How to use the Sea-Level Rise Projections User Story (#1)

“I need to see mean sea-level rise information now and in the future for different climate change scenarios so I can do a broad-scale preliminary evaluation of risks.”

1. What is a CoCliCo User Story?

User Stories are ready-made map datasets in the CoCliCo platform. They combine different types of important information to show scenarios for coastal risk resulting from sea-level rise, floods and / or erosion. These layers make complex analyses easier and help users to quickly get a sense of coastal risks.

User research showed that policymakers need clear, actionable data for flood directives, while urban planners want tools to assess local risks, and where infrastructure managers focus on long-term resilience planning. These insights helped shape User Stories to provide accessible, scenario-driven visualizations for diverse decision-making needs. There are six User Stories:

Sea Level Rise Projections
Inundation Distribution During a Flood Event
Building Exposure
Projections of Exposed People
Damage Costs of Exposed Infrastructures
Adaptation Based on Cost-Benefit Analysis

In this e-guideline, we walk you through the Sea Level Rise Projections User Story.

2. Introduction to Sea Level Rise Projections User Story

The CoCliCo Platform provides access to sea-level rise (SLR) projections based on the latest scientific assessments from the Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report (AR6), essential for understanding future changes and planning coastal adaptation.

Use the Sea Level Rise Projections User Story for detailed insights into how sea levels may change under different climate scenarios. With projections ranging from 0.3 to 1 meter by 2100—and continuing to rise—this data is crucial for assessing coastal flood risks, infrastructure planning, and long-term adaptation.

Unlike global estimates, these regional projections account for local factors like ocean circulation, ice melt, and land shifts, offering more precise insights for specific locations. This layer is a key foundation for flood models and supports all other User Stories in the platform.

3. Step-by-Step Platform Usage

Access the CoCliCo Platform:
1. On the left-hand menu bar, navigate to the “sea levels” category, then “Sea Level Rise Projections User Story” under “User Stories”.
Select a Scenario:
1. Choose a climate scenario (e.g., SSP1-2.6, SSP2-4.5, etc.), the percentile of the probabilistic projection (e.g. 17th, median or 83rd) and time horizon.
Analyze Visualizations:
1. Use interactive tools to zoom into regions and access localized insights.
2. Use the “Add to Dashboard” feature to retain charts and graphs for further comparison and analysis
3. Toggle on other layers, such as “natural hazards” and “exposure & vulnerability,” for more context on the impacts and risks faced by that area. For simpler comparisons, make sure you add your charts and graphs to your dashboard to compare across time and geographies and observe various layers and user stories of that area.
Further Analysis:
1. Export maps or raw datasets for further analysis in the Workbench or other GIS tools.
2. Assess local projections with vertical land motion (VLM) using our coastal hazard assessment.

4. Target Users & Intended Use

Target Users:

Policymakers implementing national and EU flood directives.
Urban planners and city authorities in coastal areas.
Infrastructure managers addressing coastal resilience.
Researchers and consultants assessing coastal risks.

Intended Use:
The layer provides simplified, robust visualizations for identifying coastal areas at risk from sea-level rise. It supports broad-scale assessments, preliminary decision-making, and compliance with policies like the European Flood Directive.

Key Benefits:

Enables informed risk assessments and adaptation planning at all scales (national to municipal).
Improves stakeholder engagement with clear, accessible data.
Aids investment prioritization and strategic land-use decisions.

5. Example of Use

“Using the Sea Level Rise projections User Stories, city planners identified their neighbourhoods as having a higher risk of permanent flooding related to sea level rise by 2050 under high-emission scenarios high-emission scenarios compared to other neighbourhoods in the country. This analysis informed their decisions to prioritize green infrastructure development in those areas, reducing potential damage costs by 30%.”

6. Data, Methods, and Model Overview

Data Sources:

CoCliCo’s regional sea-level projections are based on the IPCC AR6 dataset, incorporating all sea-level components except vertical land motions, which are corrected using GIA model outputs for improved regional accuracy.

IPCC AR6 (Fox-Kemper et al., 2021)
AR6 dataset is described and displayed at Sea Level Projection Tool – NASA Sea Level Change Portal and is publicly distributed at IPCC AR6 Sea Level Projections (Garner et al., 2022).
Glacial Isostatic Adjustment (GIA) model outputs (Caron et al., 2018)

Methods:

CoCliCo regional mean sea-level projections are constructed by combining the IPCC AR6 sea-level change dataset and the GIA model outputs of Caron et al. (2018), and propagating uncertainty following a Monte Carlo approach. The regional sea-level changes therefore include the changes in ocean density and circulation, the changes due to continental glaciers and ice-sheet mass loss and their respective regional spatial distribution, changes in landwater and groundwater, and the post-glacial rebound.

For three SSPs scenarios (i.e. SSP1-2.6, SSP2-4.5 and SSP5-8.5), the percentiles can be displayed, corresponding to the lower (17th), median (50th) and upper (83rd) bounds of the likely-range. One high-end scenario is also constructed from the 83rd percentile of the low-confidence SSP5-8.5 scenario of the IPCC AR6. High-end scenarios explore plausible – although unlikely – upper-tail sea-level scenarios beyond the likely range: i.e. when uncertainty tolerance is low and robust decision-making is preferable.

Model Outputs:

Visualizations display regional sea-level changes at decadal timesteps from 2030 to 2150 with respect to the reference period 1995-2014 for three SSPs scenarios and one high-end scenario.
Interactive features allow scenario comparisons and data downloads for local and regional decision-making.

Limitations:

Limitations are twofold: first, vertical ground motions unrelated to the glacial isostatic adjustment are not integrated. Yet CoCliCo’s research has shown that urban areas and populations located in coastal flood plains in Europe (excluding Fennoscandia) are affected by subsidence of approximately 1mm/year in average.

Second, sea level projections shown here have a resolution of 1°x1°, therefore not taking into account mesoscale ocean processes acting on the continental shelf and within semi-enclosed bassins such as the Mediterranean. Research undertaken by CoCliCo by ENEA and Mercator Ocean (D3.3, soon to be published) suggest that the order of magnitude of the error due to neglecting these processes can reach +/-10cm in Europe.

7. Further Analysis

Beside GIA, coastal regions in Europe can experience significant vertical land motion (VLM) which can be strong, robust and that can be assessed locally. There is for instance well known subsidence along the Italian Adriatic, the Netherlands or even in more localized shorelines such as the Aksiou delta next to Thessaloniki in Greece. This subsidence context can strongly inflate coastal hazards locally and should therefore be accounted for. The CoCliCo project explored local VLMs using the land vertical velocity estimates from the Copernicus European Ground Motion Service (EGMS) derived over the period 2016-2021 (Thiéblemont et al., 2024). While these estimates are not implemented in the regional sea-level projections of CoCliCo, they have been considered for the coastal hazard assessment and can be explored as an exploratory tool.