**7. Discussion**

#### *7.1. Resource E*ffi*ciency in the Tourism Sector: Maintenance and Replacement Requirements*

The role of tourism for A&B is significant, accounting for approximately 80% of the country's GDP [3], and remains the most productive sector in the constant reconstruction of the economy after a crisis. Before the economic recession in 2008, the island's economic activity experienced positive growth rates of GDP, with 12% recorded in 2006 and 9% in 2007 [9]. This growth was in direct response to both the tourism and construction sectors that function as drivers of income and employment generation [68]. Apergis and Payne [69] studied the causal relationship between tourism and economic growth for nine Caribbean islands from 1995–2007 and found a bidirectional causality relationship between tourism and economic growth from both a long-term and short-term perspective.

Construction material production is a major driver of environmental and economic burdens, exacerbated in a SIDS like A&B which imports much of its construction materials, and so it is imperative to utilize the existing stock and plan future stock accumulation in a way that reduces demands for further inflows. Material extraction and imports are required to an extent for improving wellbeing and supporting the economy, and the inflows required for stock expansion to meet growing societal and economic demands is considered a characteristic of development [14,70]. Inflows for these ends may plateau and eventually perhaps even decline once material stocks reach a level of su fficiency or "saturation" [60,71,72]. Policy towards lowering this ultimate level using resource e fficiency measures to "get more service from less material" [73], i.e., to minimize the need to further accumulate stocks, would be of high priority, especially in the context of a SIDS which, as an importer rather than a producer of materials, has little control over supply-side technical resource e fficiency measures [73].

In this regard, our results show that the importance of tourism to A&B's economy is physically reflected in its high share of nearly 20% of the country's material stocks and brings to the forefront several otherwise obscured resource e fficiency challenges. With visitors comprising 8–11 times the population of A&B, huge volumes of material stocks are needed to support the industry but are only in use for a few months of the year during the tourism season. This under-usage of buildings, infrastructure, and materials is perhaps not a serious issue for the bottom line of the tourism industry and developers. However, it stands as a resource utilization ine fficiency and therefore perhaps represents a market failure from the sustainability perspective, similar to the case of idle vehicles recognized elsewhere [74].

Beyond the expansion of the stock, a second demand for inflows is for the maintenance, replacement, and operation of the already existing stock. As material stocks accumulate and eventually reach their end of life, this second type of demand increases [75], and even in economies with relatively steady levels of stock, substantial inflows are still required for these ends [76]. The extension of the useful life of buildings and infrastructure can lower the scales of these maintenance and replacement demands and concurrently also demolition outflows. However, in A&B's recent history and perhaps its future, a substantial portion of the stock requires constant replacement not because of reaching its end of life but because of disasters, which means constant reliance on imports just to maintain current stock levels. This is extremely environmentally and economically unsustainable and requires measures involving integrated policy, planning, and construction of more resilient buildings and infrastructure to avoid these throughputs of materials. For any remaining unavoidable outflows, local technical and institutional capacities to reuse materials are required. Our results can directly inform the formulation of such policy.

#### *7.2. The Influence of Tourism Material Stocks on the Growth of Island Services*

At the same time, a spatial analysis of the distribution of material stocks in A&B highlights the hotspots of the location of the built environment and their associated services. The concentration is in areas of increased commercial centers and tourism-based services, where most physical infrastructure development also takes place. The main hotspots are close to the island's coastal areas. The capital, St. John's, shows a high material stock accumulation within its core, and this location also hosts one of the island's central business hubs, in addition to accommodating the passage of all the cruise ships docking on the island and the main seaport. The high accumulation of material stocks with St. John's city (Figure 4) can be connected to the many services that are provided by the built environment within the city core, thus building upon the material stock–flow–service nexus, a feedback loop recently explored by Pott et al. [31] (paper submitted) in Grenada.

The outskirts of the city core are surrounded by a growing urban residential area where a smaller quantity of MSs can be found. Residential development has favored the northern side of the island where pockets of medium–high material stocks are distributed, as well as where the airport is situated. MS is present with low–medium levels in the middle of the island where primary and secondary roads are used to travel to the southern end of the island. This type of development is referred to as ribbon development and, according to Davies (as cited in Cohen, [77]), (p. 226), ribbon developments are "beaded clusters of activities strung out alongside major roads ... that may contain a high incidence of services and sometimes a mixture of small wholesale and manufacturing establishments". Figure 4 also illustrates secondary hotspots on the island which coincide with major tourist hubs including Jolly Harbour and English Harbour. Both tourism hotspots are identified as "intensive tourism activity areas" and the developmental pattern is reinforced for areas that are already economically successful in A&B [52]. Such a model of development stimulates additional services (outside the focus of hotels and restaurants) which can be easily accessible to visitors such as non-resident villas, marinas, car rentals, shopping centers, and banking facilities.

#### *7.3. The Importance of Building Resilience*

The spatial distribution of material stocks and services raises concerns about the levels of vulnerability the tourism industry faces with climate change. As illustrated by Figure 4, the concentration of material stocks for tourism is primarily located along coastal areas. Beachfront properties are ideal locations for access to beaches, resorts, and other tourist accommodations. As a result of this concentration of development on the coast, SLR and extreme climatic events can result in abruptions and disturbances within the tourism sector [78]. Tourism is identified as the most vulnerable building use type exposed under a 2 m sea rise scenario. The study takes a conservative approach on the SLR vulnerability assessment, based on estimates of the global SLR by 2100, with the highest scenarios measured at 2 m. Emerging studies show estimates of global SLR ranging below 2 m [79] and after a revision of the NOAA SLR scenarios in 2017, the worst-case scenario increased by 0.5 m, with the current estimates measured at 2.5 m by 2100 [80]. While estimates continue to change with ongoing research and evidence, the key message in this paper does not change: SIDSs are faced with major threats to their infrastructure with a 2 m SLR [26,30,81]. In fact, under a 1 m sea level rise scenario, 29% of the major resorts in the Caribbean would be partially or fully inundated [82]. Moreover, the economic evaluation conducted by Moore et al. [83] of various climate change scenarios for Caribbean destinations estimated a projected loss of USD 118–156 million in tourist expenditure by 2100 as a result of projected climatic shifts.

In addition to SLR, hurricanes and the higher frequency of strong weather systems is another area of concern [84]. A&B has experienced severe category 5 hurricanes in the past, causing widespread damage. The 2017 category 5 hurricane Irma resulted in significant destruction of Barbuda, both by being in the direct path of the storm, as well as by virtue of its low elevation of 3 m above sea level [85]. The aftermath left behind high volumes of debris from the dysfunctional infrastructure, which accounted for 90% of the total buildings in Barbuda, resulting in the loss of essential services

such as transport, health, and education. Between 1851 and 2017, A&B has experienced 128 storms and hurricanes, and the financial cost due to this has been USD 950 million in the past 12 years alone [85,86].

Tourism is both weather dependent and reliant on natural ecosystem services (beaches, coral reefs, waterfalls, etc.), and impacted by climate change [78,87,88]. In fact, tourism is one of the most climate-sensitive sectors globally, impacted by all 10 types of climate change impacts (such as floods, droughts, warming, heatwaves, precipitation, and sea level rise) [89]. Moreover, the development of tourism itself threatens the fragile ecosystem on which it depends. In A&B, for example, the YIDA International development project gained the public's immediate attention when over 2000 acres of coastal land, one of the largest marine protected areas (MPAs), were sold to establish an "economic zone". This area included mangroves and nesting grounds for endangered and threatened species. The loss of 75% of mangroves resulted in a loss of local livelihoods depending on these resources, but also increased exposure to the impact of hurricanes and flooding [88,90], creating a negative feedback loop for the economy. At the same time, tourism relies on the international transport industry and the high level of interconnectivity by air or sea to global markets. In A&B, the majority of the visiting tourist population originates from the US, Canada, and Europe [91]. In 2017, tourists from the USA accounted for 39% of total air arrivals, Europe 37%, and Canada 9%. Therefore, for the island's tourism sector to be operational, the country depends on international airlines and the cruise industry. However, in situations where the country is in shutdown and transport is suspended due to a natural disaster or a worldwide pandemic (such as COVID-19), the sector comes to a standstill. Besides the loss of jobs, large portions of the built infrastructure for tourism will remain further underutilized. Transport infrastructure located on the coast is highly threatened by the e ffects of climate vulnerability and change [81], as observed in A&B. Table 2 illustrates that in an under 2 m SLR scenario, approximately 14% of transportation material stocks would be exposed, including airports and seaports.

Thus, small island states like A&B, where tourism is a high contributor to the GDP, are among the most vulnerable nations, with climate change posing significant barriers to tourism's contribution to the Sustainable Development Goals (SDGs) [5]. In 2014, the UN World Tourism Organization [92] outlined core challenges facing the survival of the tourism industry, from climate change to the need to conserve the stressed and fragile local ecosystems, to the drain on foreign exchange of recurring imports of construction material. The Caribbean Group for Cooperation in Economic Development [93] explains that natural disasters are inherently a developmental issue, as there is evidence of unsustainable planning and investment decisions in the aftermath that contributes to vulnerability. Although tourism is the main economic driver in A&B, it is also the most vulnerable and volatile industry. All of this questions the sustainability of material stock accumulation within A&B's tourism sector, and the urgen<sup>t</sup> need for economic diversification.

#### **8. Conclusions and Outlook**

Socio-metabolic research on small islands in the context of sustainability is still an emerging field, and the body of literature surrounding this field is only now beginning to show. As reviewed in Section 3, most socio-metabolic studies so far have been "flow" focused, and very few on "material stocks". This paper is a novel contribution to our understanding of societal services (tourism in this case) from the perspective of material stocks and flows (referred to as the "material stock–flow–service nexus"). A socio-metabolic perspective on tourism can o ffer relevant information to policymakers to identify opportunities to decouple the tourism sector from resource requirements and build system resilience [1].

In a single-driven service based-economy like A&B and other Caribbean countries, the material stock–flow–service nexus is an instrumental approach in understanding local-scale resource flows, material stock growth, and determining resource requirements for achieving the Sustainable Development Goals (SDGs), in particular SDG 12 (responsible consumption and production) and 13 (climate action). The material stock–flow–service nexus approach has the potential to o ffer insights to

better understand island economies and their overall sustainability. By focusing on the interrelationship between stocks, flows, and service, policymakers can identify those services that are driving biophysical growth, who benefits from them, and to accordingly foster inclusive sustainable development. It is argued that tourism can also create spatial disparities in terms of social and economic development, where an island's spatial distribution impacts the island's societal development which can di ffer amongs<sup>t</sup> islands [94–96]. For example, decisions that restrict access of local residents to beaches located within tourism hotspots or the amount of land made available for tourism expansion versus the amount of land catered towards societal development. In addition to the volume of infrastructure attributed to tourists compared to local residents, tourist-centered areas can become "islands within islands" that restrict the use and access to services by residents from the surrounding communities. Local development projects must take into consideration these concerns before future tourism-related construction takes place on the island. The governmen<sup>t</sup> and policymakers will need to create greater inclusivity and sustainable growth within the sector [97], asking whether the costs and benefits of building stocks and related services are equally distributed across society. In other words, sustainable infrastructure development and the allocation of material stocks should consider the resident population and their social and economic wellbeing (SDG 13—sustainable communities) [98].

There is no doubt that SIDSs are threatened by a heightened risk from climate change. Increasing disaster preparedness and to protect the socio-economic services delivered by the tourism sector, the combined use of geospatial analysis, material stock–flow–service accounting approaches, and scenario exercises can assist island governments and businesses in improved planning and dealing with uncertainties [99]. SIDSs will benefit from further research incorporating new data sets with the study's methodology to expand on the sea level rise and climate vulnerability analysis. Sustainable tourism must include several core principles such as economic viability, physical integrity, community wellbeing, and resource e fficiency [78]. A holistic and inclusive approach is likely to enhance tourism's ability to contribute to the SDGs and, to some degree, shield it from the negative impacts of climate change. However, factors such as geographic location and the country's ability to build adaptive capacities to cope with expected changes will also be key in increasing the sector's resiliency.

**Supplementary Materials:** The Supplementary Information provides greater detail on the methodology section of the research including the material stock analysis (MSA) of buildings, building footprint classification, empirical evaluation and data collection, building use type classes and height assumption, material intensity typology, and residential material intensity: Monte Carlo simulation. Available online: http://www.mdpi.com/ 2071-1050/12/19/8090/s1.

**Author Contributions:** Conceptualization, J.B., S.J.S., S.-Y.T., and T.F.; methodology, J.B., S.-Y.T., K.P., and T.F.; validation, J.B., S.J.S., S.-Y.T., and T.F; writing—original draft preparation, J.B. and S.J.S.; writing—review and editing, J.B., S.J.S., S.-Y.T., and T.F.; visualization, J.B. and S.-Y.T.; supervision, S.J.S., S.-Y.T., and T.F. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Conflicts of Interest:** The authors declare no conflict of interest.
