Research Perspectives on Buildings’ Sustainability after COVID-19: Literature Review and Analysis of Changes

Abstract

The concept of sustainability introduced in 1987 has characterised the world of research in the AEC (Architecture, Engineering, and Construction) sector, directing it to try to tackle the problems inherent to the impacts of climate change on buildings. In addition, the advent of COVID-19, disrupting the world and people’s habits, has obviously also strongly affected the academic world. Indeed, this paper aims to analyse the changes and differences between the pre- and post-pandemic periods through a two-stage hybrid literature review. First, through a systematic literature review, 90 articles were selected, filtered through different keywords (sustainability, climate, architecture, and buildings). Once the reasoned selection of papers had been made, it was possible to proceed to the second phase, which involved a thematic analysis according to the three classic macro themes of sustainability (Environment, Social, and Economic) and the inclusion of a fourth macro theme (Management and Development), which made it possible to reintroduce a holistic view of the problem. The results of this literature review revealed the presence of a growing interest in the topic analysed and a more homogenous distribution across all continents, with no distinction between developed and developing countries. Economic sustainability interests emerge post-COVID-19 through the deepening of the themes of clean energy and direct control of consumption. At the level of Environmental sustainability, on the other hand, COVID-19 replaced the house at the centre of people’s lives. In addition, the Management and Development macro theme highlighted the need for an integrated view of the problem and the unexpected return of researchers preferring new constructions, which, despite alternative green approaches and renovations, can guarantee better performance.

1. Introduction

The topic of environmental sustainability and the effects of climate change are growing rapidly in every sector and represent a global interest.

Non-scientists and people without a technical scientific background have also started to become aware of this through the considerable efforts of activities and programmes not strictly related to academia. The activities proposed, for example, by the young Swedish activist Greta Thunberg in favour of sustainable development and against climate change, as analysed by researchers at the Swedish University of Gävle, embodying the typical characteristics of the “moral leader”, seek to direct people towards the prevention of climate change through the dissemination and promotion of more sustainable solutions aimed at environmental protection [1]. At the school and student levels, the strikes promoted in favour of climate action launched by G. Thunberg in 2018 contributed to many students asking the question “What is the point of education if we have no future?” and then coming together in the international student movement Fridays for Future. Some Australian schoolchildren in the city of Brisbane, stimulated through research and programmes in which they were personally involved, have come to the conclusion, even at a very young age, that better education with a focus on sustainable environmental management is the winning strategy for having a future [2].

Therefore, keeping in mind what is happening outside the academic world helps with better understanding how the topics of sustainability and climate change in the last five years are no longer the prerogative of commissions and institutional bodies. On the contrary, perhaps due to a growing lack of trust in political institutions, the world of education, and more specifically teachers, is being asked to take on the task of educating professionals and non-professionals alike on the most effective strategies to best address sustainable development and the impacts of climate change.

Indeed, the university academic world has contributed and continues to contribute through specific research programmes. In the European context, for instance, the Finnish University of Tampere, together with the Alma Mater Studiorum—University of Bologna in Italy, the TalTech of Tallinn in Estonia, the Irish University of Dublin, and the University of Aarhus in Denmark, coordinated the Erasmus Plus Programme, called Arch4Change, with the aim of studying and analysing existing methods and tools and proposing new pedagogical approaches based on innovative digital tools to support and improve the knowledge and skills of AEC students and teachers regarding environmental and climate sustainability in Design [3].

Research usually aims to try, albeit through very small steps, to change the world and the lives of the people in it for the better. Having been able to take part in the aforementioned Erasmus Plus project and having had to live with the pandemic events that have completely turned the world upside down in the last 3–4 years have given rise to inverted reasoning with respect to the classic point of view of research. The underlying thread of this reasoning is aimed at trying to understand if, how, and to what extent the tragic event that began in the first months of 2020 may have changed the way in which researchers in the fields of architecture and construction perceive and deal with issues related to sustainability and the impact of climate change on buildings.

To develop this research, we started with the analysis of data related to the construction sector, which is one of the main causes of the climate crisis in Europe, contributing 36% of the carbon dioxide emitted annually due to it making up 40% of the annual energy consumption [4]. Hence, the aforementioned events and opportunities led us to inquire, “In what manner has the research perspective on sustainability issues and the impact of climate change on buildings changed in light of the COVID-19 pandemic?”. This query subsequently became the final goal of this survey.

2. Literature Review

2.1. Introduction to Sustainability and Sustainable Development

The concept of sustainability, or sustainable development, was introduced in 1987 through the UN Brundtland Report, in which it is defined as “a development that meets the needs of the present without compromising the ability of future generations to meet their own needs” [5].

The strong and proper impetus included in the aforementioned report to protect countries in crisis or developing countries has not, however, distracted the attention of the Urban Crisis Commission from what was and is happening in the cities of the industrial world, given that these “represent a high share of global resource use, energy consumption, and environmental pollution”. Indeed, due to their behaviour and needs, many of these cities have an impact that goes beyond their urban boundaries by sourcing “resources and energy from distant territories, with enormous overall impacts on the ecosystems of these lands” [5].

2.2. The Construction Industry and Approaches to Sustainability in the Global Context

The construction industry is a complex and articulated machine and, at the same time, decisive for the world economy (and, consequently, for each individual nation). For a clearer reading of these statements, let us look at the data on the volume of business sustained in 2021, the year of recovery after the advent of the SARS-CoV-2 virus. The market value of the construction industry in that year was valued at USD 7.8 trillion, and with a production expenditure volume of USD 13.2 trillion and more than 180 million workers employed worldwide, it recorded revenues of more than USD 12 trillion. According to industry experts, these numbers are expected to increase in the coming years, and it is predicted that in 2030, with an expenditure volume of USD 14.4 trillion, revenues will exceed USD 22 trillion [6,7,8]. In Italy alone, driven by the tax incentives proposed by the state, such as Bonus 110, the construction sector grew by 27% in 2022 [9].

In order to tackle the issue of sustainability—a concept that is in itself far too vast, even if restricted to the field of construction—over the years, an attempt has been made to simplify it by breaking down the problem into several variables or areas of intervention. For this reason, although the ultimate aim is always to reduce the impact generated by the construction sector, in specific terms, it has started to refer to three different types of interconnected sustainability: environmental, social, and economic–financial. The CEN (European Committee for Standardisation) has also tried over the years to make its own contribution by supporting the various professionals involved in the AEC sector by dictating the rules of this new way of perceiving architecture. For example, the latest updates of the standards UNI EN ISO 14008—Monetary assessment of environmental impacts and related environmental aspects and UNI EN ISO 14006—Environmental management systems—Guidelines for the integration of ecodesign date back to 2019 and 2020, respectively [10,11].

2.3. The Intersection between Sustainability, Climate Change, and COVID-19

The concept of sustainability is closely linked to climate change issues, and for this reason, in 2022, the European Commission “committed to supporting the integration of climate resilience considerations into the construction and renovation of buildings”, by commissioning the Danish consultancy Ramboll and the CE Deft, a Dutch research and consultancy centre, to undertake “a study to collect and synthesise existing methods, specifications, best practices, and guidelines for climate resilient buildings” with the final aim of drafting guidelines entitled EU-level technical guidance on adapting buildings to climate change [12].

One of the main goals of these guidelines will be to mitigate the priority risks that may affect buildings due to climate change so as to achieve an in-depth review of vulnerability and climate risk assessment methodologies (see Figure 1, RAMBOLL infographic).

This research examines a multitude of documents of various types and provenance from recent studies undertaken by the European Union and academic studies, until the regulatory instruments that guide the building sector in each individual country, “will consider any variation required for different scales of buildings, from the individual to the whole block, providing feedback on the impact, ease of use, and synergies/conflicts of the methodologies” [12].

2.4. COVID-19 Implications of Environmental and Economic Sustainability

In the field of environmental sustainability, with regard to the problem of climate change, research has already been trying to make its contribution for several years, but three years ago the world was shaken by a totally unexpected event, the COVID-19 pandemic.

This worldwide pandemic upset and transformed, in the space of just a few months, the way people behaved and the way they perceived the world around them, drastically altering their perception of the spaces and environments in which they daily lived, worked, or simply spent their free time [13].

The link between the advent of COVID-19 and sustainability consists of a multiplicity of psycho-sociological and perceptual aspects, such as the fact that the occupancy pattern of buildings turns out to be one of the determining factors in assessing the energy performance and sustainability of buildings [14].

During the pandemic, due to the lockdown, there was an almost complete emptying out of offices, resulting in an improvement in the sustainability rating of the buildings that housed them and a profound decrease in transport pollution, both public and private, at the disadvantage of a consequent worsening of the sustainability rating of individual buildings in the residential sector.

As shown in Figure 2, in fact, considering that the minimum cubature of a classic office room, e.g., that of a public administration, must be at least 10 cu. m. per employee, multiplying by the number of employees present (4) and dividing by the mandatory minimum height (2.7 m for residential), we obtain approximately 15 sq. m. per employee. This size turns out to be the same as required for the living room (minimum 14 sq. m.) of a residential building [15,16]. Assuming for approximation that both rooms (office and living room) have a similar number of radiant elements, it can be assumed that during the periods spent working at home, the energy consumption required to heat the classic office room is no longer shared by the four colleagues but must be multiplied by four, i.e., to heat each individual room, in this case the living room, in which each employee worked. (NB: this is of course only an example estimate, but it is intended to quickly show the effects of the lockdown and the impact on individual homes.)

Professionals and workers were not the only ones who had to quickly change their work habits, transforming their homes into private offices from which to interact by video call with colleagues. In many of those home offices, students also had to coexist and find their own space while busy trying to attend classes, study, and interact with their peers through online classes and courses. On the level of social sustainability, it should be noted that some students, for example, those engaged in the transition from middle school to high school or from high school to university, found themselves interacting for at least a year with colleagues they had never met except in virtual spaces. The future will allow us to understand how much such an event may have affected young minds in the midst of physical, intellectual, and hormonal development and what kind of social side effects it may have caused [17,18].

2.5. Renovations and Energy Efficiency Improvements in the Construction Sector

Once the lockdown period had passed, the slow return to normal occupation of workplaces began, which at the same time had often been subjected to a complete redesign of spaces and a strict separation of internal pathways.

Certainly, if compared regarding the concept of sustainability, the impacts resulting from climate change and that due to COVID-19 appear to be travelling on parallel tracks but at completely different speeds. Compared to the disruptions caused by the pandemic, the impact attributable to climate change appears to have effects on buildings and their users that can be observed more in the long term. In both cases, however, the more or less significant consequences of these impacts will lead to non-negligible changes in the behaviour and perception of re-occupied spaces [19,20].

Taking climate emergencies into account during the design phases becomes a fundamental aspect of the new way of conceiving sustainable architecture, and professionals must be an active part of this radical change in perspective. Driven by these motivations, a number of researchers initiated a project to direct students towards these issues even before they became professionals. By working on teaching methods and students, in fact, it is possible to ensure that they, through their academic careers, acquire the appropriate tools to implement the changes in perspective that the AEC sector needs in order to pursue better sustainable architecture [21].

In the construction sector, the desire or need to converge efforts as much as possible to achieve ever greater levels of sustainability is also dictated by purely economic and practical aspects.

In recent years, both in the Italian and international contexts, the desire to pursue the economic and environmental sustainability of buildings has encouraged the preservation of the existing heritage with respect to possible demolition, reconstruction, or new construction. Renovations aimed at preserving the aforementioned building heritage have the main objective of improving the building’s performance in various aspects, mainly energy.

In Italy, for example, considering only the hospital sector, 85% of healthcare facilities were built before the early 1900s, with the consequent result that 80% of operating theatres today are non-standard in terms of minimum suitability requirements [22].

The data for the residential sector are no longer comforting. The Italian government, with the aim of restarting the economy and overcoming the problems that had emerged due to the coronavirus, by exploiting the flywheel of sustainability, proposed significant tax breaks for renovation work in the residential building sector with the purpose of improving energy efficiency. In order to obtain these reductions, renovations had to aim for a mandatory improvement of two energy classes of the building compared to the situation at the beginning of the work.

According to the report of the Italian National Agency for New Technologies, Energy, and Sustainable Economic Development (ENEA), as of September 30, 2021, the number of renovations attributable to the Bonus 110 tax break exceeded 46,000 properties, for a total of EUR 7.5 billion in investments [23].

Concerning the issues related to the sustainability of the existing building heritage, in 2013 researchers from numerous European universities and research institutions, thanks to the European Union’s Intelligent Energy Europe programme (IEE), began to be concerned and deal with “making transparent and effective energy refurbishment processes in the European housing sector”, first through the cataloguing of building types present in Europe (Project TABULA), which then extended to the “development of building stock models to assess renovation processes and predict future energy consumption”, leading to the drafting of an “agreed set of energy performance indicators that will allow key actors and stakeholders to ensure, at different levels, a high quality of energy renovations, compliance with regulations, to monitor and guide renovation processes in a cost-effective way and to assess the energy savings actually achieved”, the ultimate goal of the EPISCOPE project [24].

2.6. COVID-19 and Its Impact on the Global Supply Chain

Environmental sustainability and economic sustainability, although they both serve the same purpose, due to the different domains in which they operate, may find themselves making choices in opposition to each other. A glaring example, which emerged during the pandemic and has largely persisted up to the present day, is the negative impact of COVID-19 on the global supply chain. This problem has an even more serious impact when materials produced in one country are denied the shortest route to their destination site. This interruption makes it impossible to implement a sustainable supply chain, the ultimate aim of which is to try to reduce greenhouse gas emission levels by designing the fastest link between supply and demand. A link was, indeed, impossible to make during a pandemic with entire nations in lockdown [25].

Moreover, global supply problems are exceedingly difficult to address, not only for highly developed nations but especially for small developing states. Within this category, for example, the Small Island Developing States (SIDS), basing their economy purely on the tourism sector (e.g., the Seychelles’ GDP is 67% due to tourism), in addition to suffering from the negative impacts of climate change for years, have suffered dramatic drops in their GDP due to COVID-19, on average 7.3%, with peaks of 16% for the Maldives and Seychelles. Furthermore, the obligation to deal with disasters caused by the increasingly frequent occurrence of extreme weather events has deeply undermined their already fragile economy, hampering their ability to deal with further natural disasters. In the same year as COVID-19, for example, the pandemic and quarantine prevented SIDS from providing the necessary health and humanitarian assistance after Cyclone Harold struck.

The scientific community, through the International Science Council (ISC), set up a scientific committee to support these small states as early as 2020, while the Organisation for Economic Co-operation and Development (OECP) has initiated studies to map the disastrous consequences on the economies of these states due to the advent of COVID-19. According to the UN, SIDS face substantial challenges in terms of sustainable development from the pandemic, climate change, and the political choices of the rest of the world and therefore require urgent support—financial, technical, and material—from the entire international community, scientific and otherwise [26,27,28].

In light of the analysis of the main issues related to sustainability in the building sector, the main objective of this research is to understand, through a review of the literature inherent to the topic, how the way of perceiving sustainability and the impact of climate change on buildings have changed since the advent of COVID-19.

3. Methodology

The main purpose of this investigation is to try to analyse and understand how much a dramatic and shocking event such as the advent of COVID-19 in everyday life may have contributed to changing the perception in academia of both the concept of sustainability and the importance of the impact of climate change in the construction sector.

In order to better structure the search for useful data and be able to start answering our main question, we decided to follow a four-step survey methodology, each one useful to direct the next step to be taken and respond to a precise query (see Figure 3).

Once we had defined the starting point, namely the reason for this literature review, the next step was to define where to look for our answers. In this case, in the first instance, the idea was to work directly on several databases at once and weave the data between them. Specifically, the choice was initially oriented towards two Elsevier databases, Scopus and Engineering Structure, and one ASCE.

This approach, although later abandoned, was useful to test through 30 articles the type and feasibility of the analyses that would later be conducted; it practically assumed the function of the prototype of the review itself. The motivation that initially led us to abandon this way of working in favour of the use of a single database, in this case Elsevier’s Scopus, was not only the practicality of managing data from a single source, but above all the fact that we could deal with comparable data without having to invent correspondence systems due to the different treatments that each database reserves for its own data, such as the keywords for indexing the article, the evaluation or citation system, or having to take into consideration the differences in the dissemination of the database itself.

Once we had defined the knowledge database to refer to and draw data from, we tried to define the amount of data at our disposal by using the two main keywords, sustainability (165,018 articles available since 1982) and climate change (301,788 articles available since 1901), and defining a time range. For the keyword climate change, in order to avoid losing any other associations, e.g., with impacts, problems, etc., we preferred to take into consideration the larger dataset related to the word climate alone (498,868 articles available since 1907).

Although the definition of sustainability dates back to the late 1980s [5], the keystone event of our analysis comes from 2020, and examining 40 years of research might have been counterproductive without the introduction of a careful analysis of all the other world events that have brought about more or less important stances and/or upheavals on the issue of sustainability and climate change. For this reason, taking into consideration only the data obtained from the intersection of the datasets relating to both keywords, we preferred from the outset to move the extreme left-hand side of the time span directly from 1988 to 2007, the year in which at least 100 articles began to be published annually. On the other hand, the right extreme, having little wiggle room, only suffered the 2023 cut-off, which cannot be considered a stable source of data because it is still in progress and undergoing daily changes and updates. Finally, with the last modification of the left extreme from 2007 to 2008, a time span of 15 years was defined, from 2008 to 2022, with a total database of 11747 searchable articles.

To further circumscribe the data in our possession, we introduced two additional keywords: architecture (365,255 articles, 2008–2022) and building (337,416 articles, 2008–2022). This, in addition to limiting the number of articles, allowed the available data to become more relevant to the AEC sector in which we operate.

In contrast to what was carried out before with the datasets from the words sustainability and climate, in this case the data from the four keywords were not intersected all together, as this could have led to the exclusion of many interesting data, but instead it was preferred to operate with two distinct clusters through the intersection of three datasets at a time, as illustrated in Figure 4.

This operation allowed us to arrive at under 1000 available data, namely 798 articles, obtained from the union of two collections of data: the first of 124 articles, obtained from the intersection of the sets referring to the three keywords sustainability–climate–architecture, and the second of 674 articles, obtained from the intersection of sustainability–climate–building.

Two lists were extrapolated from these two collections, taking for each of them 5%, in excess, of the articles published each year. The first, referred to as List A, consists of 13 articles, while List B consists of 36, for a total sample of 49 articles published from 2008 to 2022.

For the creation of both lists, articles were chosen by considering those that had obtained the highest number of citations by January 2023, skimming off any articles that, for indexing reasons, were in the set but were distant from the main research topic.

Although the final database defined by 49 articles allowed the various analyses useful for answering the questions that gave rise to this survey to be conducted, the idea of being able to conduct an even more accurate analysis through the use of multiple databases still seemed to be the best strategy. In order to implement it, however, we decided not to repeat the process just described on the other databases hypothesised at the beginning, but, due to the subject of the survey, we considered it more correct to focus on the analysis of a database characterised by articles strongly linked to the theme of sustainability. For this reason, MDPI’s Sustainability journal database was chosen.

For this database, all the same steps described for the Scopus database were conducted.

Firstly, we again circumscribed the amount of data present through the keywords sustainability (1,021,319 articles available from 2002 to 2022) and climate (40,603 articles available from 2005 to 2022). Further, by interweaving the data from these two sets and using the same time range defined for the Scopus database analysis (2008–2022), we obtained a total database of 953 searchable articles.

The subsequent level of skimming involved, again, the introduction of the two keywords architecture (2903 articles, 2008–2022) and building (6652 articles, 2008–2022).

Even with this database, the intersection of the datasets obtained by means of keyword triples allowed us to stay under 1000 data available. In detail, the 956 data obtained are divided into two clusters: one of 139 articles obtained from the sustainability–climate–architecture keywords and one of 818 articles from the sustainability–climate–building keywords.

Finally, to define the two lists A and B of the MDPI database, we noted that we could further narrow the range to 2013–2022 due to the few papers present in the five-year period 2008–2013.

Thus, by taking from each collection 5% in excess of the articles published each year—and by default, at least one article in the rare cases where this percentage was unable to meet the requirement—we obtained List A of 13 articles and List B of 31.

Also in this case, the articles were chosen by taking into consideration those that had obtained the highest number of citations, discarding any articles that, for indexing reasons, were in the set but were distant from the main theme of the search.

Having reached this point and having obtained comparable datasets from each database, we merged both the A and B lists, resulting in a total of 93 papers. The merging of lists A and B of the two databases revealed that three articles selected in the MDPI database had already been selected through the first systematic review. For this reason, we obviously eliminated them, resulting in a total of 90 unique articles (see Figure 5 and Figure 6).

Figure 6 shows the flowchart of the entire literature review process, from the initial question (START), which started the survey, to the collection of data and their analysis, as described in this chapter, and finally to the final results and conclusion (END), which will be shown in the following chapters.

4. Results and Discussion

The main objective of this review is to attempt to highlight, through the management and analysis of the 90 papers extracted from Elsevier’s Scopus database and MDPI’s Sustainability database according to the procedures described in the previous paragraph, any changes in perception (that can be recorded) within the world of research regarding the concepts of sustainability and the impact of climate change on buildings after the advent of COVID-19.

After conducting a systematic analysis of the literature, we decided to investigate through a thematic analysis of the papers, which, starting from the analysis of their distribution and annual publication trend, arrives at a comparative analysis according to four macro themes (see Figure 7). In addition to the three classic macro themes of sustainability (Environmental, Social, and Economic), we have in fact added a new macro theme—Management and Development—which focuses more on the aspects of planning/management and sustainable development with an integrated long-term vision.

The papers involved authors from universities and research institutions from 47 different countries distributed over five continents (only Antarctica remains excluded). As can be seen from the pie charts, prior to COVID-19 (Figure 8A), the data analysed show an interest expressed more by academics from European universities (50.8%) and the presence of articles from only four continents (Europe, the Americas, Asia, and Oceania). From 2020, on the other hand, we can see that interest is more evenly distributed across all continents, with academics from countries on the African continent also participating (see Figure 8B). The greatest growth can be seen among papers from the Asian continent—from 22.3% to 37.6%—partly attributable to the media exposure of the Chinese city of Wuhan as the epicentre of the epidemic.

This difference in distribution can also be seen in the bar graphs (Figure 9), where before COVID-19, a more punctual distribution could be seen. The greatest interest in sustainability topics is concentrated on a few nations (green bars pointing downwards), among which the United Kingdom stands out especially, followed by Australia, Spain, Saudi Arabia, and Canada, while post-COVID-19 the interest in the same topics is less confined to a few nations in favour of a wider distribution (red bars pointing upwards), with a growing interest of academics from Asian (from 22.3% to 37.6%) and African (from 0% to 5.3%) nations. These data testify to the scientific community’s commitment to tackling major global challenges, irrespective of which university they come from, whether from a highly developed nation or a small developing state.

The graph in Figure 10, on the other hand, based on the data obtained by rounding up the 5% of annual publications selected for this research, shows the growing interest in the topics/issues of sustainability and climate change, highlighting how the advent of the pandemic has led to a decisive increase in publications. According to the extrapolated data, almost as many papers were published in the three-year period 2020–2022 as in the entire previous decade.

The second type of analysis, on the other hand, involves keywords, titles, and abstracts.

Taking into consideration the keywords chosen by the authors at the time of publication of their paper, an attempt was made to identify the main themes and issues dealt with within the various papers, subdividing them by pre- and post-COVID-19.

In order to bring out more clearly the themes with which the concepts of sustainability and climate change were dealt with during the 15 years examined, the extrapolation algorithm was set up so as to group similar words, e.g., develop and development, or words with overlapping meanings, e.g., avoid considering assessment and evaluation as two separate words, so as to avoid miscounting. Furthermore, since it did not make sense to bring them up in this context, the keywords (architecture, architectural, building, buildings, climate change, sustainability, sustainable) previously used to obtain the 94 articles under examination from the Elsevier and MDPI databases were excluded in the algorithm settings.

After the counting, we proceeded to subdivide the keywords according to four macro themes: the three classic areas of sustainability—Environmental, Economic, and Social—to which we added a fourth area, defined as Management and Development. This subdivision not only brings the analyses in line with the main theme of this survey but also makes it possible to conduct a targeted comparative analysis.

The comparative analysis of the Environmental macro theme (see Figure 11) highlights the constancy and importance of the Energy theme, which continues to be a central pillar of the environmental debate, regardless of external circumstances. In addition, it can be seen that before COVID-19, interest was more focused on technical–scientific aspects (efficiency, performance, humid, bioclimatic), with an interest in the entire life cycle of the building (life cycle), while after the epidemic, the topics most discussed were those concerning clean and renewable energy (zero, emission, renewable, green).

The second comparative analysis concerns the Economic macro theme (see Figure 12). Through this analysis, we can see how the importance that in the past was given to analyses and evaluations (assessment, analysis), which we could say were linked to the technical–scientific aspects we spoke of in the previous comparative analysis, from 2020 passes into the background, joined by purely economic interests (demand, economy) but, above all, replaced by interest, or perhaps more so by concern, for the theme regarding energy consumption (consumption). Thus, a transition can be noted from approaches linked to detailed studies and analyses towards the search for immediate answers triggered by compelling needs and necessities, daughters of the advent of COVID-19.

The third macro theme covered by this comparative analysis is the Social one (see Figure 13). In this case, the importance of design remains constant, as does interest in the urban aspect and the heritage it contains (design, urban, heritage). However, we can see how, post-COVID-19, there is a marked increase in interest in the home and the environments that make it up (residential, comfort). This can be attributed to the forced rediscovery of the home as the fulcrum of everyday life, due to the months of isolation. Place(s) that allowed us to live and work even if not expressly designed to meet these new extraordinary needs became important. The resilience of a building (resilience), a characteristic studied and, above all, researched in the pre-pandemic period, is completely neglected, probably also in this case to meet extraordinary demands that needed immediate design responses/solutions. This comparative analysis, although focused on the comfort of the building—both in terms of the spaces it is made up of and in its urban reality—highlights the importance of trying to think more and more globally and how it is no longer possible and convenient to limit ourselves to the management of our own back yard (world).

The last comparative analysis focuses on the keywords that have been collected under the macro theme of Management and Development (see Figure 14).

In this comparison between the data referring to papers published before the advent of COVID-19 and those from 2020 to 2022, we can easily observe how, with the exception of construction materials (materials), which remain a constant topic of interest over time, there has been a net change in interest. The various green building approaches that, until 2020, were considered among the best strategies to address the sustainability of a building or the climatic impacts to which it could be exposed are totally sidelined (biomimetic, facade, passive, wood, roof, vernacular). After the advent of COVID-19, there seems to be no more time to look for alternative forms of sustainable architecture; on the contrary, there is more of a demand for concreteness and development that directs projects towards a high-performance future (smart, development, planning).

Moreover, with the health emergency, one of the architectural industry’s certainties of the past years has come undone (refurbishments, conservation, adaptive). For almost two decades, in fact, the idea was supported that renovating and refurbishing existing buildings was the best solution to make the AEC sector more sustainable due to less CO₂ production. However, the needs arising from the pandemic have shown that lower CO₂ production also corresponds to a limitation of the performance achievable through renovation. Instead, the performance required to satisfy the post-pandemic demands would only be achievable through a renovation so far-reaching that it could be compared to a new construction. New construction, although a cause of heavy pollution, allows greater freedom of action and total fulfilment of requirements in a dramatic situation such as the pandemic.

The emergence of these three themes (smart, development, planning) in the post-COVID-19 period, moreover, underlines the importance and necessity of the introduction of this fourth macro theme, a different point of view from which to analyse sustainability. In fact, the classic subdivision into the three macro themes—Environmental, Social, and Economic—makes it possible to address the three P’s (people, planet, and profit) but at the same time neglects certain interconnections and interdisciplinary challenges present upstream of the aforementioned three macro themes, addressing their issues without a complete integrated long-term vision, which can instead be reintroduced through the fourth P of planning, characteristic of the Management and Development macro theme.

What emerged from the comparative analyses of the keywords was also examined in the titles and abstracts. Naturally, more emphasis was placed on keywords precisely because of their non-discursive characteristic, which makes it possible to summarise the topics in extreme synthesis. Titles and abstracts, on the other hand, due to their discursive characteristics, are more suitable for confirming trends, possibly bringing out some eccentricities. For this reason, the comparative analysis conducted on them did not envisage the subdivision of the words into macro themes but the highlighting of the trends in order to compare them with those that emerged from the comparative analysis of the keywords.

As can be seen in Figure 15, highlighting only the extremes of the comparative analysis conducted on the titles, the interest in the topics carbon (Environmental), analysis and assessment (Economic), resilient (Social) and material, vernacular, and roof (Management and Development) is only confirmed for the pre-COVID-19 period. Post-COVID-19, on the other hand, confirms the strong interest in the topics emission (Environmental), residential (Social), plan, and smart (Management and Development). The eccentricities we can record, instead, concern a greater interest in the theme environment (Environmental), in the pre-COVID-19 period, and in the themes efficiency (Environmental) and design (Social), in the post-COVID-19 period. In addition, it is possible to detect the presence of the word challenges, a characteristic theme of post-COVID-19 recovery.

In any case, these eccentricities all involve themes that were in an equilibrium situation in the keyword comparative analysis and, for this reason, do not alter when previously deduced.

Figure 16, on the other hand, considers only the extremes of the comparative analysis conducted on the abstracts. In this case, except for the confirmation of the interest in the topic temperature (previously heat or thermal in Environmental) being only in the pre-COVID-19 period, we have the majority of confirmations for the three-year period 2020–2022. The topics renewable (Environmental), economic (Economic), global and existing (comparable, respectively, to world and heritage of the Social macro theme), and development and project (Management and Development) confirm what was previously deduced. Two eccentricities can be recorded in the post-pandemic period: adaptive and materials, both from the Management and Development macro theme. These two themes, like the eccentricities that emerged previously, are part of those already in the balance and therefore, again, do not contribute to altering the previous results. New words also appear in this analysis, mainly due to the discursive/descriptive character of the abstract. For example, the words needs, aims, and order could confirm an increasing need since 2020 for concreteness but at the same time could only be part of the discourse and, for this reason, have not been included in the reasoning from the comparative analyses described so far.

5. Conclusions and Future Developments

The analysis of the 90 papers extracted from Elsevier’s Scopus and MDPI’s Sustainability databases, according to the procedures described in Chapter 3, produced some interesting insights.

At the level of academic interest, we can start by asserting that the concept of sustainability and the problems related to the impact of climate change are both fast-growing research topics. In fact, taking into consideration the sample of articles examined, the number of papers published in the last 3 years has a similar weight to those presented in the 10 years prior to the advent of COVID-19.

Furthermore, it emerges that both are no longer topics of interest purely for the preservation of a few super-developed nations but have begun to interest the entire academic world through a more homogeneous distribution across all continents.

We can also state that, as has emerged from the comparative analyses conducted on keywords, titles, and abstracts, there is a clear demand for more practical and concrete solutions than in the past. The rise in the number of papers presenting the use of case studies within them can also help to support this fact. For the sample examined, papers supported by case studies increased from one in five in the period 2008–2019 to about one in four in the period 2020–2022.

The pandemic emergency has driven the world of research to focus not only on the technical–scientific aspects of the energy sector or on alternative architectural solutions (biomimicry, passive house, and vernacular) but to try to deepen the topics of clean energy (green), of zero emissions, and direct control of consumption. In this regard, the economic aspects seem to be starting to interest the research world more.

The comfort of residences has become a central theme in research papers, precisely because homes have once again become the centre of people’s private and working lives. The themes of comfort and design, highlighted in the comparative analysis of the third macro theme (Social), confirm the need that emerged with the advent of COVID-19 to introduce a new concept of the workspace. If, due to the mandatory lockdown caused by the pandemic, the home returned to being the centre of people’s working lives, in the post-pandemic period, the workers themselves tried to maintain at least some of the privileges acquired from working remotely. The Smart Working Observatory of the Polytechnic University of Milan, a research group founded in 2012 precisely to study the evolution of the way of working, affirmed that thanks to COVID-19, many companies have had the opportunity to try Smart Working, appreciating the benefits of the autonomy and flexibility of spaces and hours left to workers [119,120]. Obviously, for some kinds of jobs and/or companies, the possibility of growing the team of workers within their (well-defined) workplaces has always meant a further guarantee of success, precisely as a result of the fellowship and feeling that was established between colleagues. In order to meet the aforementioned company needs and to avoid displeasing workers by denying them their acquired privileges (during a dramatic period), in the post-COVID-19 period, the concept of the “Smart Office” has gained traction: a smart and continuously developing office (both themes emerged from the comparative analysis of the fourth Management and Development macro theme), where people’s work needs redesign the office space [121].

Another change, completely unexpected until just before the advent of COVID-19, is the return of researchers towards new constructions that can ensure better performance than renovations. Relating to construction activities, in addition, the needs, economic, materials, and global themes that emerged in the comparative analysis of the abstracts can highlight how much COVID-19 has changed not only the habits related to people’s daily lives but also the economic patterns of consumption and distribution worldwide. Restrictions on cross-national travel and shipments, implemented during COVID-19 and prolonged even during the post-pandemic period, generally generated higher costs of raw materials and, consequently, of finished products. The AEC sector, exploited by some nations as a booster for the post-pandemic recovery of their economies (e.g., Italy), has suffered a setback in planned interventions, about 50 percent, precisely because of the rising cost of construction materials [9,122]. For example, in Italy alone, comparing prices for the two-year period 2022–2023 with those for 2020, there was an increase of more than 70% for steel and lumber, 59% for concrete and cement, and 38% for bricks, mainly due to the cost of CO₂ emission rights and rising energy costs [122,123].

A further relevant fact that emerged is the introduction of the fourth macro theme (Management and Development), and its fourth P (planning), in the management and analysis of sustainability issues and data. This has made it possible to highlight the need—growing in the post-COVID-19 period—on the part of the scientific research world of the building sector to address the issues related to sustainability and the impact of climate change on buildings through a more integrated vision, which takes into account long-term planning and allows the observation of sustainability and sustainable development phenomena through a holistic approach, contributing to a better assessment of the social and economic impact of sustainability in the building sector.

Naturally, this article does not claim to be a definitive analysis of the issues relating to sustainability and the impact of climate change in the field of architecture and construction but rather an opportunity to reflect on the topic and possibly a starting point for even more in-depth analyses in the future. In this regard, one of the future developments hypothesised for this literature review is to expand the available data pool both by including new databases and by increasing the percentage of selected articles in the already-analysed databases. A further in-depth study could consider a division into three periods: pre-COVID-19 (2008–2019), COVID-19 (2020–22), and post-COVID-19 (2023–2025), which would make it possible to understand whether the interests that emerged due to the pandemic have maintained their appeal or, instead, have undergone a further change.