Building a Climate-Resilient City: The built environment

Submitted by Christian Ledwell | published 20th Apr 2017 | last updated 13th May 2019
built-environment

Introduction

Climate change impacts involve threats and costs touching on all aspects of contemporary municipal life, and many of its effects on urban environments have yet to be effectively quantified. These growing climate risks have clear implications for local economies and the financial well-being of municipal governments. Well-planned adaptation measures can improve the quality of urban life as well as protect lives and infrastructure, strengthen community ties and improve economic performance.

The Building a Climate-Resilient City series was prepared for the City of Edmonton and the City of Calgary by the International Institute for Sustainable Development in collaboration with the University of Winnipeg’s Prairie Climate Centre. This series makes recommendations for steps that cities can take as part of their municipal adaptation planning to build their resilience to climate change. It explores three key principles of resilience building: robustness (strong design), redundancy (building extra capacity into systems to act as fail-safe networks) and resourcefulness (citizen empowerment).

This policy brief* looks at ways to build resilience in the built environment. Specifically, the paper explores climate-robust design options, effectively raising the bar in building design, and highlights some emerging Canadian best practices.

*The text below provides the key messages and recommendations from the brief and summarises some of the economic and financial factors that can support the building of climate-resilient cities. See the full text for much more detail.

Lessons Learnt

  • Buildings will be increasingly exposed to higher climate stresses and more frequent co-occurrences of climate shocks such as more variable and episodic snow loads and rain-on-snow episodes. New design tools such as the PIEVC protocol and the Climate Change Hazards Information Portal help developers and asset managers assess climate risk. Climate-smart design tools will provide a long-term strategic benefit to cities.
  • The built environment creates urban heat island (UHI) effects, which amplify heat waves and can be deadly to vulnerable elderly and infirm populations. UHI can be mitigated through spatial planning, including the strategic use of green and blue space. UHI impacts can also be mitigated by designating and maintaining cooling stations.
  • Architectural protocols such as LEED and district-planning paradigms such as EcoDistricts encourage patterns of resource use and community dynamics that increase resilience to the impacts of climate change.

Envisioning a Climate-Resilient Built Environment

The concept of the urban built environment can be extended to cover essentially all human-constructed infrastructure—residential, commercial and industrial buildings, as well as the water, energy, information and transportation networks that link them together. However, infrastructure networks are covered in other papers in this series. This paper focuses on buildings themselves and the spatial structure of the built environment—the contiguity and concentration of buildings in the urban context.

The urban built environment remains crucial in the broader battle against climate change. The built environment is exposed to the impacts of climate change for decades, given how slowly our capital stock of buildings turns over. We are now building the cityscapes of 2070, and approximately 80 per cent of the total environmental impact of the built environment is determined at the design stage. It is therefore essential that the decisions we make now in policy, planning and design increase climate resilience in the urban built environment. There are a variety of ways to contribute to building a more resilient built environment, some of which are illustrated through interventions that enhance the qualities of robustness, redundancy and resourcefulness:

  • Building Robustness: In Canada, the Public Infrastructure Engineering Vulnerability Committee (PIEVC) protocol advocated by Engineers Canada is an emerging norm for assessing climate impacts on buildings, the relative risks to specific building components and the appropriate design or retrofiting of adaptation measures. In addition to the PIEVC protocol, additional decision support systems are now commercially available to assess the climate risk exposure of buildings, including the Climate Change Hazards Information Portal (CCHIP). The fundamental constraint on the widespread application to these best-in-class design protocols and data resources is the political and institutional will to accept higher upfront costs to what current building codes require for both new construction and retrofits. 

  • Promoting Redundancy: Perhaps the most significant climate impact on and of the urban built environment is the urban heat island (UHI) effect. The UHI effect illustrates how redundancy attributes of climate resilience can be designed into the built environment. UHI is caused by the high thermal capacity (heat absorption) of dark-coloured materials in the built environment and essentially amplifies global warming. Mitigating UHI is primarily an urban spatial design issue and secondarily a building materials issue. Both urban sprawl and contiguous high-density urban development contribute to UHI; the ideal urban system appears to be a mosaic of high-density zones with interspersed green spaces and green belts to dissipate heat.

  • Encouraging Resourcefulness: Resourcefulness manifests first as a principle that the environmental impact and resource use within the built environment should be as low as possible. The most popular program for certifying the resource efficiency of buildings is the LEED (Leadership in Energy and Environmental Design) program developed by the non-pro t U.S. Green Building Council. A more demanding “resourcefulness in design” philosophy is the Living Building Challenge (LBC), which operationalizes the concept of the built environment as a tool for ecological and resource regeneration. The LEED/Living Building Challenge philosophy can be extrapolated to larger scales through the ecourban neighbourhood concept.

How Canada is and could be building robustness, promoting redundancy and encouraging resourcefulness in the built environment is discussed in much more detail in the brief. To read more about applying the above principles to the built environment in an urban context, please refer to the full text.

Recommendations

Strategic 

  • Define a climate-resilient built form as a strategic advantage for attracting investment and a comparative advantage.
  • Encode climate-resilient urban design as a distinct value proposition for your outwardfacing urban brand—for example, when working with site selectors for potential investment. The most resilient buildings or neighbourhoods will be the most competitive and will attract and retain capital and residents. The least resilient will suffer competitive disadvantages, capital outflows and expensive retrofits.
  • Conduct UHI analysis: identify “hotspots” and cross-reference with green/brown space inventory. Identify “greenable” and priority green spaces to maintain in pursuit of the optimal mosaic concept; integrate UHI mitigation as a strategic objective within neighbourhood revitalization plans. Consider deliberate planning and designation of the green spaces as (for example) cool green islands, and integrate xeriscaping and bioswale concepts for stormwater management (discussed in the water and sanitation paper in this series).
  • Conduct a multi-decadal urban ecosystem services analysis such as that recently conducted for the Metro Montreal region, including cooling services such as that provided by the tree canopy. 

Regulatory/Administrative 

  • Develop and encode regulatory and procurement standards (like PIEVC and CCHP) for climate-resilient design (retrofit and new build).
  • Consider dollar thresholds at which formal resilience and climate-risk management should be applied.
  • Increase administrative support for climate-resilient design by requiring Municipal Development Plans to benchmark climate resilience as incorporated in the EcoDistrict and 2030 District programs.
  • Require thermal (UHI) impact analysis of brown and greenfield development as a standard design consideration. Consider incentives for non-traditional building retrofits that ameliorate UHI, such as Toronto’s eco-incentives for green roofs.
  • Integrate UHI mitigation with naturalized stormwater retention features.

Economic Instruments

  • Incentivize climate-resilient built form through offsets, variances or planning assistance incentives to developers and consultations with insurance providers.
  • Reinforce existing instruments that encourage energy efficiency within the built environment at the residential scale. 

Voluntary/Community Linkages 

  • Develop workshops for asset managers, project developers on PIEVC protocols and other climate-risk management protocols such as CCHP. • Promote voluntary programs such as LEED and LBC to engage city planners, citizens and the design community in the implementation of individual buildings.
  • Similarly, voluntary programs such as EcoDistricts, One Planet Living and 2030 Districts engage stakeholders in broader district/neighbourhood planning initiatives. Vancouver has recently embraced both the Passive House program and the principles of the 2030 Districts with the intent to reduce greenhouse gases by 50 per cent by 2030 through incentives and offsets. These new frameworks can begin to change the stakeholder dialogue beyond minimum green building code regulations to resilient, net zero and regenerative frameworks required to make the transformation to a climate-resilient built environment.