Methodology
Saferland evaluates climate resilience by combining seven independent risk factors into a single score, supplemented by a ten-domain Regional Climate Guide covering broader socioeconomic impacts through 2100. This page documents how each factor is measured, the scientific basis for our thresholds, data sources used, and known limitations. All scoring values reflect the production codebase. Key sources include IPCC AR6, DMI technical reports, Spildevandskomiteen (SVK) standards, GEUS geological surveys, and over 70 peer-reviewed studies spanning climate science, economics, geopolitics, and public health.
Sea Flood Risk
What we measure
The site's elevation above mean sea level determines vulnerability to storm surges, sea-level rise, and coastal flooding. Flood risk increases non-linearly as elevation approaches sea level because even modest storm surges can inundate large areas of flat, low-lying terrain — a defining characteristic of Danish geography.
Scientific basis
Denmark's highest natural point (Mollehøj) is just 170.86m. Roughly 18% of Denmark's land area lies below 5m elevation (DVR90). The country experienced its worst recorded storm surge on 13 November 1872, when water levels reached 3.0–3.3m above mean sea level along the inner Danish waters (southern Zealand, Lolland-Falster), destroying over 2,000 buildings and killing 80 people.
DMI Technical Report 15-01 (Ditlevsen et al., 2018); Kystdirektoratet storm surge recordsDVR90 datum caveat
Danish elevation data uses DVR90 (Dansk Vertikal Reference 1990), which was calibrated to mean sea level circa 1990. Due to sea-level rise since then, DVR90 zero is now approximately 5–10cm below actual present-day mean sea level. This means an elevation of “1.0m DVR90” is effectively closer to 0.9–0.95m above today's water. Our scoring does not add this offset but users should be aware that stated elevations have a small built-in optimism.
Geodatastyrelsen: DVR90 definition; DMI sea level observations Copenhagen 1890–2023Regional land movement
Post-glacial isostatic adjustment causes northern Jutland/Scandinavia to rise (+1–2 mm/yr at Skagen) while southern Denmark sinks (−0.5 to −1.0 mm/yr on Lolland-Falster and southern Zealand). Over a century, this adds up to 5–10cm of effective additional sea-level rise for southern Denmark on top of global projections.
Vestol et al. (2019): NKG2016LU land uplift model; Khan et al. (2019)Data sources
| Source | Provides | Resolution / Accuracy |
|---|---|---|
| Open-Meteo Elevation API | Point elevation (Copernicus DEM / SRTM blend) | ~30m horizontal, ±1–2m vertical accuracy |
| AWS Terrarium Tiles | RGB-encoded elevation for heatmap & flood layer | ~30m per pixel at zoom 12; derived from SRTM/ASTER |
| Dataforsyningen DHM (when token available) | LiDAR-derived flood zone confirmation | 0.4m ground resolution (Denmark's national DEM) |
How we calculate
The climateScore() function applies a stepped adjustment based on site elevation.
Starting from the baseline score of 72:
| Elevation | Adjustment | Rationale |
|---|---|---|
| ≥ 40 m | +12 | Above all projected surge + SLR scenarios through 2150 |
| ≥ 25 m | +7 | Safe from all IPCC AR6 scenarios including SSP5-8.5 |
| ≥ 15 m | +2 | Above 100-year North Sea surge (~4–5m DVR90) + worst-case SLR |
| ≥ 10 m | −5 | Within range of compound events (surge + SLR + rainfall) |
| ≥ 6 m | −12 | Within North Sea 100-year surge range (4–5m + SLR) |
| ≥ 3 m | −22 | Below 1872-type inner water surge (~3.3m DVR90) |
| < 3 m | −35 | Severe risk; most scenarios inundate by 2100 |
Storm surge context
100-year return-period surge heights vary dramatically across Denmark:
| Coast | 100-yr surge (DVR90) | Source |
|---|---|---|
| North Sea (Esbjerg, Ribe) | 4.0–5.0 m | DMI Technical Report 15-01 |
| Inner Danish waters (Copenhagen) | 1.5–2.0 m | DMI / Kystdirektoratet |
| Southern Zealand / Lolland (1872 type) | 2.5–3.3 m | Historical record + DMI modelling |
| Limfjorden | 2.0–2.5 m | Kystdirektoratet |
The elevation also feeds into the Terrarium-based Flood Risk Layer, which classifies every pixel
against the user-adjustable floodThresholdM slider (default 1.0m):
≤ 0.5 m transparent (already water)
≤ thresh × 0.5 dark blue, 210 alpha — deep inundation
≤ thresh blue, 175 alpha — inundation zone
≤ thresh × 1.5 light blue, 100 alpha — at-risk fringe
≤ thresh × 2.5 faint blue, 45 alpha
else transparent
Limitations
- Open-Meteo DEM (~30m) cannot resolve dykes, levees, raised roads, or micro-topography. Danish DHM (0.4m) is far more precise but only used for flood zone confirmation, not point elevation.
- DVR90 zero is ~5–10cm below current MSL — stated elevations are slightly optimistic.
- Southern Denmark's land subsidence (−0.5 to −1.0 mm/yr) is not added to score adjustments.
- No distinction between protected (dyked) and unprotected coastline.
- Tidal range and local surge dynamics are not modelled — we use national-scale surge statistics.
Rain & Runoff Risk
What we measure
The likelihood of stormwater accumulating at a location during an extreme cloudburst event. This combines soil permeability, surface type, topographic position, and proximity to waterways that may overflow. Denmark is particularly exposed to cloudbursts: the 2 July 2011 Copenhagen event delivered 135mm in 2 hours, causing DKK 6.2 billion in damage.
Forsikring & Pension (2012): Copenhagen cloudburst damage estimate; DMI Climate AtlasScientific basis
Danish sewer design standards (SVK Skrift 27)
Danish municipal sewers are designed to the standards set by Spildevandskomiteen (The Danish Water Pollution Committee, SVK). SVK Skrift 27 (latest edition 2014) specifies that combined sewer systems must handle a T=5 to T=10 year return period event without surface flooding. For separate stormwater systems, T=5 years is typical.
Spildevandskomiteen: Skrift 27 — Funktionspraksis for afloebssystemer under regn (2014)A T=5–10 year event in Copenhagen corresponds to approximately 15–25 mm/hr rainfall intensity (depending on duration and location). A 100-year cloudburst produces approximately 50–60 mm/hr raw, which rises to 60–78 mm/hr when applying the SVK-recommended climate factor of 1.2–1.3 for future conditions.
SVK Skrift 29 (2006): Forventede aendringer i ekstremregn; DMI IDF curves for CopenhagenRunoff coefficients (φ-coefficients)
We use the SVK/Spildevandskomiteen rational method φ-coefficients for Danish urban surfaces, which determine what fraction of rainfall becomes surface runoff:
| Surface type | φ coefficient | SVK category |
|---|---|---|
| Asphalt / concrete (roads, commercial) | 0.80 – 0.90 | Tæt bymæssig bebyggelse |
| Industrial areas | 0.60 – 0.80 | Industri, delvist befæstet |
| Residential composite (villa quarter) | 0.30 – 0.60 | Villakvarter, blandet |
| Parks / lawns | 0.05 – 0.15 | Parkarealer, græs |
| Clay farmland | 0.15 – 0.30 | Dyrkede marker på moræneler |
| Sandy farmland / heathland | 0.05 – 0.15 | Sandede arealer |
Climate change trend
DMI projections indicate a 15–25% increase in extreme rainfall intensity by 2100 under RCP4.5/SSP2-4.5. SVK Skrift 29 recommends applying a climate factor of 1.2 (moderate) to 1.3 (precautionary) to current IDF curves for infrastructure planning. Our scoring uses current intensities but notes the trend in the risk assessment.
SVK Skrift 29 (2006); DMI Technical Report 15-07; Olesen et al. (2014): Fremtidige klimaendringer i DanmarkData sources
| Source | Provides | Resolution / Accuracy |
|---|---|---|
| GEUS WMS (Jordartskort 1:200,000) | Soil type classification (clay, sand, peat, etc.) | 1:200,000 geological survey; boundary accuracy ±100–250m |
| OpenStreetMap Overpass API | Land-use polygons (urban surface type) | Crowdsourced, variable completeness |
| Open-Meteo Elevation API | 5×5 grid for topographic depression analysis | ~30m DEM (vastly coarser than DHM's 0.4m) |
How we calculate
The riskRain() function evaluates a composite of sub-factors. Starting baseline: 25
(Denmark's flat terrain and high rainfall intensity mean every property has meaningful cloudburst risk).
| Condition | Points added | Rationale |
|---|---|---|
| Elevation < 5m | +35 | Low-lying ground with nowhere to drain |
| Elevation 5–12m | +15 | Limited gravity drainage |
| Clay soil (no urban override) | +20 | SVK φ ≈ 0.15–0.30 on clay farmland |
| Urban managed drainage | −5 | Active sewer infrastructure removes water |
| Depression score ≥ 65 | +18 | DMI: depressions accumulate 3–5× local rainfall |
| Floodplain confirmed (DHM) | +15 | LiDAR confirms flood zone |
| Ridge position (score ≤ 20) | −8 | Water drains away by gravity |
Urban surface types use SVK φ-coefficients converted to our scale:
| Land Use | Runoff % | Risk Delta | SVK basis |
|---|---|---|---|
| Commercial / city centre | 85% | +5 | φ = 0.80–0.90, managed sewer |
| Industrial zone | 75% | +18 | φ = 0.60–0.80, partial drainage |
| Construction site | 70% | +25 | Compacted soil, no drainage |
| Residential area | 45% | +3 | φ = 0.30–0.60, composite |
| Farmland | 25% | 0 | φ = 0.15–0.30 on clay |
| Allotments | 18% | −10 | Near-natural infiltration |
| Cemetery / green space | 15% | −8 | Permeable ground cover |
| Park | 12% | −14 | φ = 0.05–0.15 |
| Forest | 8% | −14 | φ < 0.10, high interception |
Limitations
- No real-time rainfall data — uses statistical cloudburst thresholds, not forecasts.
- Municipal sewer capacity varies by neighbourhood; SVK T=5–10yr standard is a national average.
- Surface permeability is approximated from broad OSM land-use categories, not field measurements.
- Green roofs, retention basins, LAR/SUDS features, and recent climate adaptation projects are not detected.
- The 30m DEM cannot resolve urban micro-topography (sunken roads, underpasses, courtyards) that traps water.
Topographic Position
What we measure
Whether a location sits in a topographic low point (basin or depression) where rainwater and floodwater naturally collect, or on a ridge or slope where water drains away. In Denmark's flat terrain, even subtle depressions of 0.5–1.0m can trap significant volumes of stormwater.
Scientific basis
The DMI Cloudburst Atlas (Skørregnskort) for Danish municipalities demonstrates that topographic depressions accumulate 3–5× local precipitation depth during cloudbursts, as water flows downhill and pools in the lowest points. The Topographic Position Index (TPI), widely used in geomorphological analysis, classifies landforms by comparing a point's elevation to its neighbourhood mean — exactly the approach we implement.
Weiss (2001): Topographic Position and Landforms Analysis (ESRI); DMI Skørregnskort methodology; Jenness (2006): TPI extension for ArcGISData sources
| Source | Provides | Resolution / Accuracy |
|---|---|---|
| Open-Meteo Elevation API (batch) | 25-point grid elevations in a single request | ~30m DEM, 25 sample points over ±1km |
How we calculate
The analyseTopographicContext() function builds a 5×5 grid centred on the target location,
spanning ±1km (0.009° latitude, 0.012° longitude). All 25 elevations are fetched in a
single batched API call.
higherFrac = (points higher than centre ± 0.3m) / 24
depressionScore = round(higherFrac × 100) // 0–100
The ±0.3m tolerance prevents noise in flat terrain from creating false depression signals. The depression score maps to a position label and a score adjustment:
| Depression Score | Position | Adjustment | Hydrological meaning |
|---|---|---|---|
| ≥ 85 | Basin | −24 | Collects ALL surrounding runoff; 3–5× rainfall accumulation |
| ≥ 65 | Depression | −16 | Strong convergence zone; water pools during cloudburst |
| ≥ 45 | Slight hollow | −6 | Some convergence; partial pooling likely |
| 35 – 44 | Flat terrain | 0 | Neutral — sheet flow, no preferential accumulation |
| 21 – 34 | Slope | +3 | Water moves downhill; limited residence time |
| ≤ 20 | Ridge / elevated | +7 | Water drains away in all directions |
Additional outputs include deltaFromMean (centre vs. surrounding average),
relief (max−min elevation across the grid), and runoffRisk
(qualitative label based on all topographic indicators).
Limitations
- The 5×5 grid at ~500m spacing misses narrow depressions smaller than one grid cell (<500m wide).
- Urban terrain features (underpasses, sunken car parks, enclosed courtyards) are below the 30m DEM resolution.
- The ±0.3m tolerance may miss very subtle depressions in western Jutland heathland (relief <1m over several km).
- No flow direction or accumulation modelling — only static position classification. A true D8/D-inf flow accumulation analysis would require the 0.4m DHM.
River / Waterway Risk
What we measure
The combined flood risk from nearby rivers, streams, canals, and other waterbodies. We consider both horizontal proximity and vertical elevation difference — features that are close to the site and at or above its elevation pose the greatest threat.
Scientific basis
Proximity–risk relationship
Danish insurance data (Forsikring & Pension) shows that properties within 100m of a watercourse have significantly elevated claims rates for water damage. The risk decays with distance following an approximate power-law relationship. Our model uses a proximity exponent of 1.5:
proximityFactor = 1 - (distance / 400) // normalised 0–1 over 400m search radius
contribution = baseWeight × proximityFactor^1.5 × elevRiskMultiplier
The 1.5 exponent produces a steeper-than-linear decay: risk drops rapidly beyond ~150m but remains non-zero out to 400m. Empirical studies of riverine flood damage show exponents between 1.0 and 2.0, with 1.5 as a reasonable midpoint for Danish lowland watercourses.
Forsikring & Pension: Skadedata for oversvommelse (2018); Merz et al. (2010): Assessment of economic flood damage, Natural HazardsDHM vandloeb oversvoemmelse model
When a Dataforsyningen token is available, Saferland probes the DHM vandloeb_overloeb
WMS layer. This is a static bathtub/fill model derived from 0.4m LiDAR data —
it identifies areas that would be inundated if watercourse levels rose by a given threshold (1m, 3m, etc.).
It does not incorporate hydrodynamic flow, channel capacity, or bridge constrictions.
Data sources
| Source | Provides | Resolution / Accuracy |
|---|---|---|
| OpenStreetMap Overpass API | Waterways and water bodies within 400m bbox | Crowdsourced geometry; good for major features, variable for minor ditches |
| Open-Meteo Elevation API | Elevation at each water feature (top 8 closest) | ~30m DEM — approximates water surface, not actual gauge level |
| Dataforsyningen DHM vandloeb_overloeb | LiDAR-derived static flood zone (bathtub model) | 0.4m LiDAR; authoritative for terrain but simplified hydrology |
How we calculate
The analyseWaterFeatures() function runs three passes:
Pass 1 — Classify
Each OSM element is assigned a baseWeight reflecting its flood potential.
Tidal and decorative features are discounted or skipped. Urban drains and ditches have their weight halved
(managed infrastructure reduces risk).
| Waterway Type | Base Weight | Rationale |
|---|---|---|
| River | 10 | Largest flood potential; carries upstream catchment |
| Stream | 6 | Moderate flood potential; common in Danish lowlands |
| Canal | 4 | Managed but can overflow; harbour canals = surge risk |
| Drain | 2 | Engineered; low but non-zero overflow risk |
| Ditch | 1 | Minor; relevant mainly for waterlogging |
Pass 2 — Elevation sample
The 8 closest features are sampled for elevation via Open-Meteo (5s timeout per feature, parallel). This determines the vertical relationship between the site and each water feature.
Pass 3 — Risk scoring
The elevRiskMultiplier adjusts based on the site's elevation relative to the water feature:
| Condition | Multiplier | Rationale |
|---|---|---|
| Site below water surface | 2.5× | Gravity drains water toward site; most dangerous |
| Within flood surge range | 0.8 – 2.0× | Overflow could reach site during high flow |
| Well above water surface | 0.05× | Terrain provides natural protection |
Contributions are accumulated and normalised:
maxPossibleRisk = 52.16 // river@10m × 2.5 + stream@close × 2.0 + ...
waterRiskScore = min(100, accumulated / maxPossibleRisk × 100)
The waterway score maps to climate score adjustments:
| Water Risk Score | Adjustment | Meaning |
|---|---|---|
| ≥ 70 | −28 | Close to major waterway, below flood level |
| ≥ 45 | −15 | Significant waterway exposure |
| ≥ 25 | −8 | Moderate proximity risk |
| ≥ 10 | −4 | Minor waterway presence |
| < 10 | 0 | No significant waterway risk |
When DHM confirms an active flood zone, a floodplainRisk flag adds −12 additional points.
When DHM shows the site is outside the flood zone despite OSM waterways being nearby,
the risk score is reduced by 10 points (terrain-protected).
Limitations
- OSM waterway coverage varies; minor streams and culverted watercourses may be missing.
- Elevation sampling uses ~30m DEM, not actual water surface gauge data — overestimates depth for incised channels.
- DHM vandloeb is a static bathtub model, not hydrodynamic — it does not account for channel capacity, bridge constrictions, or flood defences.
- Culverted or piped watercourses (common in Danish cities) are invisible in OSM data.
- No precipitation-runoff modelling — risk is proximity-based, not simulation-based.
Soil Drainage
What we measure
The underlying soil type, which determines how quickly rainwater infiltrates into the ground versus pooling on the surface. Clay-rich soils (moræneler) and peat soils have very low permeability and significantly increase surface water risk.
Scientific basis
Danish till (moræneler) hydraulic conductivity
Danish moræneler (glacial till clay) has a matrix hydraulic conductivity of approximately 10−9 m/s — essentially impermeable. However, field-scale measurements by Fredericia (1990) demonstrated that fractured Danish till has bulk hydraulic conductivity 100–1,000× higher than the matrix value, due to desiccation cracks and fracture networks in the upper 2–4m. This means water can penetrate more quickly than pure clay would suggest, but the fractures saturate rapidly and the soil reverts to near-impermeable behaviour during sustained rainfall.
Fredericia, J. (1990): Saturated hydraulic conductivity of clayey tills and the role of fractures. Nordic Hydrology, 21(2), 119–132For surface runoff purposes, the effective runoff coefficient on moræneler is φ ≈ 0.15–0.30 (SVK), meaning 15–30% of rainfall runs off during short events. During sustained cloudburst events (>30 min), the effective runoff increases significantly as fractures fill and surface saturation occurs.
Peat soil subsidence
Peat soils (tørvejord) pose a dual risk: extremely low permeability and ongoing subsidence. Drained peat in agricultural use subsides at approximately 1–2 cm/year due to oxidative decomposition. Over decades, this progressively lowers the land surface, increasing flood vulnerability. Areas like Lammefjorden (western Zealand) and Store Vildmose (northern Jutland) have subsided by 1–3m since drainage.
Greve et al. (2014): Estimating peat soil loss in Denmark; GEUS geological survey dataGroundwater considerations
In low-lying clay areas (especially Copenhagen), groundwater levels have been rising since the 1990s as
industrial water extraction decreased. High groundwater reduces the soil's capacity to absorb rainfall
and increases basement flooding risk. We approximate groundwater risk from elevation and waterway proximity
(the riskGroundwater() function), but cannot directly measure groundwater table depth.
Data sources
| Source | Provides | Resolution / Accuracy |
|---|---|---|
| GEUS WMS Jordartskort 1:200,000 | Soil type classification via GetFeatureInfo | 1:200,000; boundary accuracy ±100–250m |
| OpenStreetMap Overpass API | Urban land-use polygon for surface override | Crowdsourced, variable |
How we calculate
The isInClayZone() function sends a WMS GetFeatureInfo request to the GEUS server
at an 800×640 virtual map centred on the target point. It parses the Jordart attribute from
the GML response and classifies it into one of four risk levels:
| Risk Level | Soil Types (Danish geological terms) | Adjustment | Ksat range |
|---|---|---|---|
| Peat | tørv, ferskvandstørv, ferskvandsdannelser, kær og mose | −15 | 10−8–10−6 m/s + subsidence |
| High (clay) | moræneler, issøler, marint ler, ferskvandler, søler | −15 | Matrix: ~10−9 m/s; bulk: 10−7–10−6 |
| Moderate | morænegrus, moræne, extramarginale aflejringer, issøsand, postglacialt hav | −6 | 10−6–10−4 m/s |
| Low (sandy) | smeltevandssand, flyvesand, klitsand, strandvoldsaflejringer, hedeslette | 0 | 10−5–10−3 m/s |
When a site falls within an OSM-mapped urban land-use polygon, the binary soil classification is
supplemented by the urban surface type's runoff coefficient. The classifyUrbanSurface()
function applies the surface risk delta (scaled by 0.6) to the soil component of the climate score.
Limitations
- GEUS 1:200,000 boundaries can be off by 100–250m — a property near a boundary may be misclassified.
- GEUS coverage is Denmark only; locations outside Denmark receive no soil data.
- Artificial fill, compacted ground, and post-construction surfaces are not reflected.
- Groundwater table depth is estimated indirectly from elevation and hydrology, not measured.
- Fredericia (1990) fracture conductivity means moræneler is not as impermeable as the matrix K suggests, but during sustained rainfall the effective permeability drops back toward the matrix value.
- Peat subsidence (1–2 cm/yr) is not dynamically modelled — current elevation is used as-is.
Coast Distance
What we measure
The shortest distance from the site to the nearest coastline, measured perpendicular to actual coastline geometry (not point-to-point). Proximity to the coast increases exposure to storm surges, salt spray, and long-term erosion.
Scientific basis
Coastal erosion rates
Kystdirektoratet (the Danish Coastal Authority) monitors erosion along the entire Danish coastline. Erosion rates vary dramatically:
| Coast type | Typical retreat rate | Location examples |
|---|---|---|
| West Jutland sandy coast | 0.5 – 2.0 m/yr | Blåvand, Thorsminde, Agger |
| Moraine clay cliffs | 0.1 – 0.5 m/yr | Stevns Klint, Møns Klint, Fur |
| Inner waters (sheltered) | < 0.1 m/yr | Fyn archipelago, Øresund |
| Nourished beaches | Net stable (managed) | Skagen, North Sea coast (post-nourishment) |
Cliff erosion mechanism
Clay cliffs in Denmark (e.g. Stevns Klint) erode through rotational slides and mudflows when the toe is undercut by wave action and the clay becomes saturated. The retreat is episodic rather than gradual: a single storm can remove several metres of cliff. Our model detects cliff situations (elevation ≥ 8m within 500m of coast) and applies an erosion penalty instead of a sea-flood penalty.
DMI Denmark-specific sea-level rise
IPCC AR6 provides global mean SLR projections, but Denmark experiences approximately 10–15% higher relative sea-level rise than the global mean along the North Sea coast, due to gravitational fingerprinting (proximity to melting Greenland ice redistributes melt water), ocean dynamics, and regional land subsidence in southern Denmark.
DMI Technical Report 21-XX: Regional sea level projections for Denmark; Bamber et al. (2019): Ice sheet contributions to future sea-level rise, PNASData sources
| Source | Provides | Resolution / Accuracy |
|---|---|---|
| OpenStreetMap Overpass API | natural=coastline ways within stepped radii (5km → 25km → 60km) | Crowdsourced polylines, typically 10–50m vertex spacing |
| Hardcoded Øresund/Kattegat polyline | Fallback coast geometry if Overpass is unreachable | Approximate, ~500m accuracy |
How we calculate
The fetchCoastDist() function uses a stepped-radius search strategy to minimise Overpass
query load:
Step 1: 5 km radius → if coastline found, compute exact distance
Step 2: 25 km radius → expand search if step 1 found nothing
Step 3: 60 km radius → final expansion
An LRU cache (8 entries, 300m hit radius) prevents redundant queries for nearby points.
Distance is computed via distToPolyline(), which finds the minimum perpendicular distance
to each segment of every coastline way using the distToSegment() function.
Score adjustments from climateScore():
| Coast Distance | Adjustment | Condition |
|---|---|---|
| ≥ 20 km | +8 | All elevations — genuinely inland |
| ≥ 10 km | +3 | All elevations |
| ≥ 5 km | −5 | Low elevation: within surge propagation zone |
| ≥ 2 km | −14 | Low elevation: high surge exposure |
| < 2 km | −25 | Low elevation: direct coastal flood risk |
Cliff erosion path
When elevation ≥ 8m and distance < 0.5km, the site is flagged as a potential cliff location. Instead of flooding risk, it receives a −16 point cliff erosion penalty. For elevation ≥ 6m within 1.5km, a milder −8 penalty applies for possible cliff proximity.
Limitations
- OSM coastline data may lag behind actual shoreline changes from erosion or land reclamation by months to years.
- The stepped search can miss very narrow inlets or fjords if they fall between radius thresholds.
- No distinction between protected (dyked, nourished) and unprotected coastline.
- Cliff erosion rate is not modelled — only the cliff position is detected; actual retreat rates (0.1–2.0 m/yr) are not factored into the score.
- Denmark-specific SLR (+10–15% above IPCC global) is documented but not yet added as an explicit correction to the elevation scoring.
Overall Climate Score
What we measure
A single composite score from 5 to 95 that summarises the climate resilience of a location by combining all individual risk factors. Higher scores indicate greater resilience. The score is calibrated for Danish geography but applies to all supported countries.
How we calculate
The climateScore() function starts from a baseline of 72. Denmark’s
low-lying geography, high rainfall intensity, and extensive coastline mean that non-trivial climate risk
exists virtually everywhere, so the baseline is already well below the top of the scale.
Each factor applies its adjustment (detailed in the sections above), and the final sum is clamped to the range 5–95:
score = 72
score += elevationAdjustment // -35 to +12
score += coastAdjustment // -25 to +8
score += cliffPenalty // -16 or 0
score += soilAdjustment // -15 to 0
score += urbanSurfaceDelta × 0.6 // scaled riskDelta
score += waterwayAdjustment // -28 to +4
score += floodplainPenalty // -12 or 0
score += topographyAdjustment // -24 to +7
score = clamp(score, 5, 95)
Score bands
| Range | Label | Indicator |
|---|---|---|
| 75 – 95 | Good | Green |
| 62 – 74 | Acceptable | Green (60% opacity) |
| 48 – 61 | Moderate risk | Amber |
| 35 – 47 | Elevated risk | Amber (60% opacity) |
| 20 – 34 | High risk | Red (70% opacity) |
| 5 – 19 | Very high risk | Red |
Climate scenario projections
Saferland models five sea-level rise scenarios based on IPCC AR6 WG1 Chapter 9 and supplementary Danish research:
| Scenario | SSP Pathway | SLR by 2050 | SLR by 2100 | Source notes |
|---|---|---|---|---|
| Paris 1.5°C | SSP1-1.9 | 0.15 m | 0.35 m | IPCC AR6 median: 0.28–0.55m global; DK +10–15% |
| Current policies | SSP1-2.6 | 0.20 m | 0.50 m | NDC trajectory; DK adaptation planning lower-middle |
| Slow transition | SSP2-4.5 | 0.25 m | 0.75 m | Default scenario; Copenhagen-specific: ~0.68–0.82m |
| Fossil fuel path | SSP5-8.5 | 0.28 m | 1.10 m | IPCC likely: 0.63–1.01m; low-confidence upper: 1.6m |
| WAIS collapse | Beyond SSP5-8.5 | 0.40 m | 2.50 m | AR6 “cannot be ruled out”; ~5% tail probability |
The SLR projections feed into buildClimateConsiderations(), which presents decade-by-decade
risk across ten domains (see Regional Climate Guide below). Storm surge is added
on top of SLR: 2.0m for sites <3km from coast, 1.5m for 3–8km, 1.0m beyond.
These surge values approximate the range between inner Danish waters (~1.5m) and North Sea coast (~4–5m),
weighted conservatively.
Limitations
- The score is an index, not a probability — it cannot predict whether a specific event will occur at a specific time.
- Factor weights are expert-calibrated using Danish climate data, not derived from statistical loss modelling or machine learning.
- Interactions between factors (clay + depression + waterway) are partially captured through additive scoring but not through a full multivariate simulation.
- The 5–95 clamping means extreme combinations cannot produce a score of 0 or 100.
- Engineered defences (dykes, pumps, retention basins, flood gates) are not accounted for.
- Denmark-specific SLR (+10–15% above IPCC global) is noted in scenario descriptions but not applied as an explicit multiplier to score adjustments.
- The score reflects present-day and projected conditions but does not model planned or ongoing adaptation measures.
Regional Climate Guide
Saferland’s Regional Climate Guide goes beyond the physical risk score to present a broader picture
of how climate change may affect a Danish property and its surroundings across ten interconnected domains.
The panel is built by buildClimateConsiderations() and uses the property’s elevation,
coast distance, soil type, waterway proximity, topographic position, and urban surface classification
to tailor relevance ratings for each domain.
All projections are drawn from peer-reviewed literature and authoritative Danish/Nordic sources. Confidence levels follow IPCC terminology: high confidence (robust evidence, high agreement), medium confidence (limited evidence or mixed agreement), low confidence (incomplete evidence). Severity ratings per consequence use four levels: minor, moderate, severe, and critical.
1. Sea Level Rise
Denmark faces 0.5–1.6m of sea level rise by 2100 depending on emissions, with southern regions most vulnerable due to land subsidence. DMI projections exceed IPCC global means because they account for regional North Sea and Baltic dynamics.
| Decade | SSP1-2.6 | SSP2-4.5 | SSP5-8.5 | Low confidence |
|---|---|---|---|---|
| 2050 | +0.17 m | +0.22 m | +0.27 m | +0.40 m |
| 2060 | +0.24 m | +0.32 m | +0.40 m | +0.62 m |
| 2070 | +0.31 m | +0.42 m | +0.54 m | +0.88 m |
| 2080 | +0.38 m | +0.50 m | +0.65 m | +1.10 m |
| 2090 | +0.44 m | +0.57 m | +0.75 m | +1.35 m |
| 2100 | +0.50 m | +0.64 m | +0.85 m | +1.60 m |
Regional factors: Greenland ice melt reduces local sea level via gravitational fingerprinting (Denmark receives only 0.2–0.5 mm/yr per 1 mm/yr global from Greenland), but Antarctic melt produces above-average SLR in the Northern Hemisphere. Northern Denmark benefits from post-glacial uplift (1–2 mm/yr); southern Denmark (Lolland-Falster, South Jutland) experiences slight subsidence.
Impact thresholds: At +0.5m, storm surges reach ~50% more properties and 18,100 ha face permanent flooding. At +1.0m, 72,700 ha flooded and ~2% of Danish homes at direct risk. At +1.5m+, Lolland-Falster, Amager, and western Jutland require major defences or managed retreat. Coastal wetland loss: 14.3% by 2070, 44.7% by 2120.
2. AMOC (Atlantic Meridional Overturning Circulation)
The AMOC — the ocean conveyor bringing warmth to northwestern Europe — has been weakening over the past century. Denmark sits directly in the AMOC impact zone, making this the highest-consequence risk factor for the region.
| Study | Finding | Source |
|---|---|---|
| Ditlevsen & Ditlevsen (2023) | Collapse projected 2025–2095, central ~2057 | Nature Communications |
| Boers (2021) | Early-warning signals in 8 AMOC indices | Nature Climate Change |
| Weijer et al. (2025) | AMOC resilient across 34 CMIP6 models | Nature |
| Nordic Council (2026) | 70% collapse probability (high emissions) | TemaNord 2026:504 |
If weakened (20–30% by 2050): Modest cooling partially offsetting global warming; slightly more severe winters; minor agricultural adjustment.
If collapsed: 5–10°C winter cooling in Denmark within decades; sea ice extending to the Kattegat and Baltic; growing seasons contract dramatically; current crop varieties (wheat, barley, rapeseed) become unviable; Denmark’s winter climate comparable to interior Alaska/northern Canada. Energy demand for heating would surge. This would occur against a backdrop of continued global warming, creating a stark regional anomaly.
3. Extreme Weather & Precipitation
Denmark faces a triple threat: rain from above, sea from the coast, and groundwater from below — all intensifying. Temperature has risen 1.8°C over 50 years (~0.5°C per decade, faster than global average).
| Metric | Projected change | Source |
|---|---|---|
| Annual precipitation | +8% by 2041–2070 | DMI Klimaatlas |
| Cloudburst frequency | +31% | DMI/SVK |
| Days >20mm rain (winter) | +40% | DMI Klimaatlas |
| Extreme hourly intensity | +15–30% | SVK climate factors |
| West coast storm surge | +0.2–0.5m by 2100 | Copernicus |
Compound events are the critical concern: simultaneous SLR + storm surge + river flooding + heavy rainfall. These are poorly modelled individually but devastating in combination. Economic damage without adaptation: DKK 72 billion over 10 years, DKK 262 billion over 50 years (DTU/CIP 2024).
Groundwater rise: ~440,000 year-round Danish homes threatened by combined water hazards (CONCITO). Not covered by standard insurance; government only recently addressing it (November 2024 proposal).
4. Food Security & Agriculture
Denmark is a major agricultural nation (~61% farmland). Under moderate warming (1.5–2°C global), Danish agriculture benefits: longer growing seasons (+18 days over 50 years already), CO2 fertilisation boosting C3 crops +5–18%, and new varieties becoming viable (maize, sunflower, wine grapes).
Under higher warming (3–4°C), effects turn mixed-to-negative: heat stress during critical growth, new pests migrating north, extreme precipitation disrupting planting/harvest, and summer soil moisture deficits. Under AMOC collapse, Danish agriculture faces existential crisis — growing season contracts dramatically and current crops become unviable.
Denmark imports ~25% of food calories. Global breadbasket failures (simultaneous droughts in multiple grain regions) directly affect Danish food prices. The 2022 wheat price spike (+50–100%) after Russia-Ukraine previewed this pathway.
Olesen et al. (2011); Aarhus University (2024); Nordic Council (2026); ClimateChangePost5. Insurance & Property Markets
Denmark operates a unique solidarity-based scheme (Naturskadeordningen) funded by DKK 30/year from every fire-insured individual, governed by Naturskaderadet. Coverage triggers when water level exceeds a 20-year return period, covering direct damage to buildings and contents.
Properties at risk projected to nearly double from current 0.9–1.2% to ~2% by 2071. Coastal property premium erosion beginning in highest-risk areas. No systematic climate risk disclosure requirement exists in Danish property transactions (as of 2025). Globally, climate-driven uninsurability is accelerating (California, Queensland, Florida).
By 2100: The insurance scheme likely needs fundamental restructuring. Some areas may become effectively uninsurable under high-emission scenarios. Significant property value redistribution expected from coastal/low-lying to inland/elevated locations.
Naturskaderadet; WTW (2023); EIOPA/ECB (2024); ClimateChangePost6. Government & Infrastructure Resilience
Denmark ranks #1 on the Climate Change Performance Index (2025) with very strong institutional capacity, low corruption, and consistent multi-party consensus. Key initiatives:
| Initiative | Budget / Status |
|---|---|
| Climate Adaptation Plan 1 | DKK 1.3 bn for coastal/urban protection |
| West coast programme | EUR 204m/year for 110 km beach nourishment |
| Lynetteholmen (Copenhagen) | ~EUR 2.7 bn; storm surge protection to 3.6m |
| Holmene (Hvidovre) | ~EUR 425m; 9 islets built 5.5m above sea level |
| Municipal adaptation plans | All 98 municipalities; quality uneven |
Implementation gap: Plans exist but execution lags. Only 25% of municipal plans mention nature-based solutions. Denmark has far less coastal defence heritage than the Netherlands. About 30% of Denmark’s area is vulnerable to flooding from storm surges, cloudbursts, and rising groundwater. Critical infrastructure at risk includes low-lying rail corridors (Storebælt/Øresund links), hospitals, substations, and combined sewer systems.
7. Climate Tipping Points
Armstrong McKay et al. (2022) identified 16 global tipping elements. Five are already above their minimum threshold at current ~1.2°C warming: Greenland Ice Sheet, West Antarctic Ice Sheet, tropical coral reefs, Labrador-Irminger Sea convection, and abrupt permafrost thaw.
| Tipping element | Threshold | Timescale | Denmark relevance |
|---|---|---|---|
| AMOC collapse | 1.4–8.0°C | Decades | Critical |
| Greenland Ice Sheet | 0.8–3.0°C | Centuries–millennia | High (SLR) |
| West Antarctic Ice Sheet | 1.0–3.0°C | Centuries–millennia | High (SLR) |
| Boreal forest shift | 1.4–5.0°C | Decades–century | Medium |
| Permafrost (abrupt thaw) | 1.0–2.3°C | Decades | Medium (indirect) |
| Barents Sea ice | 1.6–2.0°C | Decades | Medium |
Tipping cascades: The critical concern is not individual tipping points but cascading interactions. Greenland melt → freshwater → AMOC weakening → further melt (positive feedback). Permafrost thaw → methane/CO2 → warming → more thaw (carbon feedback). A 2025 study found that under current policies, Amazon dieback and permafrost thaw “modestly amplify” the probability of triggering other tipping points. By 2100, 3–6 elements likely committed under SSP2-4.5.
8. Health & Livability
Denmark avoids the worst heat impacts but faces genuine and growing risks:
- Heat stress: Aging population (25% over 65 by 2050) increases vulnerability. Limited residential air conditioning. Urban heat island effect in Copenhagen. Under SSP5-8.5, regular 35°C+ events by 2100.
- Tick-borne disease: TBE cases with presumed Danish infection rising (17 in 2024, up from 13 in 2023). Geographic spread from Bornholm to North Zealand and first Jutland case. Lyme disease incidence increasing with tick range expansion.
- Air quality: Wildfire smoke transport from southern Europe intensifying. 2025 summer: highest fire emissions in 23 years of GFAS data in Greece/Turkey/Iberia. Ozone formation increases with temperature.
- Mental health: Climate anxiety growing, especially among young people. Flooding events cause PTSD, anxiety, depression. Property value uncertainty creates financial stress.
9. War & Geopolitical Risk
Climate change acts as a “threat multiplier” that amplifies geopolitical instability. Denmark’s position as an Arctic nation (via Greenland), NATO member, EU state, and small open economy creates distinctive indirect climate-security risks.
Arctic geopolitics: Denmark committed DKK 42 billion to Arctic defence (2025–2026), exceeding 3% of GDP. The Northern Sea Route is projected navigable 3–6 months/year by 2050 and potentially year-round by 2100, making the Arctic a primary theatre of great-power competition. Greenland holds 25 of 34 EU critical minerals and ~$186 billion in extractable resources.
Climate migration: World Bank projects 216 million internal climate migrants by 2050. Research shows climate conditions are “weak predictors” of asylum migration directly (Abel et al. 2021), but climate → conflict → displacement pathways are significant (Abel et al. 2019). Under SSP5-8.5 by 2100, potentially 500M–1B+ people in uninhabitable zones globally.
Nuclear risk: Climate-amplified tensions (India-Pakistan water disputes, Arctic competition) increase nuclear conflict probability. Xia et al. (2022, Nature Food) estimate a regional nuclear exchange could cause global famine affecting over 2 billion people. A regional exchange could cool Earth 2–5°C for a decade.
Infrastructure security: Baltic undersea cables cut in 2024. Denmark’s energy grid, data infrastructure, and supply chains face increasing hybrid/cyber threats in a more unstable world.
NATO (2024); World Bank (2021); Abel et al. (2019, 2021); Xia et al. (2022); CSIS (2025); Wilson Center (2025)10. Cost of Living
Climate change affects Danish household finances through at least ten channels. The aggregate additional cost is projected to grow from ~DKK 5,000–15,000/year per household in the 2030s to DKK 25,000–80,000+/year by 2100 under moderate-to-high emission scenarios. Low-lying, coastal, and clay-soil properties face significantly higher costs — directly reinforcing Saferland’s scoring logic.
| Cost channel | Key driver | By 2050 | By 2100 |
|---|---|---|---|
| Energy | AMOC heating / cooling demand / volatility | +DKK 0–5k | +DKK 2–40k |
| Food | Global crop failures, import prices | +DKK 5–12k | +DKK 3–25k |
| Water & sewage | Infrastructure upgrades, climate levies | +DKK 1–3k | +DKK 3–8k |
| Property tax | Municipal adaptation levies | +DKK 2–5k | +DKK 5–15k |
| Insurance | Scheme restructuring, risk pricing | +DKK 1–3k | +DKK 5–20k |
| Construction | Climate building codes, flood-proofing | +DKK 2–5k | +DKK 3–10k |
| Healthcare | Heat/vector/mental health burden | +DKK 0–2k | +DKK 1–5k |
| Adaptation | Personal flood protection, drainage | +DKK 2–8k | +DKK 5–15k |
Food prices have already risen 32% since 2021 (twice general CPI). The 2022 energy crisis (electricity spot prices hitting DKK 7–8/kWh, 3× baseline) previewed what climate-driven supply disruptions look like. Under AMOC collapse, heating demand could double, creating an energy cost crisis of DKK 15,000–30,000+/year per household.
Location-dependent relevance
The Regional Climate Guide adjusts relevance ratings based on the analysed property’s characteristics:
| Domain | Higher relevance when… |
|---|---|
| Sea Level Rise | Low elevation (<5m) or close to coast (<5km) |
| AMOC | Universally high for all Danish locations |
| Extreme Weather | Low elevation, clay soil, or topographic depression |
| Food Security | Universally moderate; slightly higher in rural areas |
| Insurance | Low elevation, coastal, or flood-prone locations |
| Government Response | Universally moderate |
| Tipping Points | Universally high (all Denmark in AMOC zone) |
| Health | Urban areas (heat island), low elevation (flooding stress) |
| War & Conflict | Near critical infrastructure (ports, military, cables) |
| Cost of Living | Low elevation, coastal, clay soil (higher adaptation costs) |
Key References
Danish standards & authorities
- Spildevandskomiteen (SVK) Skrift 27 (2014): Funktionspraksis for afløbssystemer under regn. The authoritative Danish sewer design standard; defines return-period requirements and rational method φ-coefficients.
- SVK Skrift 29 (2006): Forventede ændringer i ekstremregn som følge af klimaudviklinger. Climate factors for future rainfall intensity.
- SVK Skrift 30 (2014): Dimensionering af LAR-anlæg. Design of local stormwater management (SUDS/LAR) systems.
- DMI Technical Report 15-01 (Ditlevsen et al., 2018): Extreme sea levels in Danish waters. 100-year return-period surge heights.
- Kystdirektoratet: Kysternes tilstand (annual). Coastal erosion monitoring and nourishment data.
- GEUS: Jordartskort 1:200,000. National geological surface map of Denmark.
- Styrelsen for Dataforsyning og Infrastruktur: Danmarks Højdemodel (DHM). National 0.4m LiDAR DEM and derived flood products.
- Geodatastyrelsen: DVR90 (Dansk Vertikal Reference 1990). National vertical datum definition.
IPCC & international
- IPCC AR6 WG1 Chapter 9 (Fox-Kemper et al., 2021): Ocean, cryosphere and sea level change. Global and regional SLR projections.
- Garbe et al. (2020): The hysteresis of the Antarctic Ice Sheet. Nature Climate Change 10, 758–763. WAIS tipping point threshold analysis.
- Bamber et al. (2019): Ice sheet contributions to future sea-level rise from structured expert judgment. PNAS 116(23), 11195–11200.
- Hansen, J. et al. (2023): Global warming in the pipeline. Oxford Open Climate Change, 3(1), kgad008. High-end SLR and climate sensitivity arguments.
- Crawford, A.J. et al. (2024): The West Antarctic Ice Sheet may not be vulnerable to marine ice cliff instability during the 21st century. Science Advances, 10(34).
AMOC
- Ditlevsen, P. & Ditlevsen, S. (2023): Warning of a forthcoming collapse of the Atlantic meridional overturning circulation. Nature Communications, 14, 4254.
- Boers, N. (2021): Observation-based early-warning signals for a collapse of the AMOC. Nature Climate Change, 11, 680–688.
- Weijer, W. et al. (2025): Continued Atlantic overturning circulation even under climate extremes. Nature, 638, 987–994.
- Nordic Council of Ministers (2026): A Nordic Perspective on AMOC Tipping. TemaNord 2026:504.
Tipping points & cascades
- Armstrong McKay, D.I. et al. (2022): Exceeding 1.5°C global warming could trigger multiple climate tipping points. Science, 377, 1171–1175.
- Lenton, T.M. et al. (2019): Climate tipping points — too risky to bet against. Nature, 575, 592–595.
- Wunderling, N. et al. (2025): High probability of triggering climate tipping points under current policies modestly amplified by Amazon dieback and permafrost thaw. Earth System Dynamics, 16, 565.
Agriculture & food security
- Olesen, J.E. et al. (2011): Impacts and adaptation of European crop production systems to climate change. European Journal of Agronomy, 34(2), 96–112.
- Aarhus University (2024): How Danish agriculture can adapt to future climate change.
- Climate Central (2024): Climate Change and Food Prices.
- IFRO/University of Copenhagen (2024): Food security in Denmark: A data-driven assessment.
Insurance & property
- Naturskaderadet: Storm surge and flooding compensation procedures. danishnaturalhazardscouncil.dk.
- WTW (2023): The storm surge has uncovered major gaps in insurance coverage. Insights paper.
- EIOPA/ECB (2024): Proposals for EU-level natural catastrophe insurance scheme.
- Nature Climate Change (2026): Prospects and challenges of risk-based insurance pricing for disaster adaptation.
Government & adaptation
- Klimatilpasning.dk: National Adaptation Strategy and Plan documentation.
- State of Green (2024): Danish Government presents plan to ramp up climate adaptation.
- Clean Energy Wire (2025): Denmark keeps on dithering over climate adaptation plans.
- CCPI (2025): Climate Change Performance Index country ranking.
- Copenhagen Post (2026): Government to spend 15 billion DKK on coastal protection to prevent flooding.
Health & livability
- SSI Denmark (2024): TBE Report 2024. Statens Serum Institut.
- Copernicus (2025): Air Quality Challenges in 2025: Europe’s Summer of Smoke, Dust and Ozone.
- EEA (2024): Denmark — air pollution country fact sheet 2024.
- Bjerager, M. et al. (2024): Impacts of Sea Level Rise on Danish Coastal Wetlands. Environmental Management.
Geopolitics & conflict
- NATO (2024): Climate Change and Security Impact Assessment 2024.
- World Bank (2021): Groundswell Part 2: Acting on Internal Climate Migration.
- Abel, G. et al. (2019): Climate, conflict and forced migration. Global Environmental Change, 54, 239–249.
- Abel, G. et al. (2021): Climatic conditions are weak predictors of asylum migration. Nature Communications, 12, 2067.
- Xia, L. et al. (2022): Global food insecurity and famine from reduced crop, marine fishery and livestock production due to climate disruption from nuclear war soot injection. Nature Food, 3, 586–596.
- CSIS (2025): Greenland, Rare Earths, and Arctic Security.
- Wilson Center (2025): Risky Game: Hybrid Attack on Baltic Undersea Cables.
- IMF (2024): Climate Variability and Worldwide Migration. Working Paper 2024/058.
Economics & cost of living
- Danmarks Nationalbank (2023): Denmark risks a period of energy price fluctuations.
- Danmarks Nationalbank (2025): Global factors are driving high food prices in Denmark and abroad.
- Danmarks Nationalbank (2025): Global temperatures and inflation: More volatile, less homogeneous inflation pressures across countries.
- ECB (2022): Schnabel, I. A new age of energy inflation: climateflation, fossilflation and greenflation.
- EESC (2023): The cost of climate change on households and families in the EU.
- Housing Denmark (2024): Switching to Heat Pumps.
- CONCITO: Combined water hazards assessment for Danish properties.
Hydrology & geotechnics
- Fredericia, J. (1990): Saturated hydraulic conductivity of clayey tills and the role of fractures. Nordic Hydrology, 21(2), 119–132. Key paper on Danish moræneler field-scale K values.
- Merz et al. (2010): Assessment of economic flood damage. Natural Hazards and Earth System Sciences, 10, 1697–1724. Flood damage–distance relationships.
- Vestol et al. (2019): NKG2016LU: a new land uplift model for Fennoscandia and the Baltic region. Journal of Geodesy, 93, 1759–1779.
- Greve et al. (2014): Estimating peat soil loss in Denmark over the past 30 years. Aarhus University / GEUS.
- Weiss, A. (2001): Topographic Position and Landforms Analysis. ESRI User Conference poster. Foundational TPI methodology.
Data APIs
- Open-Meteo: Free elevation API using Copernicus DEM / SRTM blend. ~30m horizontal resolution.
- OpenStreetMap / Overpass API: Crowdsourced geospatial data for coastline, waterways, and land use.
- AWS Terrarium Tiles: RGB-encoded elevation tiles derived from SRTM/ASTER. Open data.
- GEUS WMS: Geological Survey of Denmark — soil type map via OGC WMS GetMap/GetFeatureInfo.
- Dataforsyningen: Danish government geospatial data portal — DHM flood zones, hillshade, contours via OGC WMS.