The problem the authors set out to solve is what decision scientists call deep uncertainty: a situation in which we cannot know which conceptual model describes the system, which probabilities represent the uncertainty, or even how to value the outcomes. Traditional hydraulic engineering leans heavily on the concept of the return period — the average interval between events of a given magnitude, such as a once-in-a-century storm surge. But that framework quietly assumes the climate is stationary, meaning its statistical behavior does not change over time. In the Anthropocene, that assumption has collapsed. As global warming reshapes storm tracks, sea levels and river discharges, new and unseen extremes are continuously being added to the record, and the small probabilities attached to rare events carry large relative errors because they demand sample sizes no observational record can supply.

Recent history offers vivid illustrations of the gap between normal and extreme widening. Northwestern Europe suffered severe drought as river discharges plummeted, mass coral bleaching has swept tropical reefs with devastating frequency, and Australia’s 2019–2020 Black Summer produced exceptionally large forest fires. Each event strained systems that had been optimized against a predicted or extrapolated future. The Delft researchers argue that optimization against a single forecast is precisely the wrong strategy when the forecast itself is the weakest link.

Nature, by contrast, never optimizes for a predicted future. Natural systems persist because they contain diverse sets of species that thrive under different conditions, adapt as those conditions shift, and remain robust to short-term fluctuations. The authors propose projecting the three classic dimensions of an engineering problem — forcing, time, and performance — onto three new axes in the output space: diversity, adaptability, and robustness. This is the crucial conceptual move of DARE. Rather than trying to pin down the uncertain inputs, such as future offshore wave heights, engineers should design systems whose outputs, such as wave runup on the shore, are insensitive to whatever the inputs turn out to be. The authors frame this as a step beyond the well-known shift from fighting against nature to building with nature: the next step is building like nature, emulating nature’s principles rather than merely its components.

The first axis, diversity, draws on the ecological concept of response diversity. Ecosystems survive shocks because different species can perform the same function under different conditions — a built-in redundancy. In one classic example, plankton species with differing tolerances to acidity maintained high biomass even as waters acidified, because whichever species could cope took over the functional role. Translated to engineering, this means assembling a diverse portfolio of solutions to a single task. For coastal flood defense, that portfolio could span the entire cross-shore profile: dikes and dunes at the coastline itself, and vegetated foreshores such as mangroves and marshes, living breakwaters, and wide beaches in the nearshore zone that dampen wave energy before it ever reaches the harder defenses behind them.

The second axis, adaptability, addresses change over both long and short timescales. Ecosystems adapt within species — corals with different historical temperature exposure show different thermal tolerances — and between species, as plant communities in the Himalaya shift composition under warming. In engineering, adaptability covers self-accommodating solutions such as dunes, which partially erode during storms but recover their sediment during calm periods and can even grow with sea level rise given sufficient sand supply, alongside adaptive strategies that keep room to change course as new information arrives. The authors also flag a subtlety: some solutions excel at extremes but cause unwanted side effects during normal conditions, as with storm surge barriers that alter estuarine mixing. Adaptability means designing so these trade-offs can be managed dynamically rather than locked in at construction.

The third axis, robustness, is defined as reducing the variability of outcomes regardless of environmental conditions. Natural systems absorb or dampen environmental fluctuations without dramatically altering their functions, up to a limit — climate tipping points being the stark boundary case. In engineering terms, robustness means that unknown uncertainties in future forcing are only partially translated into performance. The theoretical upper bound here is antifragility, a concept borrowed from Nassim Taleb: systems that actually benefit from stress, as some ecosystems appear to do when pre-stressing reduces damage from subsequent events. But because most engineering systems have hard performance ceilings, the authors note that non-fragile, robust systems are realistically the highest attainable outcome.

To demonstrate the framework, the authors apply DARE to two hydraulic engineering challenges. The first is coastal flooding, a threat to the roughly forty percent of humanity living within 100 kilometers of the coast. For reef-lined coasts, the physics is instructive: a long reef flat and high reef friction reduce wave runup, and as reef width increases, runup not only shrinks but becomes less variable — a textbook robustness property. Corals add adaptability, since reefs can grow with sea level rise and acclimatize to changing conditions, and native corals show far less bleaching under thermal stress than transplanted ones from different thermal environments. Even foredune blowouts, the gaps that open in the front line of dune defenses, contribute: by enhancing beach-dune interaction, they increase back-dune resilience against sea level rise, making the system as a whole more robust.

The second example is estuarine salt intrusion, which threatens the freshwater supplies of delta cities. Analysis of estuarine characteristics shows that low salt intrusion risk can be reached via multiple routes — large river discharge, a small cross-section, or a damping or amplifying tide — and pursuing several routes at once reduces reliance on any single one. A robust measure is enforcing a minimum channel depth, since shallower estuaries show reduced variability in intrusion. An adaptive measure is the temporary construction of a submerged earthen sill during droughts to halt the landward migration of the salt wedge, a contingency deployed only when conditions demand it, since it may hinder shipping under normal conditions. In a managed delta such as the Rhine-Meuse, water managers could combine controlled discharge, minimum depths, temporary sills, relocated water intakes and expanded storage into a diverse, adaptive, robust solution set.

The authors are candid about the limits of their proposal. DARE does not eliminate the need for data and models; it relocates that need from future forcing to system response, and characterizing a system’s response is far from trivial — a barrier that open datasets and models can help lower. Nor should engineers blindly copy nature, since coral reefs are bleaching worldwide and dunes depend on adequate sediment supply. Return periods retain regulatory value and need not be abandoned, the authors argue; what deserves reconsideration is the practice of optimizing a design against a single predicted future. What DARE offers, ultimately, is a conceptual toolkit: build in redundancy, keep room to adapt, and smooth out the performance of your system — so that whether the future brings what we expect or something no one saw coming, the shoreline holds.

Subject of Research: A biomimetic engineering framework for designing coastal and estuarine infrastructure under deep climate uncertainty

Article Title: DARE to proactively react to unknown uncertainties in the Anthropocene

Article References: Hendrickx, G. G., Pearson, S. G., Antolínez, J. A. A., & Aarninkhof, S. G. J. (2026). DARE to proactively react to unknown uncertainties in the Anthropocene. Frontiers in Marine Science, 13, Article 1880714. https://doi.org/10.3389/fmars.2026.1880714

Image Credits: AI Generated

DOI: 10.3389/fmars.2026.1880714

Keywords: hydraulic engineering, climate adaptation, deep uncertainty, coastal flooding, salt intrusion, coral reefs, resilience, nature-based solutions, biomimetics, sea level rise, return period, Anthropocene