{"id":9956,"date":"2026-10-27T04:32:12","date_gmt":"2026-10-27T04:32:12","guid":{"rendered":"https:\/\/gerens.pe\/blog\/?p=9956"},"modified":"2026-10-27T04:32:12","modified_gmt":"2026-10-27T04:32:12","slug":"d-day-el-nino-and-the-danger-of-assuming-that-history-will-repeat-itself","status":"publish","type":"post","link":"https:\/\/gerens.pe\/blog\/d-day-el-nino-and-the-danger-of-assuming-that-history-will-repeat-itself\/","title":{"rendered":"D-Day, El Ni\u00f1o, and the Danger of Assuming That History Will Repeat Itself"},"content":{"rendered":"

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Presentation<\/strong><\/p>\n

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The G\u011aRENS Graduate School presents the article \u201cD-Day, El Ni\u00f1o, and the Danger of Assuming History Repeats Itself,\u201d written by Dr. Vinio Floris, Professor at G\u011aRENS and Director of our institution’s CEGAMA. It is a matter of great satisfaction and deep pride to highlight that Dr. Floris has recently been appointed as a Senior Fellow at Harvard University, an extraordinary recognition of his career.<\/strong><\/p>\n

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Dr. Floris’s article presents a profound reflection on the potential consequences of the 2026-2027 El Ni\u00f1o phenomenon, with a special focus on the impacts on Peru and Ecuador. Using the momentous meteorological decisions prior to D-Day in 1944 as an analogy, the author analyzes the danger of assuming that new climate events will replicate the exact patterns or damage of the past, given changing climate conditions, infrastructure, and population vulnerability. Furthermore, the text addresses the need to ground risk management and economic estimates in a rigorous scientific evaluation that integrates meteorology, climatology, hydrology, and hydraulics. Finally, the document sets forth a series of reflections aimed at improving preparedness, territorial planning, and adaptation to future emergencies. <\/strong>We invite you to read this interesting article.<\/strong><\/p>\n

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D-Day, El Ni\u00f1o, and the Danger of Assuming That History Will Repeat Itself<\/strong><\/h3>\n

Vinio Floris, PhD, PE, CSP, BCEE[1]<\/a><\/strong><\/p>\n

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In the movie Pressure<\/em>, British Chief Meteorological Officer Group Captain James Stagg clashes with his American counterpart, Lieutenant Colonel Irving P. Krick. At the heart of their disagreement is a fundamental question: Can patterns observed in the past reliably predict what will happen in the future?<\/em><\/p>\n

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The film dramatizes the extraordinary meteorological decisions behind D-Day (battle of Normandy), June 6, 1944, when the success of the largest amphibious invasion in history depended, in part, on identifying a narrow window of favorable weather. Allied commanders had to make a consequential decision under uncertainty, weighing competing forecasts with potentially enormous human and strategic consequences.<\/p>\n

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One lesson stands out: the past provides valuable evidence, but it does not guarantee<\/u> the future. Historical analogies can inform forecasts, but they become less reliable when the conditions underlying those analogies change. The D-Day experience demonstrates why scientific evidence, professional judgment, and a rigorous assessment of uncertainty must guide decisions especially when the stakes are high.<\/p>\n

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This excellent film deserves to be seen by scientists, engineers, policymakers, and leaders responsible for managing catastrophic risks. It also prompted me to reflect on the potential consequences of the 2026-2027 El Ni\u00f1o, particularly for Peru and Ecuador, as concerns grow about a potentially strong event in the Pacific. The challenge is not simply to anticipate the climate phenomenon itself, but to understand how its effects may translate into physical hazards, economic losses, and human suffering.<\/p>\n

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  1. El Ni\u00f1o’s history does not necessarily predict its future<\/strong><\/li>\n<\/ol>\n

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    Scientists have studied the El Ni\u00f1o\u2013Southern Oscillation (ENSO) for decades, building valuable knowledge from observations of previous events. However, assuming that a new event will reproduce the characteristics or consequences of a historical one can be misleading<\/u>.<\/p>\n

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    Each El Ni\u00f1o differs in its evolution, duration, geographical distribution of ocean warming, atmospheric response, and regional impacts. Even events of comparable magnitude can produce different rainfall patterns and consequences.<\/p>\n

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    Climate change adds another layer<\/u> of complexity. It is altering the background conditions of the atmosphere and oceans, including their temperatures and moisture-holding capacity. These changes can influence the consequences of extreme rainfall and heat, even though there is not yet sufficient evidence to conclude that climate change is increasing the frequency or intensity of El Ni\u00f1o events themselves.<\/p>\n

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    Historical comparisons remain essential, but they must account for these changing conditions. A sound assessment should consider not only whether a new event resembles those of 1982\u20131983, 1997\u20131998, or 2017, but also where the ocean is warming, how the atmosphere is responding, and how present-day environmental and socioeconomic conditions differ from those of the past.<\/p>\n

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    The critical question is not whether history will repeat itself, but which aspects of previous events remain relevant under current conditions.<\/p>\n

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      \n
    1. Sea surface temperature alone cannot tell us the full story<\/strong><\/li>\n<\/ol>\n

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      Projections of severe economic consequences deserve careful scrutiny when they are not supported by sufficiently detailed meteorological, climatological, and hydrological analysis.<\/p>\n

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      Sea surface temperature is a fundamental indicator of El Ni\u00f1o and is particularly important for understanding marine ecosystems, fisheries, and ocean-dependent economic activities. However, ocean temperature anomalies alone cannot establish how much rainfall a particular watershed will receive or whether a community will experience destructive flooding. Assessing these risks requires a sequence of scientific analyses.<\/p>\n

      \n

      First, oceanic and atmospheric observations, together with climate models, help characterize the evolving phenomenon and its potential regional influence. Second, meteorological forecasts estimate the likely timing, location, duration, and intensity of precipitation. Third, hydrological models translate rainfall into potential runoff, river discharge, and flood conditions.<\/p>\n

      \n

      This third step is particularly important. The relationship between rainfall and runoff depends on antecedent soil moisture, infiltration capacity, topography, catchment size and characteristics, vegetation, land use, and drainage conditions. In urban areas, impervious surfaces and inadequate drainage can accelerate runoff and increase flood peaks. In steep or unstable terrain, intense rainfall can trigger flash floods, debris flows, and landslides.<\/p>\n

      \n

      The same rainfall total can therefore produce substantially different consequences in different watersheds or even in the same watershed under different antecedent conditions.<\/p>\n

      \n

      Reliable flood-risk assessment should integrate rainfall intensity and duration, the spatial distribution of precipitation, catchment response, riverine hydraulics, floodplain exposure, and the performance of drainage and protective infrastructure. Where appropriate, it should also account for sediment transport, mudslides, channel obstructions, and the possibility of infrastructure failure.<\/p>\n

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      In other words, ocean conditions help characterize the climate phenomenon; meteorology estimates the atmospheric hazard; hydrology and hydraulics help determine how that hazard translates into flooding and other physical impacts. Exposure, vulnerability, and infrastructure resilience then help determine the consequences for people, communities, and the economy. No single indicator can substitute for this chain of analysis.<\/p>\n

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      1. Peru today is not the Peru of previous major El Ni\u00f1o events<\/strong><\/li>\n<\/ol>\n

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        Since the major El Ni\u00f1o events of past decades, human activities have profoundly transformed Peru’s landscapes, cities, and infrastructure. Urban expansion, deforestation in some areas, changes in land use, and construction in flood-prone locations have altered exposure to natural hazards. Population growth and the expansion of economic activity have also increased the value of assets potentially at risk.<\/p>\n

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        Inadequate territorial planning, weak enforcement of land-use regulations, poorly maintained drainage systems, and infrastructure designed without sufficient consideration of extreme events can amplify the consequences of intense rainfall.<\/p>\n

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        Construction in riverbeds and floodplains is especially problematic. So are undersized culverts, drainage channels obstructed by sediment or waste, and roads or other structures that redirect water toward vulnerable settlements. In steep catchments, the interaction of intense precipitation with unstable slopes can create additional hazards.<\/p>\n

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        These conditions matter because disaster risk is not determined by the natural hazard alone. It also depends on the people and assets exposed to that hazard, their vulnerability, and their capacity to prepare, respond, and recover.<\/p>\n

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        A useful formula de describes risk is:<\/p>\n

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        Disaster risk = hazard \u00d7 exposure \u00d7 vulnerability<\/strong><\/p>\n

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        Source: United Nations Office for Disaster Risk reduction<\/a> (UNDRR)<\/p>\n

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        This is an organizing framework rather than a universal numerical equation.<\/p>\n

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        The distinction has important policy implications. Even if the next El Ni\u00f1o (classified as a Super El Ni\u00f1o) produces rainfall comparable to that of a previous event, the resulting losses could be greater if more people and infrastructure occupy exposed areas or if drainage and protective systems have deteriorated. Conversely, better land-use planning, early warning, maintenance, and emergency preparedness can reduce losses even when the hazard cannot be prevented.<\/p>\n

        \n

        The essential question is not simply whether the next El Ni\u00f1o will be stronger or weaker than previous events. It is whether Peru’s communities, infrastructure, and institutions are prepared for the conditions that may actually occur.<\/p>\n

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          \n
        1. El Ni\u00f1o and El Ni\u00f1o Costero: Related phenomena, different dynamics<\/strong><\/li>\n<\/ol>\n

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          Peru’s devastating experience in 2017 illustrates why it is essential to distinguish between the broader El Ni\u00f1o\u2013Southern Oscillation (ENSO) phenomenon and El Ni\u00f1o Costero.<\/p>\n

          \n

          El Ni\u00f1o Costero is a climate event characterized by sustained anomalous warming of sea surface temperatures in the far eastern tropical Pacific, particularly off the coasts of Peru and Ecuador. In Peru, the event is monitored using the Coastal El Ni\u00f1o Index (ICEN), which is based on three-month running averages of sea surface temperature anomalies in the Ni\u00f1o 1+2 region. Under the operational definition used by Peru’s ENFEN, an event is identified when the index indicates warm conditions for at least three consecutive months.<\/p>\n

          \n

          Unlike the broader ENSO phenomenon, which involves coupled ocean\u2013atmosphere changes across the tropical Pacific and can influence climate patterns around the world, El Ni\u00f1o Costero is associated with warming concentrated in the far eastern Pacific. Its effects can be particularly severe along the arid coasts of Peru and Ecuador, where anomalously warm ocean waters can promote atmospheric convection and intense rainfall.<\/p>\n

          \n

          The March 2017 disaster in Peru provides a striking example. The coastal warming intensified rapidly in January 2017, even as conditions in the central Pacific remained broadly neutral. The warming helped activate an unusually intense band of atmospheric convection near the Peruvian coast, contributing to exceptionally heavy rainfall in northern Peru. The event caused extensive flooding, loss of life, and severe damage to roads and other infrastructure.<\/p>\n

          \n

          The development of the 2017 event also illustrates the importance of ocean-atmosphere interactions. Changes in coastal and equatorial winds, ocean circulation, and the movement of warm surface waters contributed to the anomalous warming. The resulting rainfall, however, was not simply a direct consequence of higher sea surface temperatures or increased evaporation. Atmospheric circulation, moisture transport, and the organization of convective systems were also critical to determining where and how intensely it rained.<\/p>\n

          \n

          This distinction matters. El Ni\u00f1o Costero and the broader ENSO phenomenon can occur together, but they do not necessarily develop in parallel or produce identical impacts. The 2017 event demonstrated that severe coastal warming and destructive rainfall can develop even when the central Pacific does not exhibit a conventional El Ni\u00f1o pattern.<\/p>\n

          \n

          Consequently, the magnitude of warming in one region of the Pacific cannot, by itself, establish the expected rainfall or flood severity in a particular location. Assessments must examine the geographical distribution and evolution of ocean temperatures, atmospheric circulation, precipitation forecasts, and local watershed conditions.<\/p>\n

          \n

          Confusing El Ni\u00f1o Costero with the broader ENSO phenomenon can lead to misleading historical comparisons and inadequate risk assessments. Both require rigorous observation and forecasting, but their potential hydrological consequences must be evaluated using regionally appropriate meteorological, hydrological, and hydraulic analyses.<\/p>\n

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          1. Science and scientists must come first<\/strong><\/li>\n<\/ol>\n

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            A positive aspect of this discussion is that Peru, other South American countries, and many institutions in the United States, Australia, Europe and other nations have highly qualified meteorologists, climatologists, and hydrologists working to understand these complex phenomena and improve forecasts. Their expertise is indispensable, and their contributions deserve recognition.<\/p>\n

            \n

            Economists and economic forecasters also play a key role in estimating potential losses, evaluating the effects on economic activity, and identifying the resources needed for recovery and adaptation. Their work is essential, but the reliability of their conclusions depends, in part, on the quality of the physical-science information incorporated into their analyses.<\/p>\n

            \n

            Historical economic losses can provide useful reference points. However, extrapolating past losses into the future without accounting for current climate conditions, updated hazard assessments, changes in exposure, and infrastructure vulnerability can produce misleading estimates.<\/p>\n

            \n

            Climate and hydrological systems are nonlinear. Rainfall, runoff, and flood damage do not necessarily increase in direct proportion to one another. A relatively small increase in rainfall intensity can, under certain conditions, exceed a drainage system’s capacity or trigger a rapid rise in river discharge. Once a critical threshold is crossed, consequences can escalate disproportionately.<\/p>\n

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            Economic damage can also be nonlinear. Flooding that closes a major transportation corridor, interrupts electricity or water supplies, or disrupts a critical industrial facility can generate losses well beyond the value of the assets directly damaged.<\/p>\n

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            For these reasons, economic assessments should not rely exclusively on historical averages or simple extrapolations. They should incorporate physically plausible scenarios, uncertainty ranges, and, where appropriate, probabilistic estimates of hazard and loss. Sensitivity analysis and stress testing can help decision-makers understand how results change under different rainfall, runoff, infrastructure-failure, and exposure assumptions.<\/p>\n

            \n

            Let us be clear: Sound decisions begin with the sciences that explain the phenomena and their potential consequences. <\/strong>Meteorology, climatology, hydrology, and hydraulic engineering must provide the scientific foundation for economic assessments, infrastructure planning, public policy, and investment decisions. Economics helps us understand the consequences for society; the physical sciences help us characterize the processes that drive those consequences. Risk analysis connects the two.<\/p>\n

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            The objective is not to diminish the value of economic forecasting. It is to strengthen it through interdisciplinary collaboration, transparent assumptions, and evidence-based analysis.<\/p>\n

            \n

            From forecasting to preparedness<\/strong><\/p>\n

            \n

            The lesson of D-Day is not that scientists can predict the future with certainty. It is that rigorous analysis, continuous observation, and the responsible communication of uncertainty can make the difference between a sound decision and a catastrophic mistake.<\/p>\n

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            For Peru, Ecuador, and other vulnerable regions, preparedness should connect seasonal climate outlooks with updated meteorological forecasts, hydrological and hydraulic modeling, flood-risk mapping, infrastructure assessments, land-use planning, and emergency response.<\/p>\n

            \n

            These activities should be supported by reliable observation networks, accessible scientific data, coordination among responsible institutions, and clear communication with communities. Forecasts must also be translated into practical decisions: where to clear drainage channels, which bridges or roads require inspection, where temporary evacuations may be necessary, and how to protect essential services and vulnerable populations.<\/p>\n

            \n

            Because forecasts have uncertainty, planning should consider multiple plausible scenarios rather than depend on a single prediction. Monitoring and decision thresholds should be updated as new information becomes available. This approach allows governments and infrastructure operators to act early without assuming that the worst-case scenario is inevitable.<\/p>\n

            \n

            We cannot control El Ni\u00f1o. But we can improve our ability to anticipate its consequences and reduce the risks created by our own decisions.<\/p>\n

            \n

            Are we preparing for the El Ni\u00f1o we may actually face or for the one we remember?<\/p>\n

            [1]<\/a> Senior Fellow, Harvard University. Professor, GERENS Postgraduate School.<\/p>\n

            Disclaimer<\/strong>: The views expressed are solely those of Vinio Floris and do not necessarily reflect those of any affiliated institution or organization. The author alone is responsible for this article\u2019s content and conclusions.<\/p>\n","protected":false},"excerpt":{"rendered":"

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