Sustainable Urban Heat Risk Resilience: Lessons on Opportunities and Barriers to Action from Colombo, Sri Lanka

Abstract

Cities face increasing heat risk due to global and local warming, and the risk is greater in the developing world. South Asia, in particular, faces increasing urban climate risk, but the translation of urban climate knowledge into sustainable climate-sensitive planning is weak. In this paper, we report on our conversations with experts from the Sri Lankan urban planning community on the barriers to and opportunities for urban climate mitigation action. We uncover six themes (insights, integrate, specify, exhort, commitment, and continuity) that best exemplify both the barriers to and opportunities for enhancing heat risk resilience in this primate city. We then map a set of agencies and actors that need to be involved in any holistic risk resilience plan and draw wider lessons to sustainably manage the urgent practical gaps in heat health planning.

1. Introduction

The increasing heat risk in cities is due to the combination of global climate change and the more local microclimate anomaly known as the urban heat island (UHI) [1]. Following the IPCC convention of ‘risk’ as a function of hazard, exposure, and vulnerability [2], the increasing urban heat risk is due to rising temperatures (‘hazard’), especially the wet-bulb temperature [3]; the increasing urban population (‘exposure’), especially in the developing world [4,5]; and poverty and lack of essential services (‘vulnerability’), particularly in the developing world.

The health and wellbeing consequences of urban warming are particularly problematic in South Asia. On the one hand, the relative share of urban warming, when compared to total warming, is very high in South Asia (reaching up to 76% of the total warming in cities such as Kolkatta, India [6], and averaging approx. 60% across the region [7]). On the other hand, rapid urbanisation, albeit from a low base (see Figure 1), and urban poverty magnify the risk. Approximately half of the urban population in South Asia lives in slums (see Our World in Data—https://ourworldindata.org/urbanization#urban-slum-populations, accessed on 27 October 2024).

The urbanisation and growth situation in Sri Lanka is particularly unique, as can be seen in Figure 1. Starting from a very low base of less than 20% till the end of the 20th Century, the recent growth in the urban share of the population, following the end of civil conflict in 2009, is rapid. Our previous work [8] has shown a particularly striking warming trend in Sri Lanka. Based on a thermal comfort index—the Universal Thermal Climate Index, UTCI—Sri Lanka’s average heat stress in the hottest month (April) is close to ‘extreme heat stress’, while the situation in the coolest month (January) is fast approaching ‘High heat stress’ across the country [8]. This work further showed that well-known urban climate mitigation options, such as shading and green cover, could reduce heat stress, even in the hottest month, but their utility will diminish unless climate change itself is moderated. Despite this and unlike elsewhere in South Asia (such as Ahmedabad, India), where recent heatwaves have led to the development of heat action plans (HAPs) [9], Sri Lanka does not possess a HAP at present. This is despite the warning by the Sixth Assessment Report of the Inter-Governmental Panel on Climate Change (IPCC), which stated that humid heat stress in South Asia will be more intense and frequent during the 21st century [7]. Although early efforts to develop heat health warning systems specifically targeted at urban areas are beginning to appear in India and Pakistan [10], these need to be deployed more widely across the region.

Urban planning and design approaches to managing heat risk in warm climates are widely known. Designing buildings to shade interstitial spaces is a possible approach to enhance outdoor comfort, as recognised by concepts such as the ‘Shadow Umbrella’ [11]. Promoting airflow is another approach to thermal comfort enhancement in warm climates by way of managing the form of buildings (e.g., courtyard form [12]), orientation of buildings along major ventilation axes [13], step-up form of building arrangement [14], and a combination of shading and ventilation approaches [15]. A third approach to overheating management in warm climates is green infrastructure (continuous tree cover in streets and [16] appropriate selection of tree species [17] in combination with shading [18]). High-albedo materials could contribute to mitigating the urban heat island effect in warm areas and improve thermal comfort in outdoor spaces [19,20,21], although evidence for their universal efficacy is weak [22,23,24]. Furthermore, land use morphological characteristics play a more important role in urban thermal environments than landscape patterns [25].

Yet, this knowledge remains poorly exploited in urban planning practice, particularly in South Asia. We hypothesise that the lack of exploitation of climate knowledge in planning is due to governance, policy and personnel-related challenges facing the urban planning community. Additionally, there may also be challenges related to the awareness of the magnitude of the heat risk and the rapidity of the changes in heat risk. Given the scale of the problem and the availability of climate-resilience knowledge, the present work aims to understand the existing administrative barriers to knowledge sharing in climate-sensitive urban planning and points of possible interventions to translate the available urban climate knowledge to planning practice.

2. Context

Colombo, the commercial capital of Sri Lanka, has had a long history of formal attempts to regulate its urban growth (see

Table 1. Relevant developments in urban governance in Colombo, Sri Lanka. Agencies are highlighted in green.

Year	Key Development
1865	Establishment of the Colombo Municipal Council (CMC)
1887	Forest Department was established as the Office of the Conservator of Forest
1921	City Plan by Sir Patrick Geddes City of Colombo: ‘The Garden City of the East’
1940	Plan by Clifford Holiday This emphasised controlling people’s movement through ‘Zoning’, which was assumed would regulate and stabilise the future growth of Colombo. Commercial, industrial, and residential areas were provisionally defined in this plan.
1948	The Regional Plan by Sir Patrick Abercrombie The plan proposed to decentralise city functions into three new satellite towns of Colombo City—Ratmalana, Ragama, and Homagama.
1951	Department of Meteorology
1966	The Ceylon Tourist Board
1968/1982	Sri Lanka Land Development Corporation (SLLDC)
1978	Urban Development Authority (UDA)
1978	UNDP Assisted Colombo Master Plan The Regional Structure Plan and the Urban Area Development Plan
1979	National Housing Development Authority
1981	Coast Conservation Department (CCD)
1981	Central Environmental Authority (CEA)
1984	National Building Research Organization (NBRO)
1985	City of Colombo Development Plan—developed by a UDA + UNDP team
1998	Colombo Metropolitan Regional Structure Plan (CMRSP) This plan was influenced by the three pillars of the sustainable development concept, namely, society, the economy, and the environment.
1999	City of Colombo Development Plan—formulated as an amendment to the Colombo City Development Plan of 1985. It was prepared based on the Core Area Plan of CMRSP, 1998; hence, it follows the planning guidance for the City of Colombo.
2001	The Ministry of Environment
2001	National Physical Planning Department
2004	Western Region Megapolis Plan Commonly known as the ‘CESMA Plan’ among planners. The objective of this plan was to make Colombo a modern city that would play a key financial role in the South Asian region.
2005	Disaster Management Centre (DMC)
2008	City of Colombo Development Plan (Amendment)
2008	Climate Change Secretariat Sri Lanka under Ministry of Mahaweli development and environment
2007	Sri Lanka Sustainable Energy Authority (SLSEA)
2009	Green Building Council The aim of the GBCSL is to transform the Sri Lankan construction industry with green building practices and fully adopt sustainability as the means by which our environment thrives, the economy prospers, and society grows to ensure the future wellbeing of our motherland.
2012	National climate change policy by the Climate Change Secretariat
2016	National adaptation plan for climate change

). Since the establishment of the Colombo Municipal Council over 150 years ago, ‘environmental’ matters (including forestry, disaster mitigation, public health, and, lately, climate) have been considered in the city’s many developmental regulations. While there is general awareness and consideration of Colombo’s tropical climate, the rapidly changing local climate is not well-acknowledged in the planning policy framework in Colombo or Sri Lanka as a whole. Our prior work [8] has shown that the hottest month (April) areas that were previously classed as ‘very strong heat stress’ in the 1990s are moving towards ‘extreme heat stress’ in the 2010s, covering over two-thirds of the landmass of Sri Lanka. Even in the coolest month (January), ‘moderate heat stress’ unknown in the 1990s is now becoming a common trend across the most densely populated regions. This work further showed that high shading and vegetation levels could reduce heat stress, even in the hottest month, but their utility will diminish as the warming continues in the future. As will be seen in Section 4 below, our informants were very clear that this type of local climate considerations is not integral to the planning approach in the city.

3. Materials and Methods

We conducted an in-depth inquiry into the lived professional experiences in climate-sensitive planning in Sri Lanka to explore subjective viewpoints. Expert opinions were sought out, and semi-structured interviews were conducted.

Our starting point was the previously published work [8], which clearly showed the warming trends in Sri Lanka and the possibility of arresting them through known urban climate mitigation strategies, such as shading and vegetation. We conducted a pilot study to disseminate this work among a large group of urban planning professionals (forty) and to gather practitioner thoughts on key challenges that needed to be explored more in detail with experts. The pilot work also helped us identify experts with direct experience in the Sri Lankan urban planning system. Given that our purpose was to develop a nuanced understanding of the ground realities in climate-sensitive urban planning practice (or lack thereof), we used the leads arising from the pilot study to reach out to experts with direct experience of the Sri Lankan urban planning system (and in particular, its interactions with climate-sensitive planning sub-domain). Thus, a purposive sample, rather than a random sample, is appropriate for the present purposes. We used a ‘semi-structured’ approach to the interviews, in which a list of key points identified in the pilot study formed the basis of the interviews. We then presented to the shortlisted experts our findings on the country’s urban thermal comfort trends and the likely effect of selected planning strategies to mitigate the trends. This led to four broad categories of questions: Colombo planning context, climate change in Sri Lanka, climate-sensitive design strategies, and the implementation of design interventions in urban planning. These helped to inform the interview questions (around thirty).

The themes and the ‘semi-structured’ approach facilitated the smooth flow of the interviews and helped us work through them in a methodical manner. While we asked similar questions of all interviewees, supplementary questions were asked as appropriate. We aimed to cover all nine types of interview questions specified by [26], although the interviewees were free to respond as they pleased and did not have to ‘tick a box’ with their answers.

Using a snowballing approach from our large pool of pilot study participants, we settled on six experienced professionals who have contributed to shaping the planning landscape in Sri Lanka for interviews—two each from the academic (AC), practitioner (PR), and administrative (AD) communities. A summary of interviewee characteristics is tabulated below (

Table 2. Details of interviewees.

Attributes	AC1	AC2	PR1	PR2	AD1	AD2
Profession	Academic planner with climate change adaptation experience	Academic with a social science background	Practitioner planner with private practice expertise	Practitioner urban designer	Regulatory personnel	Regulatory personnel
Years in industry	30+	15+	30+	25+	20+	30+
Worked in authoritative positions?	Yes	No	Yes	No	Yes	Yes
Investor relationship	Yes	No	Yes	Yes	Yes	Yes
Worked in national organisations with a climate mitigation mandate?	Yes	Yes	Yes	No	Yes	Yes
Highest academic qualification	PhD	PhD	MSc	MSc	PhD	MSc
Involved in approval of development plans?	Yes	No	Yes	No	Yes	Yes
Involved in creating and promoting development plans	Yes	No	Yes	Yes	Yes	Yes
Practical application of development plans	No	No	Yes	Yes	No	Yes

).

We conducted one-on-one online interviews during the months of March to June 2021 and each interview lasted around 60–90 min. Open-ended questions were asked mainly to focus on the existing planning context and urban climate in Colombo.

The interviews were then analysed using thematic analysis. Thematic analysis is a popular method of qualitative analysis that explores insights through patterns of meaning (themes) that occur around a dataset by systematically grouping and organising it [27].

Since the pioneering attempt to outline a pragmatic view of thematic analysis [28], several methods have emerged on how to perform a proper thematic analysis that could be applicable to a wide range of research areas. We followed a six-phase approach to thematic analysis [27], as follows:

• Familiarising yourself with the data;
• Generating initial codes;
• Searching for themes;
• Reviewing potential themes;
• Defining and naming themes;
• Producing the report.

All interviews were recorded and automatically transcribed using Microsoft Office software Ver. 10.0 (Word Web app). The transcribed files were then coded, initially using the themes derived from the pilot study. The search for themes and review of potential themes were facilitated by NVIVO-12 pro software, which enabled the grouping and re-grouping of hundreds of codes to achieve a coherent set of themes. This was performed at the end of each interview. By the end of five interviews, we reached the saturation point, and the sixth interview merely repeated the derived codes. This reinforces our view that all major points addressing urban climate mitigation actions are covered by the interviews. Hence, Section 4 presents only the first five interviews.

4. Results

4.1. Themes—An Approach to Implementation

The thematic coding results provide ‘meanings implied’ and insights into the nature of the current planning environment and strategies to integrate climate-sensitive planning into the overall urban planning process. The themes and subthemes generated from the analysis are depicted in Figure 2 below.

4.1.1. Insights—Through Research and Data

a.

Through research

One of the questions aimed to gauge existing climate knowledge in Sri Lanka, for which we obtained mixed answers from the participants. Two participants clearly identified the need for contextualised local research: ‘most of the studies are very general studies, where we can’t make any decisions’. Since the importance of context can never be underestimated in climate studies and strategies [29], it is important that academia encourages more specific studies that contribute to practical applications (See

Table 3. Details of Theme 1.

Name	Files	References
Insights—through research and data	5	23
Through research	1	9
Through precedence	1	6
Through data	3	8

).

Similarly, the quality of research is important. One of the practitioners, PR1, identified that there was limited research on the local urban climate, and the quality of research seems to be less focused and ineffective when formulating ground-level solutions and attributes.

The need for quantitative research was stressed by AC2, who claimed that quantitative research can sometimes be isolated, assumption-based, and obtained with erroneous or manipulated data.

b.

Through precedence

Throughout the interviews, there were references to the pros and cons of precedence from other countries. Some encouraged ‘learning lessons from other cities without reinventing the wheel’, while others claim that precedence can only be a starting point and not the end results of implementation due to different local perceptions. PR2 stated, ‘We need to have our own system of determining these things—our comfort level is completely different for a person in Europe. Their comfort level may be too cold for us. Thus, we need contextualized modification of urban climate parameters, rather than borrowing from the West’.

One participant further claimed that solutions based on other countries should be critically questioned prior to implementation in our context considering our socio-economic and geographical context. They stated ‘You can’t compare Singapore and Hong Kong with Sri Lanka, their mindset is different, the focus is different… these are high density, well-developed cities. The Megapolis Development Plan (Govt. of Sri Lanka, 2004. Western Megapolis Master Plan, https://www.jll.com.lk/en/trends-and-insights/investor/western-megapolis-master-plan, accessed on 27 October 2024) is a failure as we have tried to imitate Singaporean designs’.

c.

Through data

Ref. [30] defines the three components of knowledge as data—the lowest point, an unstructured collection of facts and figures; information—structured data; and knowledge—information about information. Although we can gain a lot of insights through data, organised ways of storing, categorising, and centralising data for future use (i.e., information) are key to knowledge in the current context.

Both practitioners we interviewed asserted the importance of having data recorded and available in a centralised databank for future use. This could be past climate disasters, surveys, reports, modelling exercises, simulations, etc. They also stressed the importance of coordinated data and having previous models/simulations available for use by future designers.

PR2 contended that the data collated by the meteorological department stand in isolation and are not utilised by the Urban Development Authority (UDA). This is similar to what other researchers found previously (e.g., Ref. [31] calls for the integration of meteorological data in the planning system for useful urban climate actions.)

4.1.2. Integration—Policy, Authorities, and Expert Opinion

a.

Integration—Bread and butter OR roof and shade?

When we discussed the opportunities for prioritising urban climate-sensitive decisions in the planning process, most participants qualified that ‘we need climate actions, but there are other priorities…’, where the priorities are social and economic challenges. Thus, we coded this theme in the integration of urban climate policies as a ‘second-order planning decision’ (See

Table 4. Details of Theme 2.

Name	Files	References
Integration—policy, authorities and expert opinion	5	59
Policy level interventions	5	37
Integrate administrative departments	3	7
Integrate expert opinion	2	7
Public consultation in planning	3	8

).

‘Unless we integrate social, financial and cultural benefits, implementation of climate mitigation strategies will tend to fail’. –PR1.

The key challenges that govern the planning landscape, as posited by the participants, are social—especially housing, transport and waste management.

AC1 stated that ‘… there is more than 50% of under-served settlement in Colombo. There has been a long-term agenda in addressing this, but still we have failed to find a successful solution…’. Echoing the same idea and adding depth to it, AD1 stated that ‘… Colombo is a wetland-based city—we need to plan based on the ecological strength of the city. These wetlands provide ecosystem services, but encroachment into wetlands and marshes has posed a serious threat’.

Encroachment and urban sprawl are serious problems in Colombo that have not been addressed adequately in the past [32,33]). AD1 stated that ‘Colombo being the primate city has attracted a lot of demand pressure over the years. Infrastructure development, transport, waste management have been unresolved issues for decades, and the high demand for development will only make it more challenging in addressing these’.

However, there was agreement that we need to cater to this demand. Commenting on the existing regulations as ‘restrictive in nature’, AC1 stated that planning regulations must consider market forces and allow optimum built form, thereby encouraging developments.

The discussions also highlighted the crucial necessity to address climate disasters, such as urban flooding, landslides, the degradation of air quality, etc., through planning practices. AC2 acknowledged that urban warming mitigation should be a priority in planning but must be integrated with other policies. There should be a balance, as ‘…ultimately it all boils down to the bread and butter of common man …’ (PR1).

When discussing the key concepts within sustainable development, [34] recognised that social and economic practices are inseparable from sustainable development. Sustainable development needs to be integrated within socio-economic policies. This is also advocated by the New Urban Planning—Vancouver Declaration [35]. However, by prioritising climate mitigation strategies, countries can minimise unnecessary economic burdens associated with post-disaster recovery and establish a healthy workforce. This leads to a debate about whether climate mitigation strategies should be considered second-order strategies or first-order strategies, especially in a developing country like Sri Lanka, due to the fact that neglecting climate risks has led to severe climate disasters in the recent past.

b.

Policy integration—top-down/bottom-up

While discussing whether urban climate actions can be governed, PR1, AD1, and AC2 stated that they can easily be governed from a top-down approach due to the structure of urban governance in Sri Lanka. The command-and-control structure makes it relatively easy to impose regulations that will trickle down to ground level.

On the contrary, AC1 and PR2 stated that urban climate actions should be governed using a bottom-up approach. Even though policies are imposed, they could be easily manipulated by the ‘middle management’, i.e., regulatory agencies, which have the power to thwart implementation. Due to corruption and malpractice, this might not be implemented effectively or rather end up only in documents. However, if the public is aware of the adverse climate effects and there is a strong desire to carry out climate action among the people, the middle management will also feel pressure from the bottom.

AD1, AC1, and PR1 insisted on the need for public participation in the planning process. PR1 said that the Indigenous knowledge of traditional architecture was very much based on thermal comfort, and the planning process can and must gain insights from them. Additionally, AC1 indicated the need to involve the public to dissipate climate knowledge and make them aware.

c.

Integrate expert opinion

The interviews confirmed that integrating professional inputs at the beginning of the planning process and integrating them throughout the implementation process is a positive reinforcement in urban climate mitigation strategies.

PR1 said that ventilation modelling for downtown Colombo revealed that high-rise buildings could actually improve the wind flow of the city. These sorts of evidence-based revelations can help create a thermally comfortable environment while at the same time encouraging development, thereby creating a conducive environment for attracting urban investments.

PR1 and AD1 suggested that it would be necessary to have a town planner-led assessment that consisted of all necessary checkpoints—climate, environmental, material, urban warming, waste management, etc. We were also told that this has been proposed by the UDA as a measure to integrate professional input in planning but has not yet been implemented.

Apart from policymakers approaching professionals, professionals should also take the initiative to voice their opinions. We categorise these suggestions under Theme 4—‘Exhortation’.

This is similar to other suggestions found in the literature. For example, with the growing importance of sustainable urban planning, policymakers and planners are responsible for identifying thermally vulnerable areas in the city, and they plan accordingly, which requires knowledge and expert input [36].

Based on recent experience in leading a new urban development proposal, one of the participants claimed that the new proposal better integrates expertise from various fields and utilised holistic and contextualised solutions, such as green areas along water bodies to mitigate urban warming. They further stated that ‘although there are claims of many sustainable developments, most of these don’t integrate expert opinion at the very beginning and are often add-ons which is often a makeover/afterthought process’.

d.

Public consultation

There was a strong consensus that public consultation should be a key part of climate-sensitive and sustainable planning. AC1 stated that involving the public during the planning process will not only allow Indigenous knowledge to integrate with planning but also allow the public to be informed regarding the benefits of climate-sensitive planning and design. They further pointed out that there is no existing system in the planning process in Sri Lanka that informs the public regarding neighbourhood development and that if the locals are informed and involved in the planning process itself, there could be more control over developments.

AD1 and AC2 both implied the need for regulating public consultation as a mandatory requirement in the planning system for effective climate mitigation strategies. This finding is similar to that of the authors of [37], who researched inclusive approaches to urban climate adaptation planning and implementation in the Global South. They found that participatory approaches lead to higher climate equity and justice outcomes in the short term, whereas integrating multi-sector organisations will lead to long-term programme stability.

e.

Integration of administrative institutions

One of the significant barriers we identified in implementing climate-sensitive planning is the fragmentation of administration and thus institutional decision-making. This was brought up by all the participants and thus led to the easy identification of a subtheme.

When we inquired about existing climate awareness amongst stakeholders, PR1 said that while there is a considerable knowledge base, this is not being effectively implemented, mainly due to the existence of several planning agencies with overlapping responsibilities.

PR2 indicated that the implementation of development plans is ‘not even 50% efficient’ and indicated the fragmentation of institutions as a key reason for this. ‘The NPPD (National Physical Planning Department) develops plans at the national level, but these are not backed by financial plans. They only work within their own scopes. Thus, the plans mostly end up in only documents’. PR1 also indicated that the separate Climate Change Secretariat and Environmental Ministry are not synchronised in an effective way to provide solutions. Further, they indicated that this can lead to finding a loophole rather than consciously responding to the situation.

This is consistent with what the authors of [38] found when analysing the structure of policymaking in Australia. They stressed that consistent and coherent development plans are achieved through the coordination of central agencies and identified that these agencies are vital to the task of policy coordination.

4.1.3. Specify—‘God Is in the Details’

This was the most referenced theme, with 68 references throughout the interviews, and it was constructed with ideas revolving around ‘lack of detail’ and ‘the need for conscious specified regulations’ (See

Table 5. Details of Theme 3.

Name	Files	References
Specify—God is in the details	5	68
Vague guidelines	4	19
Macro to micro	4	21
Picking low-hanging fruits	2	3
Strategic solutions	5	25

).

a.

Vague guidelines—no focus

All the participants explicitly stated that existing regulations were very vague and not detailed enough. AC1 and PR2 suggested that the development plans were not focused on urban climate issues, and PR2 further elaborated that ‘…the existing development plan is not adequate to address climate issues, let alone other issues such as transport, waste management etc…’ and ‘… the CDP (Colombo Development Plan) is very generic and not specific, I would say that CDP is more a regulatory plan than a development plan…’.

Local authorities and the UDA control most developments in Sri Lanka. The CDP is the ground-level guidance for any development in Colombo, and specifying this in detail will allow for more control over development.

b.

Macro to micro

The existing development plans were identified as mere zoning approaches that needed much more detail.

AC1 stated that ‘The current plan is limited to only zoning and building heights, and since there are no specific guidelines, one can easily manipulate the regulations, especially investors and politicians’. PR1 and PR2 also acknowledged that existing zoning-based guidelines could be easily manipulated. AD1 stated that zoning was a good initiative but must be detailed.

AC1, PR1, and PR2 discussed moving to the ‘next level’ of zoning—developing regulations for districts, neighbourhoods, streets, etc. PR1 and AC1 said that we need to consider detailed design guides for clusters or neighbourhoods while developing regulations to address UHI/UW issues. They elaborated on this, stating the following:

‘…our building regulations are single entity focused—the concerns are only the plot. Spaces in between the buildings are not covered. Wind flow within neighbourhoods, shading effect from adjacent buildings etc. are not considered…’–PR1.

PR2 further stressed the need to consider smaller districts in planning while drawing examples of Singapore planning, in which guidelines are based on smaller areas and lead to more sensible plans.

Through the interviews, we understood that classifying building typologies could be an effective method for developing regulations. PR1 indicated that we should change the paradigm of how we look at our building regulations to implement effective detailed guides, as follows:

‘…our regulations are more land oriented—land-use based. If we are concerned about these heat island and urban warming issues, we need to focus more on building typologies rather than land uses. We need to address these issues at a policy level’.

The issues in the existing guidelines were discussed in detail. Our informants felt that they are developed on a broad zonal basis (i.e., the whole city) and/or focus on building scale (in terms of setbacks, energy consumption, etc.), leaving the middle ground (policies focused on the interstitial spaces) largely uncovered.

c.

Picking low-hanging fruits

When discussing the urgency of climate-sensitive planning, we understood that the preparation of detailed guidelines will take time. PR2 and PR1 suggested implementing a ‘hassle-free planning process’ for smaller developments. This can be detailed to encourage urban climate mitigation, such as retrofitting existing buildings to encourage shade, greenery, etc., and converting impermeable material to permeable/thermally reflective materials, etc.

Integrating climate checkpoints can also be attributed as immediate measures to tackle the incorporation of urban climate actions and will also create awareness amongst professionals and the general public. AC1 suggested incorporating the town planner’s assessment and accepting it as a requirement by donor agencies as an immediate measure.

d.

Design strategies

We constructed this subtheme as a summary of all design strategies discussed during in-depth discussions. Firstly, we solicited interviewee opinions on four well-known urban climate mitigation strategies (

Table 6. Interviewee responses to known urban climate ameliorating strategies.

	Urban Form	Vegetation	Wind flow	Albedo
AD1	0 Somewhat through plot coverage, FAR	+1 - ‘Garden city’ concept - Regulated through plot coverage	−1 No consideration	−1 No mention
PR1	0 Somewhat through plot coverage, FAR No conscious effort	+1 ‘Colombo is still green’ through plot coverage and reservations	−1 Planning guidelines are single entity-focused. Wind is not considered.	−1 ‘No materials specifications at all’
PR2	−1 Plot cover, FAR does not imply positive climate action. We need to specify	−1 Might/might not grow green on their premises. If the plot coverage is 65% you cannot expect the other 35% to be green.	−1 Seafront developments enjoy the wind flow, but it has not penetrated the city. No mention in documents.	−1 No mention in documents
AC1	−1 Development plan/building regulations do not regulate the urban form climate responsiveness.	+1 Maintain garden city character.	−1 Not considered in planning	−1 No mention in documents
AC2	−1 Possible unfavourable conditions due to unregulated building height, streets, zone issues.	−1 Very first plan promoted green. Current plan does not mention green.	0 Low densities allow for more air circulation, sometimes indirectly helping wind flow.	−1 No mention in documents
Key
		+1	Favourable
		0	Neutral
		−1	Unfavourable

). We then explored local climate mitigation ideas at different scales (regional/local/building-scale) that are specific to Colombo as given in the Colombo Development Plan (

Table 7. References to design approaches in governance documents (listed in Table 4) at different scales (regional, local or micro level).

	Urban Form	Interview Discussions	Literature	Planning Documents
Regional/City level	- Revisiting the notion of urbanisation developments of regional or satellite towns rather than concentrating on Colombo	x
	- Considering cooling potential of river (Kelani River), canals around Colombo, large green areas when designing the street networks. Likewise, other cities in Sri Lanka could be designed considering large water bodies—lakes, reservoirs, and forests.	x
	- Colombo is in the coastal belt. Streets and plots to be designed allowing the sea breeze and monsoonal wind.	x	x
	- Develop a blue-green network in Colombo	x
	- Transportation network could be designed in the periphery of the city centre, allowing limited number of vehicle fleet to the city while forming ventilation corridors to penetrate wind (this is beyond the research scope).	x	x
	- Seafront developments with low height profiles and low density, allowing wind flow into the city.	x	x
	- Special developments with high rises and multi-storied complexes should designed with blue-green features while not hindering the neighbourhood developments.	x	x
	- Buildings around the water bodies and open/green spaces (Galle Face Green, Beira Lake) could be designed low-rise allowing the air movement/cool breeze to the adjacent neighbourhood.	x	x
Local/Street level	- Area-/street-specific guidelines should be developed in detail. (Building height, street width, position of trees, etc.)	x
	- Incorporate wind direction and patterns when developing zoning plans and designing streets.		x
	- Determining the plot size and orientation at different zones to maximise the airflow and green cover, e.g., longer frontage in parallel to wind direction while matching the market forces.	x	x
	- Promote green network within the streets—green corridors and tree lines along the pedestrian access and vehicular routes to enhance shading that will promote walkability.		x
	- Provide green pockets in every neighbourhood	x	x
	- Incorporate green factor calculations in development projects.		x
	- Placement and selection of trees (height, canopy size, type of trees, and tree intervals) to provide shading, thermal comfort, and pollution filtering with minimal hindrance to wind flow (need more research on this area).	x	x
	- Provide waterbodies in communal spaces for evaporative cooling.	x	x
	- Determine the aspect ratio to increase shading by the building itself (some parts of Colombo have already realised this aspect) while at the same time not leading the air pollution.	x	x
	- New streets could be designed in north–south orientation, as they perform better than EW. However, existing streets cannot be changed, so shading devices could be designed for existing streets.	x	x
	- Cool materials should be applied for urban paving rather than avoiding concrete paving. Increase permeable areas—grass paving for parking and pedestrian walkways.	x
	- Promote community-level garden (urban farming); it accomplishes dual purposes.	x
Building/micro level	- Creating a balance among site coverage, building plot, and open spaces to maximise the green cover efficiently.	x
	- Defining the building setback and rear spaces with vegetation cover	x
	- Provide site-specific details (landscape details, green percentage, adjacent plots details) at planning clearances	x
	- Building position and orientation to cut solar radiation and promote airflow around the building.		x
	- Terraced podium/building form design to allow airflow. Design porous (gaps, openings) building.	x
	- Provide arcades, awnings, and other shading devices at the ground level for pedestrian comfort.	x	x
	- Introduce Energy Performance Certificate (EPC) for the buildings. Make this certification compulsory for new buildings and provide retrofitting solutions for old building stocks. Energy-efficient buildings positively affect the outdoors (in and out are linked and mutually affected).	x	x
	- Introduce national building codes (NBC)– specify thermal reflective materials, colours, and paints that enhance reflectivity.		x
	- In commercial areas, advertisement boards and sign boards are to be placed so as not to block the wind flow.		x
	- Educate people on outdoor working time. Avoid workers in afternoon hours when the solar angle is high, and continue in the evening.	x

). The former was suggested by us and was based on the literature, as outlined in Section 1 of the present paper, while the latter was jointly developed based on the literature, as well as local development plans.

Table 7 confirms that most of the design strategies mentioned by the interviewees were similar to those reflected in the urban climate literature. However, these were not captured in the development plans of the city (such as the CDP), which has been deemed a huge gap in the existing planning regime.

4.1.4. Exhortation—Shout Out, Convince, Urge

Exhortation means to strongly encourage/urge someone to do something. Urban climate action is a collective measure, and thus will not be effective unless a strong persuasion is involved, especially in the Global South, where the primary concern of the majority revolves around ‘bread and butter’ issues of livelihoods (See

Table 8. Details of Theme 4.

Name	Files	References
Exhortation—shout out, convince, urge	5	40
Incentivise	3	11
Create awareness	3	29

).

a.

Incentivise

PR1 stressed on several instances during the conversation that climate-sensitive design approaches should be tied to benefits—specifically financial benefits—to encourage uptake. These could be incentives, subsidies, loans, tax concessions, etc. They also addressed the lack of motivation to implement other good practices in the current development plan. This way, a developer can give something to the city while benefitting financially from the development.

b.

Creating awareness

All participants implied that awareness is a requirement for successful urban climate action. AC2 stated that ‘making people aware and convincing politicians’ is essential to practically incorporate checkpoints; if not, they might end up as mere checkpoints to gain a tick in the documents.

AC1 reflected on the abovementioned idea, further stressing that communication strategies should be tailored according to the target groups, i.e., the public, professionals, and investors, accordingly, rather than mass communication strategies. The same message can be delivered via different formats to different groups. They also implied that it is the responsibility of the professionals to voice their inputs and opinions to bring change to the system.

When discussing the possibility of a change in the planning system with a focus on urban climate actions, AD1 advocated the integration of climate awareness and heat-related health issues in the education systems as follows:

‘We can’t bring change overnight. But we can educate the future generation. I strongly believe if there is a programme to integrate this to our education system, we can make a big change in 5–10 years’.

4.1.5. Commitment—Act upon the Word

We constructed this theme out of discussions surrounding the lack of commitment towards a climate-oriented goal and profession, which poses a threat to pursuing sustainable urban climate actions (See

Table 9. Details of Theme 5.

Name	Files	References
Commitment—act upon the word	4	30
From document to practice	4	10
Political will	3	8
Professional ethics	2	10
Public commitment	2	2

).

a.

Commitment—from ‘document to practice’

Sri Lanka is a party to many international commitments to tackle climate change, such as the Kyoto Protocol. However, AC1 indicated that no effort is made to meet these commitments—‘we have nice set of documents, but nothing visible in practice’.

Further, PR2 and AC2 also indicated that checkpoints and assessments tend to exist only in documents and not in practice. PR2 said that ‘… the existing green building council rating focuses only on a rating system which has a minimum requirement, and once achieved, performance is not checked at the end…’.

While it is the responsibility of the relevant authorities to ensure the commitments are met, PR2 advocated global fairness as a consideration for policymakers to consider prior to undertaking such commitments, considering the country’s economic and social conditions.

b.

Professional ethics/public commitment/political will

A layman’s first point of contact with expert opinion is the professionals—planners, architects, designers, etc. AC1 stated that ‘if planners and architects consider their job at a more responsible and ethical angle, definitely these strategies be incorporated…, can be seen as an effective bottom up approach’. They also stated that professionals have the ultimate responsibility to advocate for urban climate action to the general public, investors and politicians.

‘Similarly, the public should also act responsibly’, said PR2. ‘When a fine imposed for littering the roads, the public obeyed; and once the implementation was stopped, they went back to their old habits’, providing an insight into the public mentality.

All interviewees strongly suggested political will as an important factor for successful UC action. PR2 stressed that it is again the professionals’ responsibility to convey the benefits in terms of financial benefits and advocate the benefits of urban climate actions.

4.1.6. Continuity—’Rome Was Not Built in a Day’

The theme of ‘continuity’ implies the notion of the continuous improvement and review of planning, policy, audits, and data in urban planning and governance (See

Table 10. Details of Theme 6.

Name	Files	References
Continuity—‘Rome was not built in a day’	4	24
Policy continuity despite regime change	4	9
Inception to completion: audit	3	5
Periodic review	2	10

).

a.

Policy continuity despite regime change

We constructed this subordinate theme with explicit notions indicating that political interference has an influence on genuine planning attempts. One participant noted that ‘There are government agencies such as Climate Change Secretariat, Sustainable Development Authority etc. to maintain climate commitments and actions. But these are discontinued with government changes and regime changes’.

Similarly, others also reflected that all genuine efforts of planners and policymakers go astray due to political interference and regime change.

b.

Audit: inception to completion and during use

Suggestions regarding the continuous monitoring of events in planning from inception to completion led to the generation of this subordinate theme.

When indicating effective means of regulating the built environment, AC1 said that ‘We can add climate checkpoints to enforce climate sensitive planning, but this again becomes only a permit—it will end up only in documents and not in practice. Hence, there must be an independent assessment, even during construction’. PR1 also resonated with this, saying that ‘There has to be a continuous audit system which monitors the construction from planning to completion’. They further indicated that the planning bodies lack the resources to undertake a successful audit.

Monitoring, evaluation, and reporting (MER) is a process that has been stressed for the fruitful outcomes of policy, plans, or projects [39] and has been proven to be an essential practice to ensure the project objectives while enabling flexibility [40].

c.

Periodic review

The subordinate theme, ‘Periodical review—planning’, implies that development plans should be continuously reviewed. There were repeated ideas emerging from the interviews; ‘we have an outdated plan’ and ‘we need a development plan that fits our context’ were heard a few times throughout the interview. As a planner and an administrator, AD1 insisted that the plans must be reviewed every 5–10 years and adopted according to the context; instead, the current development plans and regulations still cater to the ‘last decade’.

Both practitioners had similar concerns about adopting a development plan that caters to the ‘actual trend’. Other participants also implied that the land use method used in the current system must be re-examined; we discussed this under the theme ‘Specify’.

We combined all the interview scripts, ran a query for the 250 most frequently occurring words, and generated word art (Figure 3). The emphasis is clearly on the need for ‘awareness’ and ‘detailed plans’, further reinforcing the idea of social and political influences in urban climate actions.

Throughout the interviews, we identified several barriers with regard to implementing an effective solution to urban warming. We categorised them as political, social, economic, and other barriers (

Table 11. Summary of barriers to climate action in Colombo.

Summary of Barriers
Political barriers
- ‘Planning is essentially a political process’ (AD1) - Lack of political will. - Challenges in lobbying politicians to implement the interventions (AD1) - Political manipulation in environmental authorities and climate activists—planning authorities as political puppets (AC1)
Economic barriers
- Lack of funds for Colombo (AD1 and AC1) and climate-related projects (PR2). - No funding plans for climate change projects, even in the National Physical Development Plan. (PR2) - Investor reluctance (PR1 and PR2) - Primary concern is bread and butter, not the environment (AD1) - High construction cost (PR2)
Social barriers
- Lack of awareness (AC1, AC2, AD1, PR1, and PR2) - Colombo—a real estate bubble - Ad hoc development: ‘More than half of Colombo developments are illegal’. (PR1) - Corruption (PR2 and AD1) - Reluctant to change from the traditional building construction (AC1) - Urban poor, underserved communities, and no attention to urban warming
Other barriers
Policy-related barriers: - No specific legislation or policy guidelines to address the negative effects of climate change/urban warming issues (PR1, PR2, and AD1) - Vague development guidelines (inefficient/could be manipulated) (AC1, PR1, and PR2) - No enforcement plans (PR1, PR2, and AC2) - Corruption and bribing (AD1 and PR2) - Green building rating system in Sri Lanka is business-oriented (PR2) - Stagnated policy or rules—authorities are not updated (PR2 and AC1) Resource-related barriers: - Limited knowledge of urban climate among professionals and local authorities (AC2, PR1, and PR2) - Lack of guided climate research focus (AC2, PR1, and PR2) - Scattered/under-optimised data (PR2) Organisational: - Fragmented authorities—not synchronised (AC1, AC2, PR1, and PR2) - Unqualified professionals’ administration (PR2 and AD1) - Understaffing/lack of manpower at institutions (PR1, PR2, and AD1)

).

Similarly, we also identified opportunities for the implementation of urban climate actions and categorised them according to the identified themes (

Table 12. Summary of opportunities for intervention.

Summary of Opportunities
Insights
- Incorporation of knowledge informed by research data, mapping, modelling, etc., in planning and design decisions (AC2 and PR2) - Develop cross-border relationships—lessons from other countries (AD1 and PR2) - Meteorological data to be facilitated to the authorities and designers (PR2)
Specify
- Detailing plans at the neighbourhood level (PR1, PR2, AC1, AC2, and AD1) - Town planners’ assessment certificate (climate-sensitive assessment) (AD1) - Implementations: First identify the small interventions and make a flexible planning system to implement them (PR1). - Retrofit old building stocks responding to urban overheating (AD1). - Introduce energy performance certificates for the buildings (PR1).
Exhort
- Develop awareness: - Actions to increase the sense of urgency for the urban climate—proper communication system (AC2 and AD1) - Incentivised planning system—financial incentives (PR1 and PR2) - Environmental solutions designed to attract investors and politicians (PR2) - Strengthen enforcement (PR1) - Initiate public buildings—government buildings as a showcase (AC1) - Exploring low-cost solutions for short-lifespan urban regeneration (AC1)
Commitment
- Climate assessment as a requirement at donor funding bodies—banks, finance agencies, etc. (AC1) - Introduce climate checkpoints system in design and construction (AC1) - Committed to Green building rating system (PR1 and AD1) - Advocating for an effective bottom-up approach for UC governance (AC1)
Continuity
- Periodical review and update the plans every 10 years at least (5 years recommended) (AD1) - Make plans to continue, despite the political regime change (AD1). - Monitoring, evaluation, and reporting (MER) of the plan (PR1 and AD1)
Integrate
- Urban climate-related policies integrated with other socio-economic and environmental policies (AC1, PR1, PR2, and AD1) - Climate-sensitive plans should be embedded in the National Physical Plan and finance plan (PR1 and PR2). - Public participation (AD1 and AC2) - Relevant authorities should be integrated and involved in the planning, designing, and decision-making processes (PR1, PR2, and AD1). - Meteorology department should be linked with policymakers and other authorities, including universities, because now met data is in isolation (PR2) - Lean governance of data in planning (AC1 and PR2) - Need collaboration between climate research and urban designers (PR2) - Climate studies should be incorporated into the curriculum—educational system (AD1, PR1, and PR2)

).

5. Discussion—Who Should Be Involved?

Urban warming is an issue that cannot be viewed in isolation but needs a holistic approach within the development agenda. Apart from the efforts of the epistemic community, a practical approach requires integrating all socio-political actors and institutions. The need for a proper network amongst stakeholders related to planning, infrastructure, and building construction was strongly emphasised during interviews.

While professionals play a guiding role in proactively guiding the public and exhorting the government, the public and politicians should also support their efforts. We could also investigate resolving the fragmentation of institutions as a primary objective while looking into encouraging policy initiatives gradually. Financial institutions and banks can also play an important role in regulating the built environment by stipulating financing conditions.

Figure 4 aims to capture the stakeholders that need to be involved (core—blue boxes and periphery—green boxes), identify agencies and individuals that could effect the necessary changes (purple boxes), and provide a set of exemplary policy prescriptions (yellow ovals). These are clustered around three scales of potential intervention—urban planning, infrastructure, and building scales. These scales are in line with the findings of [37,38]. The grey boxes present the many challenges and bottlenecks identified by our interviewees as major causes for urban climate inaction and by clustering actors and policies around the key challenges; we have attempted to identify specific pathways of implementation, key actions, and policies that are needed to enable these interventions and actors and agencies that should be tasked with the implementation. Further work is needed to flesh out specific implementation plans and feasibility analysis under different socio-political contexts. The examples provided in Figure 4 for the Colombo context, together with previous work by [37,38], could serve as a template for embedding urban climate knowledge in urban planning.

6. Wider Implications

As the world continues to warm, cities (in particular developing cities) face twin problems. On the one hand, urban climate science remains under-represented in the assessment and mitigation of global climate change. On the other hand, existing knowledge of the urban climate is not well-integrated into sustainable urban development policy and planning. The case of heat resilience planning (or lack thereof) in Colombo, Sri Lanka, serves as a warning and a learning point for other developing cities. Urban overheating is already at the thresholds of tolerance (i.e., ‘extreme heat stress’) in many parts of the world [3], and this is also true in Sri Lanka [8]. While the need for embedding urban climate knowledge in the wider global climate science is ever more pressing, cities need to act now to enhance their sustainable survival to avoid placing unnecessary economic burdens on already economically stressed societies. Urban climate design strategies can result in improved microclimate, but this should be integrated with the socio-economic enhancement of urban dwellers (through actions to address underserved settlements, poverty alleviation, urban regeneration, etc.) and incorporating socio-political actors (planners, professionals, politicians, the general public, etc.). Specific implementation plans that explicitly address the barriers identified in the present work are needed, and their feasibility will depend on the local context.

‘How’ to achieve this needs more intense scrutiny, but we need to be mindful of context-specific scientific and sociological data. Urgent action is needed to arrest the worsening heat stress in cities. The local monitoring of climate change in the urban context is needed to inform new planning solutions that consider local climate improvement as a performance indicator for a better quality of life.