown in Fig. 10, panels a and c, respectively. Their percentage
changes with respect to baseline, projected by the end of the current century (2075–
2099), are shown in panels b and d, respectively. Overall, the historical ensemble
means for both ATOTP (panel a) and R95pTOT (panel c) show similar spatial distribution and gradient from west to east and south to north. The percentage changes of
ATOTP show moderate change (panel b) compared to the present conditions (panel
a). The projected rises in ATOTP are in order of 20–30% in the southern areas of
ESA, while in most zones changes are about 10–20% or lower. Figures indicate
that the annual precipitation percentage changes show moderate shift compared to
the present conditions. The case for extreme precipitation (R95pTOT), in contrast,
shows for future projection an overall rise over 30% in most central and southern
ESA. Then, it is expected that under a scenario of great GHG emissions, the region
would undergo more extreme wet precipitation events than in the present climate.
Note that ESA is the only part of Argentina in which flooding risks due to Parana’s
runoffs are also projected to increase by the end of the century using GCMs (Saurral
et al. 2010; Hirabayashi et al. 2013). Moreover, more frequent and lasting fluvial
flooding events in the Paraná and Uruguay basins could be expected using regional
climate modeling (Camilloni et al. 2013). Thus, climate projections over ESA by
the end of the current century are favorable to increase the vulnerability of flooding,
regarding the physical aspect. This exerts a warning to be proactive in developing
strategies of adaptation and implementation of new mitigation policies.
Socio-demographic Factors
The climatic factors mentioned above are undoubtedly fundamental in explaining
the evolution of recent floods in ESA. However, the vulnerability of the population
to such natural hazards is in its essence a multi-causal phenomenon that is also
closely related to land use and population changes (Wisner et al. 2003). For instance,
unplanned urban sprawl into flood-prone areas, usually observed in less developed
countries such as Argentina, results in overall increased vulnerability to a given level
of hazard. Moreover, poor people are usually more likely to settle in flood-prone areas
because land prices tend to be cheaper (see Rabassa and Zoloa 2016, for evidence on
land markets and floods in ESA). Therefore, the welfare costs generated by floods
tend to fall disproportionately on these poor sectors of the population because they
lack access to reliable formal or informal social safety nets.
Another important factor in explaining overall increase in vulnerability to flooding
is the expansion of agricultural production. In ESA, this expansion was achieved at
the expenses of native forests and rangelands, especially in the northern lands. As
discussed in the previous sections, this process of deforestation due to land conversion
could have severely affected evapotranspiration given a certain level of precipitation
E. A. Agosta et al.
for ATOTP and R95pTOT using historical and RCP8.5 simulations, which represent
the most radical scenario concerning of global.
The historical ensemble means of ATOTP and annual R95pTOT over the baseline 1961–1990 are shown in Fig. 10, panels a and c, respectively. Their percentage
changes with respect to baseline, projected by the end of the current century (2075–
2099), are shown in panels b and d, respectively. Overall, the historical ensemble
means for both ATOTP (panel a) and R95pTOT (panel c) show similar spatial distribution and gradient from west to east and south to north. The percentage changes of
ATOTP show moderate change (panel b) compared to the present conditions (panel
a). The projected rises in ATOTP are in order of 20–30% in the southern areas of
ESA, while in most zones changes are about 10–20% or lower. Figures indicate
that the annual precipitation percentage changes show moderate shift compared to
the present conditions. The case for extreme precipitation (R95pTOT), in contrast,
shows for future projection an overall rise over 30% in most central and southern
ESA. Then, it is expected that under a scenario of great GHG emissions, the region
would undergo more extreme wet precipitation events than in the present climate.
Note that ESA is the only part of Argentina in which flooding risks due to Parana’s
runoffs are also projected to increase by the end of the century using GCMs (Saurral
et al. 2010; Hirabayashi et al. 2013). Moreover, more frequent and lasting fluvial
flooding events in the Paraná and Uruguay basins could be expected using regional
climate modeling (Camilloni et al. 2013). Thus, climate projections over ESA by
the end of the current century are favorable to increase the vulnerability of flooding,
regarding the physical aspect. This exerts a warning to be proactive in developing
strategies of adaptation and implementation of new mitigation policies.
Socio-demographic Factors
The climatic factors mentioned above are undoubtedly fundamental in explaining
the evolution of recent floods in ESA. However, the vulnerability of the population
to such natural hazards is in its essence a multi-causal phenomenon that is also
closely related to land use and population changes (Wisner et al. 2003). For instance,
unplanned urban sprawl into flood-prone areas, usually observed in less developed
countries such as Argentina, results in overall increased vulnerability to a given level
of hazard. Moreover, poor people are usually more likely to settle in flood-prone areas
because land prices tend to be cheaper (see Rabassa and Zoloa 2016, for evidence on
land markets and floods in ESA). Therefore, the welfare costs generated by floods
tend to fall disproportionately on these poor sectors of the population because they
lack access to reliable formal or informal social safety nets.
Another important factor in explaining overall increase in vulnerability to flooding
is the expansion of agricultural production. In ESA, this expansion was achieved at
the expenses of native forests and rangelands, especially in the northern lands. As
discussed in the previous sections, this process of deforestation due to land conversion
could have severely affected evapotranspiration given a certain level of precipitation