52
E. A. Agosta et al.
as measured by the long-term average of the MFM index, and the net migration rate
for each municipality in ESA, discriminated into non-GBA (panel a) and GBA (panel
b) municipalities. Net migration is the difference between the observed population
and the expected population, as calculated by INDEC, the National Statistical Office,
based on census data. Though population has increased in most localities, the net
migration rate has been negative in many municipalities in non-GBA areas. On
average, net migration in non-GBA and GBA municipalities has been −1.07% and
+4.91%, respectively. Note that the correlation between net migration and the MFM
index for non-GBA municipalities is −0.194 (significantly different from zero at
α=0.01), implying outmigration from more risky areas. In contrast, the correlation
for GBA municipalities is +0.207 (significantly different from zero at α=0.05),
suggesting population gains in more risky localities.
Although it would be quite impulsive to directly attribute a causal relationship
between flood risks and migration from correlation analysis, it is not possible to
disregard that flooding risks might affect migratory patterns. To our knowledge, no
other previous studies have analyzed the issue of migration and floods for ESA, and
the exploratory results in this section suggest that it might be an interesting line of
research, especially considering climate change and its impacts. The latter might
be relevant for the GBA subregion, since such a correlation structure could imply
an increase in the number of people exposed to flood hazards, given the projected
increased precipitation by the end of the twenty-first century (see Fig. 10, panel d).
Agricultural Expansion and Flood Risks
Besides people’s exposure to hazards, one of the main determinants of economic
losses due to flooding in ESA is agricultural activity. Every year, the Argentine
economy can be expected to lose about 0.15% of its GDP due to flood-related events.
While at a first glance, this could appear a minor amount, it adds up to a total annual
economic loss of around USD 700 m (Swiss Re 2016).
Agricultural expansion in the region, mostly due to the international demand of
soybean and the introduction of herbicide-resistant varieties, has been carefully documented (Viglizzo et al. 2011). The expansion has been at the expenses of native vegetation cover and other crops on already cultivated lands, but principally at expense of
the displacement of livestock production into marginal lands. This change in production activities might have an important effect on flood vulnerability (Nosetto et al.
2015).
In ESA, there are 174 municipalities with non-negligible agricultural activities
for the 1990s and the 2000s (note that there is no agricultural production in the
urbanized GBA subregion). On average, the percentage decadal change in net sown
area has increased by 18.05% in those municipalities (66 municipalities had negative
change in net sown area). Net sown area is the area which has been sown at least one
within any crop season. The massive land conversion into agricultural production
could further alter the risk of flooding by reducing soil absorption soon, as pointed
E. A. Agosta et al.
as measured by the long-term average of the MFM index, and the net migration rate
for each municipality in ESA, discriminated into non-GBA (panel a) and GBA (panel
b) municipalities. Net migration is the difference between the observed population
and the expected population, as calculated by INDEC, the National Statistical Office,
based on census data. Though population has increased in most localities, the net
migration rate has been negative in many municipalities in non-GBA areas. On
average, net migration in non-GBA and GBA municipalities has been −1.07% and
+4.91%, respectively. Note that the correlation between net migration and the MFM
index for non-GBA municipalities is −0.194 (significantly different from zero at
α=0.01), implying outmigration from more risky areas. In contrast, the correlation
for GBA municipalities is +0.207 (significantly different from zero at α=0.05),
suggesting population gains in more risky localities.
Although it would be quite impulsive to directly attribute a causal relationship
between flood risks and migration from correlation analysis, it is not possible to
disregard that flooding risks might affect migratory patterns. To our knowledge, no
other previous studies have analyzed the issue of migration and floods for ESA, and
the exploratory results in this section suggest that it might be an interesting line of
research, especially considering climate change and its impacts. The latter might
be relevant for the GBA subregion, since such a correlation structure could imply
an increase in the number of people exposed to flood hazards, given the projected
increased precipitation by the end of the twenty-first century (see Fig. 10, panel d).
Agricultural Expansion and Flood Risks
Besides people’s exposure to hazards, one of the main determinants of economic
losses due to flooding in ESA is agricultural activity. Every year, the Argentine
economy can be expected to lose about 0.15% of its GDP due to flood-related events.
While at a first glance, this could appear a minor amount, it adds up to a total annual
economic loss of around USD 700 m (Swiss Re 2016).
Agricultural expansion in the region, mostly due to the international demand of
soybean and the introduction of herbicide-resistant varieties, has been carefully documented (Viglizzo et al. 2011). The expansion has been at the expenses of native vegetation cover and other crops on already cultivated lands, but principally at expense of
the displacement of livestock production into marginal lands. This change in production activities might have an important effect on flood vulnerability (Nosetto et al.
2015).
In ESA, there are 174 municipalities with non-negligible agricultural activities
for the 1990s and the 2000s (note that there is no agricultural production in the
urbanized GBA subregion). On average, the percentage decadal change in net sown
area has increased by 18.05% in those municipalities (66 municipalities had negative
change in net sown area). Net sown area is the area which has been sown at least one
within any crop season. The massive land conversion into agricultural production
could further alter the risk of flooding by reducing soil absorption soon, as pointed