Responsible Development on Coasts and Islands: An Underwriting Input

Coral reefs cover less than 1% of the ocean floor yet support at least a quarter of all marine species, with an estimated value of goods and services of around US$2.7 trillion a year (UNEP). On the coasts and small islands where prime hospitality and residential capital concentrates, this natural capital is not a backdrop. It is the asset. Degrade the shoreline, the reef, the mangrove or the fresh-water aquifer, and the location stops being worth what the underwriting assumed.

What follows is the operating frame Victaura applies to its positions on Zanzibar, Gili Air, Lake Como and Ras Al Khaimah, set against the climate, regulatory and disclosure standards the institutional buyer now expects documented. Technical, jurisdictional, conservative by design. Not a claim about certifications we do not hold.

The exposure asset class faces#

Sea level rise is no longer a long-horizon abstraction. IPCC AR6 (Working Group I, 2021) projects global mean sea level rise of 0.33 to 0.62 metres by 2100 under the low-emissions SSP1-2.6 scenario, and 0.63 to 1.01 metres under SSP5-8.5, relative to 1995-2014. The current rate of rise is approximately 3.7 mm per year (2006-2018), close to three times the 1.3 mm per year recorded between 1901 and 1971. AR6 also retains a low-likelihood branch in which marine ice-sheet instability contributes meaningfully more, with the high-end above 1.5 metres by 2100. For an asset with a 30-to-50 year operating horizon, the question is no longer whether sea level rises, but where, how fast and against what setback discipline.

The regional signal is material. In the Western Indian Ocean, sea level is rising at approximately 3.5 mm per year, roughly 4% above the global mean. On the east coast of Unguja, Zanzibar, remote-sensing analysis of Landsat imagery between 1990 and 2020 measured a shoreline retreat of approximately 15.56 metres per year, with model projections of 25.65 metres per year by 2040 (Journal of Sea Research, 2024). These describe specific east-coast segments. Nungwi, on the northern tip, has materially different bathymetry, tidal range and reef-platform geometry. The implication is not that Zanzibar is uninvestable. The parcel matters, the orientation matters, and a generic destination thesis is not underwriting.

For Indonesia, the projection is similar in scale and different in geometry. Indonesian researchers, using IPCC SRES scenarios, projected sea level rise of 13 to 35 centimetres by 2050 along the Lombok coastline. The shock vector for the Gili archipelago, however, is less about absolute sea level and more about coral mortality. The De Clippele et al. study (University of Glasgow, with WWF Indonesia and the Indonesian Ministry of Maritime Affairs and Fisheries) projects Gili Matra among the twelve Indonesian marine protected areas facing annual severe bleaching from around 2026, expanding to more than half of Indonesia's 161 MPAs by 2044. A reef that bleaches annually loses the geomorphic function that protects the shoreline behind it. The asset class is exposed not only to rising water but to the loss of the natural breakwater that has kept the water at bay.

This is the underwriting frame. Climate exposure is not an externality netted out with a discounted insurance premium. It is an input into FAR, into setback, into structural specification, into water and energy planning, into the timeline over which the operator can credibly hold and operate the asset.

The permitting frame: jurisdictional review#

Permitting is where the responsible-development thesis is tested. Each of the four jurisdictions in which Victaura, through Greystone B.V., holds positions imposes a distinct environmental review regime. Reading them side by side is the first diligence step.

*Indonesia: AMDAL. Analisis Mengenai Dampak Lingkungan is grounded in Law No. 32 of 2009, as amended by the Job Creation Law (Law No. 11 of 2020) and Government Regulation No. 22 of 2021. AMDAL is mandatory for projects with significant environmental impact, including coastal construction, dredging, reclamation and hospitality at scale. The process involves a Terms of Reference (KA-ANDAL), the ANDAL technical analysis, the Environmental Management Plan (RKL-RPL), and a ten business-day public consultation window. Indicative timelines for a clean cycle run to twelve to eighteen months. Failure mode: a project that begins construction before the Persetujuan Lingkungan* is issued is, in legal grammar, unauthorised. The remediation cost is not a fine. It is the asset.

*Tanzania: NEMC.* The National Environment Management Council administers EIA under the Environmental Management Act 2004 and the EIA & Audit Regulations 2005. The nine-step process moves from registration, screening and scoping through the EIS, the public hearing and the Technical Review Committee. Statutory review window: 60 days after report submission. In practice, a Zanzibar coastal project completes in nine to fifteen months. The certificate is issued by the responsible Minister on NEMC recommendation, only on verified implementation of mitigation conditions. The Zanzibar Environmental Management Act 2015 operates in parallel for projects under Strategic Investment Status. Failure mode: conditions signed but not operationally implemented (waste-water treatment commissioned on paper but not running at design capacity) become enforcement triggers downstream.

*Italy: autorizzazione paesaggistica. On Lake Como, every intervention within the 300-metre landscape band from the shoreline (D.Lgs 42/2004 Art. 142(1)(b)) is subject to landscape authorisation under Article 146. Ordinary authorisation: the competent administration transmits the file to the Soprintendenza within 40 days, which issues its binding opinion within 45 days; the authorisation is valid five years. Simplified authorisation, for interventions of minor significance defined by Presidential Decree 31/2017, runs to 20 days. The Lombardy Piano Paesaggistico Regionale adds site-specific tutela for the insubric lakes. Failure mode: starting work without authorisation triggers accertamento di compatibilità paesaggistica* under Article 167, a 90-day review. Non-compatibility means restoration to the pre-existing state at the developer's expense.

United Arab Emirates: Federal Decree-Law No. 11 of 2024. Issued 28 August 2024 and effective from 30 May 2025, the law makes the UAE the first MENA jurisdiction with a binding national climate framework. It applies to all public and private sector entities, including free zone entities, with no minimum thresholds. Entities must measure, report and manage greenhouse gas emissions using approved standards, submit to third-party verification, and maintain a five-year record. For developers on Al Marjan Island and other RAK freehold zones, operational carbon disclosure becomes a regulatory obligation, not a voluntary signal. Penalties range from AED 50,000 to AED 2,000,000, doubled for repeat violations within two years. This sits alongside the EIA regime administered by the federal Ministry of Climate Change and Environment and the RAK Environment Protection and Development Authority (EPDA).

Light footprint as design principle#

Light footprint is not an aesthetic. It is a sequence of measurable design choices: floor-area ratio held below the carrying capacity of the parcel, mangrove and reef buffers treated as inviolable, set-back lines drawn from the highest measured spring tide rather than the average, foundation systems specified for storm-surge return periods consistent with the building's operating horizon. These choices are the difference between an asset that operates for fifty years and one that requires retrofit within fifteen.

FAR ceilings are the first protection. On the Gili archipelago, the absence of internal combustion vehicles and high-rise zoning is not a policy preference. It is the carrying capacity of a finite landmass with finite fresh-water aquifers, codified into local practice. A villa scheme that respects an effective FAR consistent with the historical low-density character is, by construction, less exposed to the second-order failures (sewage overflow, fresh-water depletion, sand-mining-induced erosion) that have degraded comparable destinations elsewhere in the region.

Mangrove and reef buffers carry an engineering function as well as a biodiversity function. A 100-metre intact mangrove fringe reduces wave energy reaching the shoreline by 13 to 66% depending on canopy density and tidal stage (Nature Communications, 2018). The fringe traps sediment, stabilises the coastline against the kind of retreat measured on east Unguja, and sequesters carbon at densities four to five times those of terrestrial tropical forest. Reef-friendly construction protocols add to this: anchor placement that avoids living coral, sediment-plume management during marine works, no-discharge zones within reef-flat distance, motorised-watercraft restrictions. Each adds cost in construction and protects revenue in operation. The cost of a reef-friendly mooring system is a small fraction of the cost of a closed dive operation.

Water and energy: the real constraint#

On a small island, the binding constraint is rarely land. It is fresh water and electrical capacity. The Gili archipelago has no piped municipal water supply. Operations rely on rainwater harvesting, brackish-water boreholes drawn from a thin lens above seawater, and reverse-osmosis desalination. Over-extraction induces saltwater intrusion that takes decades to reverse. A development that designs for hotel-style consumption (300 to 700 litres per guest-day in the international standard) without a desalination plan is designing for failure.

The EDGE standard (IFC, World Bank Group) sets a useful baseline. EDGE Certified requires a minimum projected reduction of 20% in energy use, water use and embodied energy in materials, benchmarked against a standard local building. EDGE Advanced raises the energy reduction to 40%. Used in over 170 countries, EDGE is the framework most directly applicable to emerging-market coastal hospitality, because the local-benchmark methodology adapts to climate zone and grid carbon intensity. We do not currently hold EDGE certification on operating assets. We design to the EDGE 20-20-20 envelope as the internal floor and document where we exceed it. Claiming a certification that is not issued is a misrepresentation we will not make.

On the energy side, the grid limit is binding before the carbon limit is. PLN supplies the Gili islands via submarine cable from Lombok. Capacity is finite, diesel back-up runs in peak season. Rooftop solar with battery storage sized to the daily evening load reduces the marginal grid call and the single-point-of-failure risk during cable maintenance windows. On Zanzibar, ZECO supply remains constrained on the east coast: same logic. On Lake Como the question inverts (peak load is winter heating, not summer cooling, and historic-villa restoration carries embodied-carbon and thermal-envelope constraints that no off-the-shelf certification fully captures). The principle holds: design to a measurable envelope, document the calculation, disclose the assumption.

Embodied carbon is the third leg. Cement is responsible for approximately 7 to 8% of global CO2 emissions. A coastal villa scheme built on imported Portland cement with steel shipped through sea freight has an embodied-carbon footprint that dwarfs its first twenty years of operational emissions. Substituting locally sourced lime mortars and coral-stone (where harvested under permit from quarried, not living, sources) reduces both the carbon line and the supply-chain risk line. The mortar at Stone Town has stood for two centuries on lime, not Portland cement. The technical evidence is in the masonry.

Mangrove restoration economics#

Mangroves are the most carbon-dense ecosystem on the planet. Per hectare, an intact mangrove stand stores three to five times the carbon of an equivalent tropical rainforest, largely in the anaerobic peat below the root zone. For the operator on a coast where mangroves have been degraded, restoration is not a cost line. It is a coastal-protection line, a community-engagement line, and (with discipline) a carbon-revenue line layered together.

The economics are measurable. A 2020 global analysis (Ecological Economics) found conservation of remaining mangroves feasible at carbon prices between US$3 and US$13 per tCO2 for 90% of stock. Restoration of deforested area at US$4.5 to US$18 per tCO2 for 90% of the deforested area. A 2025 Nature Communications analysis puts the global benefit-cost ratio of mangrove restoration at 6.35 to 15.0, with cumulative net gains of US$231 to US$725 billion against US$40 to US$52 billion in investment over two decades. Verified Carbon Standard (Verra VCS) and Plan Vivo are the operating frameworks: projects in Madagascar (Tahiry Honko), Kenya (Mikoko Pamoja, the first Plan Vivo blue carbon project) and increasingly Indonesia have demonstrated the credit-issuance process is operable, with VCS+CCB blue carbon clearing US$15-35 per tCO2 in 2024-2025. The operator's own offset claim is a separate question, one Victaura does not currently make in public communications.

The community line is not optional. Mangrove restoration without local livelihood integration tends to fail within five years. The literature is consistent. Programmes that pay community members to plant, monitor and police restoration sites, with carbon revenue underwriting the wage line, are the programmes that survive. On Zanzibar, where mangrove cover declined materially across Chwaka Bay and Menai Bay between 1973 and 2020, the restoration runway is wide and the institutional partner geometry (IUCN, WWF, Tanzania Forest Services, ZAWA) is in place. The operating question is whether the scheme is designed with that partnership as a load-bearing element or as a CSR addendum.

The supply chain question#

A coastal villa is the sum of what was shipped to the site. Cement, rebar, glass, marine plywood, sanitary ware, tile, fit-out, HVAC, technical wiring: each line carries an embodied-carbon footprint, a sea-freight footprint, and a counterparty risk. Local sourcing has technical limits. Coral-stone masonry, lime mortars, hardwood frames, woven palm and rattan finishes are local strengths in Zanzibar and Indonesia with deep craft traditions. Glass and steel structural elements typically are not. The credible model is segmentation: structural systems imported from optimised supply chains, finish and craft layer sourced within a defined regional radius (frequently 100 to 300 kilometres for sustainably harvested timber and stone).

Sea freight has its own emissions profile and its own disruption profile. The Red Sea disruption of 2024-2025, the Iran conflict's spillover into Strait of Hormuz shipping insurance premia in 2026, and the structural rise in container rates on Asia-Mediterranean and Asia-East Africa routes mean the supply-chain plan that worked in 2019 is not the plan that works in 2026. Contingency on imported materials must be sized to current freight volatility, not historical means. We hold 90 to 120 day buffer stock on critical-path materials at site or regional warehouse, and have revised cost contingency on imported structural systems upward by approximately 8 to 12% against 2023 baselines. On cement specifically, replacing a portion of Portland with locally available pozzolanic substitutes (volcanic ash on Bali and Lombok, coral-derived limes on Zanzibar) is technically possible and has historical precedent, with trade-offs in curing time and quality control under tropical humidity. The decision is project-specific. The point is that it is made deliberately and documented, not defaulted because that is what the foreign architect specified by habit.

The operator advantage#

The structural difference between an operator and a flip-and-exit developer is time horizon. A scheme designed to be built, sold and exited within 24 to 36 months has an incentive structure that rewards visible finish and discounts non-visible system integrity. A scheme designed to be built, operated and held for 15 to 30 years has the opposite incentive. The operator pays the operating cost of every design shortcut. The flipper does not.

Responsible development is, in practice, an operator's discipline. Mangrove restoration takes seven to fifteen years to mature into measurable coastal-protection function. Reef-friendly mooring systems pay back through preserved dive-tourism revenue over a multi-year horizon. Water systems designed to the desalination-plus-rainwater envelope cost more in year one and dramatically less in year ten when the borehole salinises. None of these decisions look optimal on a 24-month exit underwriting. All of them look optimal on a 20-year hold.

Skin-in-the-game disclosure. Victaura operates as the asset-management arm of Greystone B.V. (Netherlands), which holds active commercial positions in each of the four jurisdictions discussed: Lake Como, Zanzibar (Nungwi area, Secret Zanzibar), Gili Air (Gili Air Villas boutique hotel and freehold villas), and Ras Al Khaimah (Al Marjan Island corridor). Readers should assume that commentary on these markets may benefit Greystone's existing positions. This document is classified as marketing material under MiFID II Article 24(3) and is not investment advice.

Disclosure framework: TNFD, GRESB, EDGE#

Institutional capital reads three frameworks first. The Taskforce on Nature-related Financial Disclosures (TNFD) released its final recommendations in September 2023. By the start of 2025, over 500 organisations across 54 jurisdictions, representing US$6.5 trillion in market capitalisation and US$17.7 trillion in financial-institution AUM, had committed to TNFD-aligned reporting. In 2025, the TNFD signed an MoU with the IFRS Foundation, aligning the framework with the ISSB. For real estate developers in nature-sensitive locations, the LEAP approach (Locate, Evaluate, Assess, Prepare) is becoming the expected diligence trail.

GRESB sets the real-estate operating benchmark. The 2025 GRESB Real Estate Assessment received 2,382 submissions from 1,002 fund managers, with standing investments scoring 79 on average (up 3.1 points year on year). Energy data coverage exceeded 75% globally for the second consecutive year. The share of real-estate entities with net-zero policies reached 81.5%, up from 72.4% in 2023. The 2025 cycle introduced new metrics for embodied carbon, biodiversity and certifications, and a Residential Component for the first time. GRESB is the closest thing to a standardised peer comparison the asset class has.

EDGE remains the most operable certification in emerging coastal markets. Calibrated to the local benchmark in each climate zone, it adapts where LEED and BREEAM struggle. EDGE Certified, EDGE Advanced and EDGE Zero Carbon form a three-tier ladder. We design to the certified envelope as the internal floor on new-build coastal projects. We do not currently hold the certification on operating assets and will disclose where and when that changes.

The pattern across these frameworks is the same. They reward operators that publish assumptions and disclose conflicts. They penalise opacity. Institutional capital evaluating branded-residence and coastal-resort schemes runs its due diligence against these frameworks before running the yield calculation. A project that cannot answer TNFD LEAP questions on biodiversity, water and nature dependencies fails diligence before the financial model is opened.

What this means for the buyer: real diligence questions#

For the family office, institutional allocator or principal advisor evaluating a coastal or island development, the diligence question is no longer whether it is responsible. It is whether the responsibility is documented, technical and verifiable. The questions that matter are operational, not narrative.

*Permitting: has the AMDAL / NEMC / autorizzazione paesaggistica / EPDA EIA been issued, and have its conditions been operationally implemented or only signed?* The signed version is paper. The operational version is the asset. Ask for the most recent monitoring report under RKL-RPL or equivalent.

Water and energy: what is the designed per-guest-day water consumption, the desalination back-up, the rooftop-solar plus battery sizing, and how was the embodied-carbon line in the bill of materials calculated? Round numbers without method are marketing. The calculations exist or they do not.

Mangrove and reef: is the restoration programme funded as an operating line in the asset's pro-forma, or as a CSR addendum? Is the carbon credit revenue (if any) flowing to community wage support, to asset-level offset claims, or both? The answer changes how the claim should be read.

Supply chain: what percentage of the bill of materials is sourced within a defined regional radius, what is the freight contingency, what is the cement substitution strategy? The percentage exists. Ask for it.

Disclosure: is the operator publishing TNFD LEAP, GRESB submission, EDGE design envelope? If not, why not? Operators that decline to disclose at the institutional standard are operators not being read by institutional capital.

The institutional partner the segment now selects is the operator that says less and discloses more. Numbers triangulated, conflicts named, methodology published. That is the standard. This document is published with that standard in mind.