LIMA — Peruvian historian Javier Puente's latest research includes some very interesting maps. The first (and most extensive) covers the area affected by drought as a result of the El Niño weather phenomenon between 1982 and 1983 (when it was unusually intense). The second, relying on data from Peru's Truth and Reconciliation Committee, shows the areas that saw the highest incidence of political violence during the state's war against the Maoist insurgent group Shining Path.

The two maps perfectly overlap. A third map shows where the Shining Path committed its worst massacres of civilians. And that too lines up with the others, as all but one of those atrocities were committed inside the drought-hit zone, in the central and southern parts of the Peruvian Andes.

This isn't, of course, the whole story. In the early 1980s, El Niño also produced floods that were particularly severe on Peru's northern coast — without any corresponding increase in political violence. To explain this difference, it's worth citing NYU professor Alastair Smith, who found that the variable that best explains the proportion of deaths from natural disasters is income per head. Higher income means having more resources to respond to disasters. It's also tied to better access to healthcare or security, which contribute both to preventing and palliating disasters.

Low income levels make natural disasters more deadly.

The same can be said about different regions in a country: Peru's northern coast has and always had, since the republic began, higher per capita incomes than the southern mountain areas. Even in the north, disaster response continues to be deficient. But it's even worse in the south. Just think about the damage done every year in the south by winter frosts, which are both natural and predictable.

Paradoxically, research like that done by University of Oxford professor Paul Collier shows that per capita income is also a crucial variable in estimating the probability of armed conflict happening in a country. Violence of that kind is considerably more likely to happen in nations with very low per capita income levels. Using that same logic to compare regions within a given nation, it would seem — in the case of 1980s Peru — that there were perverse synergies in the southern zones.

For one thing, low per capita income levels make natural disasters more deadly. And those disasters, in turn, drag income levels down further still (especially in rural areas, since disasters are particularly damaging to farming activities). At the same time, low per capita income levels raise the likelihood of armed conflicts, which again, push down income levels, as studies commissioned by the World Bank have shown. Little wonder then that of the 39 countries involved in civil wars during the year 2000-2011, the vast majority (90%) had also experienced internal conflicts in the preceding three decades.

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