Thursday 25th September 2025
Spatio-Temporal Scales and Socio-Economic Perspectives
Session 1: Cross-Scale Modelling of Physical–Ecological Interactions in Tropical Coastal Systems
This session examines how physical and ecological processes interact across scales at the tropical land–sea interface. It highlights modelling approaches that integrate extreme weather, hydrodynamics, biogeochemistry and ecological response, spanning groundwater and nutrient fluxes, sediment and salinity dynamics, and vegetation–climate feedbacks under anthropogenic and climatic pressures. Emphasis is placed on modular, cross-scale integration frameworks that enable realistic, process-based predictions of ecosystem states and indicators. The session links empirical observations (including remote sensing) to model development in under-represented tropical regions and defines transferable validation metrics and decision-relevant benchmarks. Guiding question: How can we connect large-scale atmospheric and terrestrial forcing to coastal and ecological outcomes, and what approaches are most transferable across regions?
Chair: Nils Moosdorf (ZMT)
09:00–09:30 – Keynote: Erma Yulihastin (BRIN, Indonesia) Ibnu Fathrio, Albertus Sulaiman, Mochamad Furqon Azis Ismail, Dwiyoga Nugroho, Rahaden Bagas Hatmaja, and Ginaldi Ari Nugroho
Assessment of Extreme Weather Events in the Changing Climate over the Indonesia Maritime Continent
Global warming contributed to severe weather events by increasing and intensifying worldwide occurrences. Recent studies revealed that 71% of extreme weather events are related to human-caused climate change. Hence, 56% of heavy rainfall or flooding events studied concluded that human activity influenced the severity of the events. Since the Indonesian Maritime Continent (IMC) comprises thousands of islands with complex topography surrounded by seas and has the 3rd longest coastline, this region experienced island-based, highly concentrated precipitation. The IMC also affects global climate through multiscale interaction from diurnal to interannual timescale due to ocean-atmosphere interaction. The variability of sea surface temperature in sub-daily timescale was proven to generate excessive rainfall, thus triggering several extreme weather events from micro-to- large scales with devastating impacts over several islands during transition-to-dry season periods, i.e., high wind in Cimenyan-Java (2021), flash flood in Luwu-Sulawesi (2021), storm surges in Java-Bali (2020), tropical cyclone in Flores-east Nusa Tenggara (2021). Our recent studies investigated the mechanisms of several extreme weather events mentioned previously. We suggested the role of moderate to extreme warming local seas in developing favorable conditions for extreme weather events. Due to the highly warming ocean under the global warming condition that tends to increase significantly in intensity and frequency, extreme weather events could reoccur with varying severity and become worse. Considering the preparation for climate change adaptation, we need more detailed monitoring data, correct analysis, and accurate short-range numerical weather prediction to anticipate and mitigate the risk of weather-related hydrometeorological disasters.
09:30–09:45 – Maxime Colin (ZMT), Vishal Dixit, Jan O. Haerter
Running regional models as if they were global? Atmospheric simulations over an aquapatch to understand the role of convection, land, and ocean in the “hysteresis” of the tropical rain band migration
The tropical rain band is the most prominent feature of convective precipitation on Earth. It
includes the monsoons over land, and the ITCZ over the ocean. The dominant theories are based on large-scale energetics and on a circulation regime shift, but they do not take into account the life cycle of convection. To estimate the role of convection on the tropical rain band migration, we run idealised simulations of the seasonal cycle over an aquapatch, with just an atmosphere. We show that (1) there are several monsoon non-linearities, including the rapid and delayed monsoon onset, (2) there is a hysteresis in the seasonal migration of the tropical rain band, even when no oceanic processes are taken into account, demonstrating the importance of atmospheric memory. By comparing simulations over ocean and over a pseudo-land, we also suggest that the monsoon retreat behaves differently, but the monsoon onset properties are fairly robust.
09:45–10:00 – Ming Li (University of Maryland, USA)
Impacts of Tropical Cyclones on Harmful Algal Blooms in Coastal Oceans
Tropical cyclones have been linked to harmful algal blooms (HABs) in coastal oceans, but the underlying mechanisms are not well understood. Moreover, the plankton response varied, with large blooms developing after some storms but minimal or negative growth during other storms. To understand how tropical storms affect HABs, we need to couple atmospheric, hydrodynamic, biogeochemical and HAB models. We developed such an integrated modeling system to investigate a large Karenia brevis bloom that developed on the West Florida Shelf after the passage of Hurricane Ian in 2022. We showed that Hurricane Ian drove the bloom in two ways: (1) the northerly winds generated onshore bottom currents and transported subsurface K. brevis cells toward the coast; (2) the large pulse of riverine nutrient loading fueled the growth of K. brevis cells for several months. This mechanistic approach also enabled us to discern the individual effects of different components of storm forcing.
10:00–10:15 – Ronny Peters (TU Dresden, Germany)
Is there a way from the process scale to the ecosystem model?
Coastal ecosystems are defined by their ability to thrive in saltwater environments. Plant water uptake, excluding salt in the root zone, is a process of permanent salinisation of the soil. Tide-induced dilution processes counteract this process. Therefore, they are a decisive factor in the plants’ growing conditions. The efficiency of these processes depends on local soil conditions, such as hydraulic conductivity and the presence of macropores – in mangroves, these are primarily crab burrows. Understanding and modelling these processes, as well as exploring the conditions, which can vary significantly over short distances, requires a focus on scales ranging from a few square metres to plot size. Simultaneously, the physical description of water fluxes and diffusion processes relies on a small temporal scale of minutes. This conflicts with the requirements of forest modelling, which deals with scales of hectares and tree lifetimes. The presentation will focus on how to solve this problem.
☕ 10:15–11:00 – Morning Coffee Break
11:00–11:30 – Keynote: Julia Moriarty (University of Colorado, USA)
Using high-resolution hydrodynamic-sediment–biogeochemistry models to understand data-sparse coastal systems
Coastal systems are impacted by an array of hydrodynamic, sediment transport and biogeochemical processes that operate on temporal and spatial scales ranging from sub-millimeter to kilometers, and from hours to decades or longer. This talk will focus on lessons learned from using high-resolution models to better understand and quantify coupled sediment transport – biogeochemical processes such as organic matter transport and fate in data-rich temperate systems, and how high- and low-resolution models may be applied to data poor systems such as the Arctic or tropics. In particular, recent research with high-resolution models has underscored the importance of accounting for resuspension and other sediment transport processes when modeling biogeochemical processes such as organic matter transport and fate. Ongoing work suggests that lower-resolution models, which are more easily applied to data-poor systems, may capture certain aspects of these dynamics in a robust way.
11:30–11:45 – Yuley M. Cardona Orozco (CEMarin, Colombia)
Salinity and Mixing Dynamics in the Magdalena River Estuary and Plume: Insights from a High-Resolution Delft3D Model ensemble
Estuaries reflect the intricate interplay between land and ocean processes, where temporal and spatial scales of processes add to the complexity of understanding these systems. Here, we present the hydrodynamic and salinity structure of the estuary and plume of a large, tropical, strongly stratified, and human-intervened river, the Magdalena, through a high-resolution Delft3D model ensemble and in situ data. The model simulations (21 runs) capture seasonal and diurnal variability under low, mid, and high discharge scenarios. Results show that stratification and mixing are strongly discharge-dependent: low flows promote saline intrusion and weak bottom-generated turbulence, while high flows drive a lift-off plume and intense pycnocline mixing. The transition to lift-off occurs near the 30th discharge percentile (~5200 m³/s). Hydraulic jumps in the plume mid-field contribute minor additional mixing. Salinity intrusion scales nonlinearly with discharge, and micro-tides enhance diurnal salinity variability. Findings highlight the model’s ability to resolve fine-scale mixing and plume behavior, offering insight into land-sea exchange dynamics in human-impacted tropical estuaries.
11:45–12:00 – Florian Schütte (GEOMAR, Germany)
Linking physical processes to biological responses: Interdisciplinary observational insights into the enhanced biological productivity of the Cape Verde Archipelago
The Cape Verde Archipelago (CVA) exemplifies how topographic forcing (in the atmosphere and ocean) connects to local ecological outcomes in tropical coastal systems. Drawing on two decades of interdisciplinary observations, we identify three dominant mechanisms shaping ecosystem structure. First, wind–island interactions generate atmospheric wakes and productive eddy fields downstream of steep topography. Second, mesoscale eddies originating off West Africa deliver nitrate-rich waters that, when interacting with island bathymetry and local wind curl, amplify submesoscale mixing and internal wave activity. Third, tidal flows and internal wave breaking at specific hotspots cause vertical mixing up to 1000 times stronger than in open-ocean reference sites. Collectively, these processes enhance upward nitrate flux and chlorophyll concentrations, supporting diverse pelagic food webs. Importantly, the different forcings drive distinct ecological assemblages, underpinning the exceptional biodiversity of the CVA. The CVA thus demonstrates how cross-scale physical–ecological interactions translate physical forcing into regionally transferable ecosystem outcomes.
🍽 12:00–13:00 – Lunch Break (lunch provided on site)
Session 2: Human Dimensions in Tropical Coastal Processes
This session interprets the physical–ecological cascade in socio-economic terms, assessing how tropical countries and their coastal ecosystems may be impacted by climate change and other environmental pressures and what this implies for macroeconomic indicators, sectoral impacts, and socio-political stability. It reviews how macro- and meso-scale models can anticipate these changes, alongside strategies to mitigate greenhouse gases and adapt to evolving risks where an ocean–climate nexus is central. Guiding question: Which socio-economic indicators and case studies are most useful for linking coastal and ocean dynamics with economic impacts and resilience planning?
Chair: Michael Obersteiner (University of Oxford, UK)
13:00–13:30 – Keynote: Rob Dellink (OECD, France)
Socioeconomic trends, drivers of environmental pressures and projecting economy-environment interactions
Environmental changes are driven by a wide range of drivers, including socio-economic trends, such as demographic changes and income growth, and sectoral drivers including structural change and technological developments. The regional and sectoral composition of economic activity shifts over time, thereby influencing environmental pressures. This presentation will provide an overview of some of the expected trends for the coming decades, including the recently updated Shared Socioeconomic Pathways and detailed projections of economic activity and environmental pressure using the OECD in-house modelling, highlighting the crucial differences in circumstances for different regions. The presentation will also cover how biophysical impacts of environmental change in turn can affect the economy, and the critical role of adaptation in limiting impacts. Specific attention will be given to how such projections can inform scientific analysis, including for tropical coastal ecosystems management.
13:30–13:45 – Fredrick Kayusi (Pwani University, Kenya)
Harnessing climate information systems and artificial intelligence (AI) innovations in enhancing resilience to climate change in Africa
The ocean-climate relationship determines a unique tropical architecture, which produces increased seasonal and temporal variation of wind, waves, currents and thermal stratification. The objective is to identify how Climate Information Systems (CIS) and emerging artificial intelligence (AI) technologies can benefit Africa’s climate change resilience, with a focus on Kenya’s exposed coastal economies. The study employed a mixed-methods approach on the selected population; stratified random sampling was used to select 225 individuals who were administered structured questionnaires, interviews and Focused Group Discussion. Quantitative and qualitative methods were both used to study data such as Statistical packages and regression analysis. The results were that CIS has a high level of awareness of 40.9% “Very Aware,” and 41.8% of the respondents use AI occasionally. Regression analysis reveals a high positive relationship (R = 0.789) of CIS and AI with resilience explaining 61.9% of variance, highlighting indicators such as CIS awareness (coefficient = 0.441) and use of AI (coefficient = 0.358) as excellent predictors, whereas bottlenecks such as lack of infrastructure (36.0%) and awareness (28.4%) hinder effective implementation. The study recommends the mounting of gas analyzer sensors on smartphones to convert physical changes into electrical signals that can be interpreted by AI algorithm systems and automatically send collected data to various stations. The stakeholders should raise awareness and education on CIS and AI, invest in necessary infrastructure, and leverage partnership among the government, academia, and the private sector to mitigate challenges and develop resilience to climate change in Kenya’s coastal economies.
13:45–14:00 – Alvaro Calzadilla (UCL, UK)
The Economic Dynamics of Climate Change Impacts on Global Agriculture
Climate change is already reshaping global agricultural systems, with most regions experiencing declines in crop yields. However, the severity and nature of these impacts vary widely. This trend is expected to intensify, posing complex challenges for food security, trade, and economic stability. A global economic modelling approach is used to quantify the future economic impacts of climate change across sectors and across countries, considering local conditions in agricultural production and adjustment processes in both domestic and international markets. The analysis highlights the dynamic feedback between the direct impact of climate change on agricultural yields and the indirect effects of climate-induced changes in competitiveness and trade. It underscores the need for coordinated responses across disciplines to address the multifaceted consequences of climate change on agriculture and the global economy.
14:00–14:15 – Jun Rentschler (World Bank, Belgium)
From Villages to Megacities: Urban expansion patterns and escalating flood risks
Disaster losses are increasing and climate change is driving up the probability of extreme natural shocks. Yet it has also proved politically expedient to invoke climate change as an exogenous force that supposedly places disasters beyond the influence of local authorities. However, locally determined patterns of urbanization and spatial development are key factors to the exposure and vulnerability of people to climatic shocks. High-resolution spatial data show us that, since 1985, human settlements around the world—from villages to megacities—have expanded continuously and rapidly into present-day flood zones, especially in coastal areas. There is systematic evidence of a divergence in the exposure of countries to flood hazards. Instead of adapting their exposure, many countries continue to actively amplify their exposure to increasingly frequent climatic shocks. The implications are wide-ranging, affecting communities and economies — often stretching well beyond the flood zones.
14:15–14:30 – Bruno Meirelles de Oliveira (AZTI, Spain)
Resilience in Tropical Coastal Social-Ecological Systems: Patterns of Behavior Across Diverse Worldviews
The decline in global biodiversity and increasing risks from climate change disruptions, combined with the escalating demand from society for the ecosystem services provided by coastal social-ecological systems (SES), especially in tropical areas, instigate the research and governance communities’ interest in understanding and leveraging the resilience of these systems. Therefore, modelling the intertwined complexities of the environment and society, from where resilience emerges, is crucial. Our research presents a prototype of an integrated model that embraces coastal areas as SES in a coupled, complex, and intertwined approach. It builds on the ecosystem services coastal areas provide and integrates them with the resilience principles from the mainstream literature to reveal how resilience unfolds over time. Our results present the insights of this study with particular focus on the influence of society’s worldviews in the process. An additional study embodied these worldviews in the simulations, finally revealing resilience behavior differently depending on worldviews.
☕ 14:30–15:00 – Afternoon Coffee Break
15:00–15:15 – Alistair Smith (Cambridge Econometrics, UK)
Integrating economic and physical-ecological modelling: an E3ME case study
What are the economic costs of inaction on global emissions? What are the economic opportunities of investing in mitigation and resilience? The linkages between the economy and physical world are varied and complex. The identification of these linkages and incorporation in modelling scenarios allows us to explore these key questions. Economic models can provide insights to help motivate and inform decision making. A case study for Pakistan’s CCDR (Climate Country and Development Report) used E3ME, a global E3 (economy-energy-environment) model, to assess the macroeconomic impact of climate damages. Climate damages included flood damage to capital stock and infrastructure across climate scenarios. The results find real GDP losses up to 10% by 2050, with agriculture and manufacturing affected more deeply than services. This research helps to frame the case for action to minimise damages.
15:15–15:30 – Michael Obersteiner (University of Oxford, UK)
Managing Time-Lagged Climate Risks for Coastal Societies: Lasting Benefits of Temperature Peak-Shaving
Tropical coastal regions face escalating risks from time-lagged climate processes, particularly sea-level rise driven by ice-sheet loss and ocean heat uptake. These impacts unfold over centuries, exceed conventional planning horizons, and threaten the viability of small island states and low-lying coasts. Using a simplified Earth system emulator with impact dynamics, we show that temperature “peak-shaving” – temporary reduction of global warming via accelerated carbon removal or solar radiation management (SRM) – can lower the eventual stabilization level of sea-level rise. By moderating both the magnitude and duration of temperature overshoot, peak-shaving reduces long-term adaptation costs and the likelihood of crossing hard resilience limits. Our results highlight that socio-economic outcomes in vulnerable coastal regions depend not only on end-of-century temperature goals but also on the shape of mitigation pathways. This insight strengthens the case for incorporating overshoot risks and peak management into adaptation and macroeconomic resilience planning.
15:30–15:45 – Marie Fujitani (ZMT)
From Models to Meaning: Socio-Economic Indicators, Physical-Ecological Processes, and Coastal Resilience
“Modeling socio-economic dimensions across Tropical Coastal Ecosystems and the Earth System” (TropEcS) integrates decentralized socioeconomic processes with ecological and physical systems in earth systems modelling. The proposal emphasized its unique contribution to understanding the “feedbacks between social and ecological systems and the Earth system.” As a bridge to the panel discussion, this presentation reflects on the proposal and the process of selecting critical inputs, indicators, and feedbacks, following the guiding question for this panel: “What are the most useful socio-economic indicators for linking coastal and ocean dynamics with economic impacts and resilience planning?” This presentation will also highlight one of the central ambitions of TropEcS: to create a permanent, participatory knowledge hub for model and observation data, to be collected and analyzed collaboratively. This hub will facilitate essential dialogue between science and policy, necessary for effective and equitable resilience strategies. The ZMT sits at a unique crossroads of expertise and vision, with an unprecedented opportunity to become a world leader in knowledge integration to guide adaptation and planning for the world’s most vulnerable coasts.