The conceptual heart of the study lies in distinguishing two related but distinct phenomena. Compound risks emerge when multiple climatic drivers, hazards, or vulnerabilities interact to produce impacts greater than any factor alone would suggest, whether simultaneously, as when heat and drought strike together, or sequentially, as when prolonged drought is followed by intense rainfall on desiccated, impermeable ground. Cascading risks describe something different: the propagation of an initial shock through interconnected systems, so that a meteorological event becomes a crisis of electricity, water, telecommunications, housing, mobility, and public health. A heatwave strains the electricity grid at precisely the moment demand for cooling peaks; a power outage then disables water pumping, refrigeration, traffic control, and hospital systems. The authors emphasize that these terms are not synonyms, and that conflating them obscures the specific pathways through which urban crises unfold.

Underpinning the analysis is the idea that cities are not passive recipients of hazards but dense socio-technical systems in which physical infrastructure, economic activity, ecological conditions, social vulnerability, and institutional decision-making are deeply intertwined. Electricity, water supply, drainage, transport, telecommunications, food distribution, and emergency response are so interdependent that a disruption in one domain can propagate across the others, transforming a localized event into a systemic urban crisis. Crucially, the authors note, infrastructure is not merely technical. It is shaped by political choices, investment patterns, maintenance gaps, institutional fragmentation, and unequal territorial development, which means that resilience is as much a governance, finance, and equity challenge as an engineering one.

To build the evidence base, the researchers conducted a targeted comparative scoping review combined with qualitative policy-document analysis, covering literature published primarily between January 2020 and June 2026. Searches in Scopus, Web of Science, and Google Scholar, supplemented by policy repositories and conducted in both English and Spanish, yielded a final corpus of 81 sources: 54 academic publications and 27 policy, governmental, or institutional documents. Each source was coded across eight dimensions, including hazard profile, compound interaction, cascading pathway, social amplification, governance challenge, funding challenge, and policy response. The urban cases spanned New Orleans and Los Angeles in the United States; Toronto, Vancouver, Halifax, Calgary, and Edmonton in Canada; and Mexico City, Monterrey, Acapulco, and Veracruz–Boca del Río in Mexico, selected to capture contrasting combinations of coastal storms, heat, drought, flooding, sea-level rise, and institutional capacity.

The United States cases reveal the tension between strong subnational innovation and unstable federal climate policy. New Orleans illustrates how a coastal hazard becomes a systemic urban crisis: Hurricane Katrina combined storm surge and flooding with levee failure, electricity and communications disruption, constrained emergency access, housing loss, prolonged displacement, and racialized recovery outcomes. The city now possesses a relatively mature hazard-mitigation architecture linking its Hazard Mitigation Office, Office of Sustainability, NOLA Ready, and the Sewerage and Water Board, yet institutional coordination and equitable implementation remain continuing challenges. Los Angeles, meanwhile, faces interacting heat, drought, wildfire and smoke, flooding, and electricity stress, and benefits from California’s adaptation strategy and novel financing mechanisms such as climate-resilience districts under Senate Bill 852. But responsibility for heat, wildfire, water, drainage, energy, and housing remains divided among agencies, and the availability of state and federal funds varies across programs and political cycles.

Canada presents a different profile: a relatively advanced national adaptation framework paired with a persistent urban implementation gap. The National Adaptation Strategy establishes shared goals for disaster resilience, health, nature, infrastructure, and the economy, while provinces retain major responsibilities for municipalities, land use, and emergency management. Canada’s National Issues Report concludes that local governments are moving from planning toward implementation, but that action is not keeping pace with present and projected risks. Toronto’s climate-risk assessment connects heat, flooding, wildfire smoke, infrastructure, and vulnerable populations; Vancouver’s adaptation strategy integrates sea-level rise and coastal exposure; Halifax, Calgary, and Edmonton each maintain formal strategies. The recurring deficit, the review finds, is not the absence of plans but the incomplete integration of municipal instruments with infrastructure ownership, provincial authority, long-term finance, Indigenous governance, and operational performance indicators.

Mexico’s cases expose how cascading risks intensify under uneven urbanization, water insecurity, infrastructure deficits, informality, and fragmented metropolitan governance. In the Mexico City Metropolitan Area, drought and flooding are interconnected rather than opposing risks: low reservoir levels in the Cutzamala system, groundwater depletion, subsidence, leakage, and unequal household access can convert climatic drought into a wider service and governance crisis, while intense rainfall overwhelms drainage and mobility systems. Monterrey’s 2022 water crisis combined prolonged drought, reservoir depletion, infrastructure deficiencies, and unequal access. Acapulco offers perhaps the most dramatic illustration: Hurricane Otis in 2023, a rapidly intensifying cyclone, damaged housing, hotels, roads, electricity, water, telecommunications, and livelihoods, turning a single storm into an urban economic and social crisis. The Veracruz–Boca del Río conurbation demonstrates horizontal fragmentation, where the ecological and infrastructure system is metropolitan but planning authority and budgets remain divided between two municipalities and the state.

From the cross-case comparison, the authors distill three types of governance deficit. A vertical deficit occurs when national or state commitments are not matched by predictable municipal finance, authority, or implementation support, a pattern visible in Canadian municipal dependence on federal programs, U.S. dependence on shifting federal funding, and Mexican municipal dependence on state institutions. A horizontal deficit arises when sectoral agencies or adjacent municipalities manage interconnected systems separately, as in Los Angeles infrastructure governance, Mexico City’s metropolitan water system, and Veracruz–Boca del Río. An operational deficit emerges when plans or risk atlases identify hazards but remain weakly connected to budgets, maintenance, enforcement, monitoring, or social protection, with Acapulco cited as a clear example. A study of twenty North American city governments cited in the review similarly found that resilience governance frequently remains divided across agencies and sectors even when climate risks are cross-sectoral.

The review also highlights a subtler danger: strategies intended to enhance resilience to one event may inadvertently reduce resilience to another concurrent hazard. Prospective analysis, infrastructure stress testing, and scenario planning can help identify and minimize such unintended consequences, particularly as research projects increases in the frequency and duration of compound dry-hot extremes across major U.S. cities under the combined effects of climate change and urban development. Community-centered approaches and the co-design of problem-solving processes can strengthen adaptation programs, while interagency coordination and transdisciplinary research are needed to address effects that move across sectors and reduce siloed management. The authors caution that their findings should be interpreted as an analytically structured synthesis rather than a statistical ranking of urban performance, given the targeted nature of the review and the uneven evidence base across countries.

The ultimate message is a call to move from isolated adaptation measures toward integrated risk governance. Cities are exposed not only to individual hazards but to hazards that interact with one another and with the infrastructure, social, and governance systems that sustain urban life. A heatwave can become an energy and public-health crisis; a drought can become a water, economic, and governance crisis; a hurricane can become a housing, telecommunications, transport, energy, and social-protection crisis. Without prospective scenario planning, infrastructure stress testing, stable resilience financing, intersectoral metropolitan coordination, and equity-centered infrastructure planning, the authors warn, cities may remain trapped in reactive cycles of emergency response and reconstruction rather than achieving sustained risk reduction. The future of urban resilience, the review suggests, will depend on whether cities can govern the relationships among infrastructure, inequality, finance, and climate uncertainty in coordinated and equitable ways.

Subject of Research: Compound and cascading climate risks in urban infrastructure governance and resilience in North American cities

Article Title: Compound and cascading climate risks in urban infrastructure governance and resilience across North America

Article References: Lucatello, S., & Henríquez, B. P. (2026). Compound and cascading climate risks in urban infrastructure governance and resilience across North America. Discover Cities, 3(1), Article 201. https://doi.org/10.1007/s44327-026-00374-1

Image Credits: AI Generated

DOI: 10.1007/s44327-026-00374-1

Keywords: compound climate risk, cascading failures, urban resilience, critical infrastructure, climate adaptation, governance, North America, flooding, extreme heat, drought, hurricanes, social vulnerability

The researchers drew on daily rainfall estimates from the CHIRPS satellite-based dataset and monthly soil moisture from the FLDAS Noah land-surface model, both averaged across the full administrative boundary of Gedaref State for the period 1982 to 2020. They supplemented these with annual sorghum and sesame records from the Gedaref State Ministry of Production and Economic Resources and the Mechanized Farming Corporation. Before anything else, the team checked how well the satellite rainfall product matched the available ground truth. Against a monthly station archive, CHIRPS showed a moderate seasonal correlation of 0.625, but agreement in absolute totals was limited, with a bias of minus 77.5 millimetres and a root mean square error of 130 millimetres. The authors attribute part of this discrepancy to the difference in spatial support: the station represents a single point in Gedaref town, while the satellite series averages across the entire state, including drier northern localities.

From the daily rainfall record, the researchers calculated four indicators designed to capture the main forms of within-season rainfall stress. The first was the April-to-November rainfall deficit, representing inadequate seasonal water supply. The second was the maximum number of consecutive dry days during the core June-to-September rainy period, a measure of the longest interruption in wetting. The third was onset delay, defined as the first date on or after 1 May when rainfall accumulated over three consecutive days reached 20 millimetres. The fourth was the share of seasonal rainfall delivered by the five wettest days, which captures how concentrated a season’s water supply is in a handful of violent storms. Across the record, these variables revealed striking variability: onset dates ranged from day 135 to day 240 of the year, maximum dry spells ranged from 2 to 13 days, and the five wettest days contributed between 10.2 and 21 percent of seasonal rainfall.

These four components were then combined into a single score, the Daily Rainfall-Structure Risk Index, or DRSRI, using principal component analysis. The analysis retained one component explaining 60.4 percent of the standardised variance, with coefficients of similar magnitude for all four variables, roughly 26, 25, 23 and 25 percent of the total weighting. Bootstrap resampling confirmed that no coefficient collapsed towards zero. Notably, an equal-weight version of the index correlated with the PCA version at 0.9997, meaning the sophisticated weighting made almost no practical difference to the annual ranking of risk. The index itself, however, turned out to be a powerful indicator of surface drying: higher DRSRI values coincided with lower modelled surface soil moisture anomalies in the top 10 centimetres of soil, with a correlation of minus 0.776 that was highly significant.

Yet the story took an unexpected turn when the researchers tested whether the index could actually predict soil moisture better than seasonal rainfall alone. Using a rolling-origin evaluation, in which models were trained on data from 1982 to 1996 and then progressively refitted as each new year arrived, the four rainfall-structure variables produced only a marginal and statistically unsupported improvement over seasonal rainfall, with root mean square errors of 0.544 versus 0.554 and a p-value of 0.739. The DRSRI alone performed worse than seasonal rainfall, with an RMSE of 0.681. The authors are candid about this result: the index is not a better predictor, but a better diagnostic. It tells you whether an unfavourable season was driven by low rainfall, late onset, a long dry spell, or concentrated storms, information that a single seasonal total cannot provide.

The agricultural analysis revealed perhaps the most consequential finding of the study. The clearest association was not with crop yields, as one might expect, but with the sorghum harvested-area ratio, the percentage of planted land reported as remaining productive through the season. This ratio was negatively correlated with DRSRI at minus 0.448 and positively correlated with seasonal rainfall at 0.440, both significant after false-discovery-rate correction. In contrast, no yield association for either sorghum or sesame remained statistically significant after multiple-testing correction. This distinction matters because yield measures output only from land recorded as productive, while the harvested-area ratio reflects how much planted land survived the season at all. In years with poor rainfall structure, farmers apparently lost a larger share of their planted area entirely.

The researchers also identified eight compound-risk years, 1984, 1990, 1998, 2001, 2004, 2009, 2013 and 2015, in which at least three of the four adverse rainfall conditions occurred simultaneously. In these years, modelled surface soil moisture anomalies averaged minus 0.970 standardised units compared with 0.250 in other years, and the sorghum harvested-area ratio anomaly averaged minus 0.956 versus 0.247. Both differences were highly significant. However, the classification proved sensitive to the thresholds used, with the exact set of flagged years changing under alternative percentile rules, even though the direction of the response remained stable. The authors frame this as an exploratory, impact-oriented classification rather than a formal definition of a multivariate climate extreme.

Two further findings complicate any simple narrative of worsening drought. First, a structural break detected after 1996 split the sorghum harvested-area record: the DRSRI association was strong before the break at minus 0.688 but weakened to minus 0.329 afterwards, while the seasonal rainfall association strengthened. Second, trend analysis after prewhitening and false-discovery-rate correction found no significant long-term change in any rainfall indicator between 1982 and 2020, yet the sorghum harvested-area ratio declined by about 9.2 percentage points per decade. This divergence suggests that the long-term deterioration in reported productive area was driven by factors other than rainfall, likely including the documented expansion of mechanised cultivation into more marginal clay plains, land degradation, and management or reporting changes.

The study is careful about its limits, and these caveats are instructive for anyone hoping to apply the approach elsewhere. The FLDAS soil moisture is modelled, not measured, and because CHIRPS rainfall contributes to the forcing of the FLDAS Noah model, the rainfall-moisture relationship represents internal consistency rather than independent validation. The Noah model also does not represent the cracking and preferential flow characteristic of the Vertisol clay soils that dominate Gedaref, adding further uncertainty. The state-wide averaging smooths local convective storms, meaning a wet day in the regional average does not guarantee rain on any particular field. The crop records, meanwhile, are annual administrative statistics lacking information on sowing dates, varieties, fertiliser use, pests, labour, or finance, all of which shape yields independently of rainfall.

For all these limitations, the work offers a practical template for drought monitoring in data-scarce drylands. The DRSRI can serve as a compact annual screening indicator, while its four components pinpoint the specific rainfall constraint operating in any given season. The authors suggest that early-season flags for delayed onset or extended dry spells could be overlaid with cropland and vegetation maps to direct field inspection where it is most needed. Future work, they argue, should move to pixel-level rainfall analysis within mapped cropland, compare satellite products against daily station observations, and incorporate independent soil moisture measurements. In a region where millions depend on rainfed sorghum and sesame, knowing not just how much rain fell but how it fell may prove the difference between anticipation and surprise.

Subject of Research: Within-season rainfall structure, modelled surface soil moisture and agricultural response in rainfed farming systems of eastern Sudan

Article Title: Rainfall structure and modelled surface soil moisture in relation to agricultural response in rainfed lands of eastern Sudan

Article References: Abaker, M., & Elfaki, J. (2026). Rainfall structure and modelled surface soil moisture in relation to agricultural response in rainfed lands of eastern Sudan. Discover Soil, 3(1), Article 181. https://doi.org/10.1007/s44378-026-00343-5

Image Credits: AI Generated

DOI: 10.1007/s44378-026-00343-5

Keywords: rainfall structure, soil moisture, rainfed agriculture, sorghum, sesame, drought, CHIRPS, FLDAS, Sudan, Gedaref, dry spells, compound climate risk