Climate Change Resilience in Buildings: Leveraging IPCC AR6 for Risk Assessments

The impacts of climate change on buildings are becoming increasingly apparent as the frequency and intensity of extreme weather events escalate. To design resilient buildings, it is critical to incorporate the latest climate science into risk assessments and adaptation strategies. The IPCC AR6 Climate Change 2022: Impacts, Adaptation, and Vulnerability Report provides updated, robust insights into climate risks, far surpassing its predecessor, AR5.

This article explores how the building industry can use the findings from AR6 to meet Green Star’s Climate Resilience Credit and design for a Green Star Rated Buildings.

Why It Matters: Moving Beyond Compliance

Adopting AR6 for climate resilience assessments is more than meeting Green Star credits—it’s about safeguarding investments, lives, and ecosystems. Designing with AR6 ensures buildings are:

• Future-Proofed: Anticipate the realities of more severe climate scenarios.
• Sustainable: Resilient buildings reduce resource consumption and environmental impacts.
• Adaptable: Meet the needs of occupants and communities even during extreme events.

Green Star Buildings Climate Resilience Credit: An Overview

The Green Star Buildings Climate Resilience Credit is designed to ensure buildings are prepared to respond to the direct and indirect impacts of climate change. It encourages project teams to undertake comprehensive climate risk assessments and implement adaptation strategies that enhance the building’s resilience over its lifecycle. The credit has two achievement levels:

1. Minimum Expectation: Requires completion of a climate change pre-screening checklist that identifies and communicates the building’s exposure to climate risks. This checklist considers direct impacts (e.g., damage to building components) and indirect impacts (e.g., disruptions to dependent systems like power or transportation). Historic and future climate data must inform this analysis.
2. Credit Achievement (1 Point): Builds on the Minimum Expectation by requiring a detailed, project-specific Climate Change Risk and Adaptation Assessment, performed by a suitably qualified professional. This assessment must:
   • Use scenarios such as IPCC AR5 RCP 8.5 or the most recent equivalent (e.g., IPCC AR6 SSP-8.5).
   • Cover both medium-term (2040–2050) and long-term (2070–2090) timescales.
   • Address primary and secondary climate variables (e.g., temperature, flooding, bushfires).
   • Identify and treat all risks rated as “high” or “extreme” through design or operational strategies.
   • Ensure the results are communicated to all design leads for incorporation into the project.

Integration and Synergies

This credit synergizes with other Green Star credits such as Energy Use, Lifecycle Impacts, and Community Resilience, as well as Sustainable Development Goals like Goal 11 (Sustainable Cities and Communities) and Goal 13 (Climate Action). Additionally, it aligns with global reporting frameworks like GRESB and TCFD, ensuring projects meet broader sustainability and resilience benchmarks.

By undertaking this credit early in the design phase, project teams can maximize opportunities to integrate meaningful adaptation strategies, ensuring the building’s functionality, safety, and sustainability in the face of evolving climate risks. This proactive approach not only protects investments but also contributes to a more climate-resilient built environment.

Why IPCC AR6 Matters More Than AR5

The IPCC AR6 significantly refines and expands upon AR5’s predictions:

• Enhanced Precision: AR6 integrates 10 years of new data from advanced observational technologies and climate models, offering more precise regional predictions.
• Focus on Extremes: Unlike AR5, AR6 emphasizes that climate change impacts will be driven by the frequency and intensity of extreme weather events, rather than gradual shifts in climate averages.
• Cascading Risks: The report highlights interconnected risks (e.g., flooding leading to infrastructure failure), emphasizing the need for holistic resilience strategies.
• Warming Projections: Scenarios under AR6 project higher global warming levels:
  • RCP 4.5 (now SSP2-4.5) is likely to result in 3°C by 2100 (not 1.5°C as previously assumed).
  • RCP 8.5 (now SSP5-8.5) is projected to exceed 4.5°C, indicating dire risks without intervention (not 3°C as previously assumed in AR5).

Change in climate change scenario terminology from RCP to SSP

The shift from RCPs (Representative Concentration Pathways) in IPCC AR5 to SSPs (Shared Socio-economic Pathways) in IPCC AR6 reflects a significant evolution in climate scenario modeling.

RCPs primarily focused on radiative forcing levels (in Wm-2) by 2100, representing the physical trajectory of greenhouse gas concentrations, but they did not account for the socio-economic contexts driving emissions. SSPs, in contrast, integrate socio-economic narratives, such as population growth, economic development, and policy choices, to provide a more comprehensive view of how societal trends influence emissions and adaptation capacity.

While SSPs align broadly with RCPs in terms of radiative forcing, they tend to project higher concentrations for equivalent pathways (e.g., SSP5-8.5 compared to RCP8.5). This broader scope and increased granularity make SSPs a more nuanced tool for assessing both climate impacts and adaptation strategies. For climate risk assessments, transitioning to SSPs ensures alignment with the latest science and provides more contextually relevant insights for decision-making in the building industry. Updating terminology and scenarios to SSPs enables better-informed risk evaluations, particularly for extreme weather and cascading impacts emphasized in AR6.

For building projects, this means risk assessments must anticipate more severe scenarios and cascading impacts at the local and building scales.

Incorporating AR6 in Green Star Buildings Risk Assessments

Green Star Climate Resilience Credit

The Green Star Buildings tool includes a Climate Resilience Credit that encourages design teams to undertake comprehensive risk assessments. To align with AR6:

1. Update Risk Models:
   • Use Shared Socioeconomic Pathway 8.5 (SSP-8.5) scenarios for worst-case climate risk projections.
   • Analyze impacts like heatwaves, flooding, wildfires, and storm surges under these extreme scenarios.
2. Hire a Suitably Qualified Professional (SQP):
   • An SQP must conduct the assessment using IPCC AR6 data and methodologies.
   • Ensure the SQP considers cascading risks (e.g., how power outages from extreme temperatures might exacerbate indoor heat stress).
3. Climate Adaptation Reporting:
   • Undertake a likelihood and consequence risk matrix for identified climate risks and analyse impacts on building elements and systems.
   • Develop a detailed risk assessment report outlining identified risks, vulnerabilities, and proposed design adaptations.
   • Include actionable measures, such as raised foundations for flood-prone sites or enhanced ventilation systems for extreme heat events.

Designing for Resilience with AR6 Insights

1. Risk Analysis

• Use regional data from AR6 to identify specific hazards relevant to the building’s location.
• Evaluate risks across multiple dimensions:
  • Extreme weather: Frequency and intensity of heatwaves, storms, and floods.

2. Adaptation Strategies

Incorporate AR6-driven strategies into building designs:

• Adaptation: Adapt, defend, retreat. Analyse what design initiatives will allow this building to remain safe and intact for it’s predicted design life.
• Passive Design: Optimise building orientation, insulation, and materials to reduce energy demand during extreme heat or cold.
• Green Infrastructure: Use vegetative roofs, permeable pavements, and rain gardens to manage flood risks and improve microclimates.
• Robust Materials: Select materials resistant to increased wear from extreme weather (e.g., flood-resistant insulation, UV-stable finishes).

3. Continuous Improvement

• Regularly update risk assessments as new AR6 findings or local climate data become available.
• Use feedback loops from post-occupancy evaluations to refine future designs.

Why it’s important to update your climate risk analysis templates

The IPCC AR6 provides an essential framework for understanding and responding to climate risks at the building scale. By integrating these insights into Green Star risk assessments, design teams can lead the charge in creating climate-resilient infrastructure. As the impacts of climate change intensify, building for resilience is not just a choice—it’s a necessity.

For more information, explore the IPCC AR6 report here. Let’s work together to engineer buildings that not only withstand the future but thrive in it.

Implications for Building Design Risk Management

Summary of the Below Diagrams and the difference between Ar5 and AR6

The figure outlines global and sectoral climate risks associated with various warming scenarios, highlighting the increasing severity of impacts as temperatures rise relative to pre-industrial levels (1850–1900).

Key takeaways include:

1. Warming Projections (Panel a):
   • Under high-emission scenarios (e.g., SSP3-7.0 and SSP5-8.5), global temperatures are projected to exceed 3°C and 4.5°C, respectively, by 2100.
   • Lower-emission scenarios (e.g., SSP1-2.6) aim to limit warming below 2°C, but require significant global mitigation efforts.
2. Reasons for Concern (RFC) (Panel b):
   • Climate risks escalate with temperature increases, transitioning from moderate (yellow) to high (red) to very high (purple).
   • Categories include:
     • RFC1: Unique ecosystems (e.g., coral reefs, Arctic systems).
     • RFC2: Extreme weather events (e.g., heatwaves, heavy rains, wildfires).
     • RFC3: Disproportionate impacts on vulnerable populations.
     • RFC4: Global aggregate impacts, such as economic losses and biodiversity collapse.
     • RFC5: Irreversible events, such as ice sheet disintegration.
3. Sectoral Risks (Panels c and d):
   • Terrestrial and Freshwater Ecosystems (Panel c): Increased risks include biodiversity loss, tree mortality, and wildfire incidence at higher warming levels.
   • Ocean Ecosystems (Panel d): Significant damage to coral reefs, seagrass meadows, and kelp forests, exacerbating ecosystem degradation.
4. Human Health Risks (Panel e):
   • Projections show rising morbidity and mortality from heat-related illnesses, vector-borne diseases, and ozone-related mortality under limited or incomplete adaptation scenarios.
   • Proactive adaptation significantly reduces these risks.

Implications for Building Design Risk Management

1. Adopting AR6 Scenarios in Risk Assessments
   • Actionable Insight: Use high-emission scenarios like SSP5-8.5 for worst-case climate resilience planning.
   • Design Response: Consider cascading risks such as combined heatwaves and power outages or storms disrupting essential services.
2. Focus on Extreme Weather Events
   • Relevance: RFC2 highlights the disproportionate impact of extreme weather, which buildings must withstand.
   • Design Strategies:
     • Enhanced flood defenses and drainage systems.
     • Lifting services and electrical infrastructure well above flood levels.
     • Consider building on stilts or making lower floors out of flood and fire resilient materials.
     • Storm-resilient building envelopes. Consider increasing the wind ratings for structures and facades.
     • High-performance insulation to combat heatwaves.
3. Risk-Based Adaptation
   • Moderate to Very High Risks: RFC3 highlights the need to account for unevenly distributed impacts (e.g., urban heat islands affecting vulnerable populations).
   • Design Strategies:
     • Passive cooling for heat-sensitive areas.
     • Redundancy in critical infrastructure (e.g., power and water).
4. Health-Focused Building Design
   • Relevance: Climate-sensitive health risks (Panel e) emphasize the need for health-oriented adaptations.
   • Design Strategies:
     • Improved ventilation to address heat and air quality issues.
     • Safe indoor spaces for extreme weather shelters.
5. Ecosystem-Sensitive Development
   • Relevance: Panels c and d stress the importance of minimizing biodiversity loss and ecosystem degradation.
   • Design Strategies:
     • Green roofs and urban vegetation to mitigate heat islands and support biodiversity.
     • Building materials sourced from sustainable, low-carbon supply chains.
6. Planning for Irreversible Changes
   • Long-Term Perspective: RFC5 highlights risks from large-scale, irreversible climate impacts like ice sheet melting, which could lead to sea-level rise.
   • Design Strategies:
     • Avoiding development in flood-prone areas.
     • Designing for future sea-level rise.
7. Proactive Adaptation Investments
   • Value: Panel e demonstrates that proactive adaptation significantly reduces risks compared to limited or incomplete measures.
   • Recommendation: Incorporate climate resilience as a core investment during the design phase, rather than as an afterthought.

The IPCC AR6 highlights the urgency of integrating advanced climate risk assessments into building design. By adopting its insights, design teams can ensure that buildings are resilient, adaptable, and sustainable in the face of escalating climate risks. Proactive planning today will safeguard lives, ecosystems, and infrastructure in the decades to come.

In particular reference IPCC AR6 Climate Change 2022: Impacts, Adaptation and Vulnerability when undertaking risk assessments.

Reference:

IPCC AR6 Climate Change 2022: Impacts, Adaptation and Vulnerability when undertaking risk assessments. 

IPCC AR6 Climate Change 2022: Impacts, Adaptation and Vulnerability https://www.ipcc.ch/report/ar6/wg2/

Citation: Figure TS.4 in Pörtner, H.-O., D.C. Roberts, H. Adams, I. Adelekan, C. Adler, R. Adrian, P. Aldunce, E. Ali, R. Ara Begum, B. Bednar-Friedl, R. Bezner Kerr, R. Biesbroek, J. Birkmann, K. Bowen, M.A. Caretta, J. Carnicer, E. Castellanos, T.S. Cheong, W. Chow, G. Cissé, S. Clayton, A. Constable, S. Cooley, M.J. Costello, M. Craig, W. Cramer, R. Dawson, D. Dodman, J. Efitre, M. Garschagen, E.A. Gilmore, B. Glavovic, D. Gutzler, M. Haasnoot, S. Harper, T. Hasegawa, B. Hayward, J.A. Hicke, Y. Hirabayashi, C. Huang, K. Kalaba, W. Kiessling, A. Kitoh, R. Lasco, J. Lawrence, M.F. Lemos, R. Lempert, C. Lennard, D. Ley, T. Lissner, Q. Liu, E. Liwenga, S. Lluch-Cota, S. Löschke, S. Lucatello, Y. Luo, B. Mackey, K. Mintenbeck, A. Mirzabaev, V. Möller, M. Moncassim Vale, M.D. Morecroft, L. Mortsch, A. Mukherji, T. Mustonen, M. Mycoo, J. Nalau, M. New, A. Okem (South Africa), J.P. Ometto, B. O’Neill, R. Pandey, C. Parmesan, M. Pelling, P.F. Pinho, J. Pinnegar, E.S. Poloczanska, A. Prakash, B. Preston, M.-F. Racault, D. Reckien, A. Revi, S.K. Rose, E.L.F. Schipper, D.N. Schmidt, D. Schoeman, R. Shaw, N.P. Simpson, C. Singh, W. Solecki, L. Stringer, E. Totin, C.H. Trisos, Y. Trisurat, M. van Aalst, D. Viner, M. Wairu, R. Warren, P. Wester, D. Wrathall, and Z. Zaiton Ibrahim, 2022: Technical Summary. [H.-O. Pörtner, D.C. Roberts, E.S. Poloczanska, K. Mintenbeck, M. Tignor, A. Alegría, M. Craig, S. Langsdorf, S. Löschke, V. Möller, A. Okem (eds.)]. In: Climate Change 2022: Impacts, Adaptation, and Vulnerability. Contribution of Working Group II to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [H.-O. Pörtner, D.C. Roberts, M. Tignor, E.S. Poloczanska, K. Mintenbeck, A. Alegría, M. Craig, S. Langsdorf, S. Löschke, V. Möller, A. Okem, B. Rama (eds.)]. Cambridge University Press, Cambridge, UK and New York, NY, USA, pp. 37-118, doi:10.1017/9781009325844.002

Understanding Complex and Cascading Risks

In the context of climate change, complex risks refer to the interconnected and multi-dimensional challenges that arise when multiple climate hazards interact with vulnerabilities in socio-economic and environmental systems. These risks are difficult to predict and manage because they span across different sectors, regions, and systems. For example, extreme heatwaves can simultaneously strain power grids, disrupt water supplies, and impact human health, creating a web of interrelated impacts.

Cascading risks, on the other hand, occur when an initial climate-related event triggers a series of secondary and tertiary consequences, amplifying the overall impact. For instance, a flood caused by an extreme rainfall event can damage transportation infrastructure, disrupt supply chains, hinder emergency responses, and lead to prolonged economic and social disruptions.

AR6 emphasizes the significance of these risks because they are not isolated events; they compound and interact, making them more severe and challenging to address. For buildings, complex and cascading risks highlight the importance of moving beyond traditional risk assessments that focus on individual hazards, to more integrated approaches that consider system-wide vulnerabilities and interactions.

Incorporating Compound and Cascading Risks into Building Design Risk Analysis

To ensure resilience in the face of these risks, building design teams must adopt holistic risk analysis methods that account for the interconnected nature of climate impacts. Here’s how:

1. Systems Thinking Approach
   • Identify critical systems and their interdependencies (e.g., energy, water, transportation).
   • Evaluate how failures in one system (e.g., a power outage) could impact other systems (e.g., HVAC systems in buildings).
   Example: A hospital designed to be operational during a heatwave should include redundant power systems to ensure critical medical equipment functions even during grid failures caused by excessive energy demand.
2. Scenario Analysis
   • Use scenarios from the IPCC AR6, such as SSP5-8.5, to model extreme events and their cascading effects.
   • Simulate multi-hazard scenarios, such as simultaneous flooding and power outages, to assess building vulnerabilities under stress.
   Example: A coastal building might assess combined risks of storm surges (flooding) and extreme winds (structural damage), ensuring the design accounts for both hazards.
3. Spatial and Temporal Interactions
   • Assess how risks evolve over time and interact spatially.
   • For example, urban heat islands intensify heatwaves, increasing cooling demand while simultaneously stressing the local energy grid.
   Design Response: Incorporate passive cooling techniques, reflective materials, and micro-climate analysis to reduce dependency on grid-powered cooling systems.
4. Cascading Risk Mapping
   • Map out potential cascading impacts, starting from an initial hazard to identify secondary and tertiary effects.
   • Prioritize interventions that reduce vulnerabilities at each stage of the cascade.
   Example: If flooding damages transportation infrastructure, it may delay emergency repairs for buildings. Ensuring materials and backup systems are on-site could mitigate cascading delays.
5. Design for Flexibility and Redundancy
   • Flexible design allows buildings to adapt to changing risks. For instance, spaces designed for multiple uses can accommodate displaced residents or emergency shelters during climate events.
   • Redundant systems (e.g., dual water supplies or backup generators) reduce the likelihood of total failure.
   Example: A school could be designed with flood-resistant materials and adaptable spaces that double as community shelters during emergencies.
6. Engage Stakeholders
   • Collaborate with urban planners, utility providers, and emergency response teams to ensure building designs align with broader resilience strategies.
   • Share risk assessments with stakeholders to address vulnerabilities at the regional or city scale.

Conclusion on complex compound and cascading risks

Complex and cascading risks demand a shift in how buildings are designed, moving from single-hazard-focused assessments to integrated, system-wide analyses. By incorporating the latest findings from IPCC AR6 and adopting tools like cascading risk mapping and scenario modeling, design teams can create buildings that not only withstand climate extremes but also remain functional during multi-layered crises. This proactive approach ensures buildings contribute to community resilience and reduce vulnerability to future climate challenges.

Figure TS.10 COMPLEX RISK | Compound, cascading and transboundary impacts for humans and ecosystems result from exposure to the complex interactions of (1) multiple climatic hazards, including with non-climatic stressors , (2) multiple vulnerabilities compounding the effect of risks, and (3) multiple impacts/risks that compound and cascade to spread across sectors and boundaries.

Source: IPCC AR6 Climate Change 2022: Impacts, Adaptation and Vulnerability https://www.ipcc.ch/report/ar6/wg2/

Citation: Figure TS.10 COMPLEX RISK in Pörtner, H.-O., D.C. Roberts, H. Adams, I. Adelekan, C. Adler, R. Adrian, P. Aldunce, E. Ali, R. Ara Begum, B. Bednar-Friedl, R. Bezner Kerr, R. Biesbroek, J. Birkmann, K. Bowen, M.A. Caretta, J. Carnicer, E. Castellanos, T.S. Cheong, W. Chow, G. Cissé, S. Clayton, A. Constable, S. Cooley, M.J. Costello, M. Craig, W. Cramer, R. Dawson, D. Dodman, J. Efitre, M. Garschagen, E.A. Gilmore, B. Glavovic, D. Gutzler, M. Haasnoot, S. Harper, T. Hasegawa, B. Hayward, J.A. Hicke, Y. Hirabayashi, C. Huang, K. Kalaba, W. Kiessling, A. Kitoh, R. Lasco, J. Lawrence, M.F. Lemos, R. Lempert, C. Lennard, D. Ley, T. Lissner, Q. Liu, E. Liwenga, S. Lluch-Cota, S. Löschke, S. Lucatello, Y. Luo, B. Mackey, K. Mintenbeck, A. Mirzabaev, V. Möller, M. Moncassim Vale, M.D. Morecroft, L. Mortsch, A. Mukherji, T. Mustonen, M. Mycoo, J. Nalau, M. New, A. Okem (South Africa), J.P. Ometto, B. O’Neill, R. Pandey, C. Parmesan, M. Pelling, P.F. Pinho, J. Pinnegar, E.S. Poloczanska, A. Prakash, B. Preston, M.-F. Racault, D. Reckien, A. Revi, S.K. Rose, E.L.F. Schipper, D.N. Schmidt, D. Schoeman, R. Shaw, N.P. Simpson, C. Singh, W. Solecki, L. Stringer, E. Totin, C.H. Trisos, Y. Trisurat, M. van Aalst, D. Viner, M. Wairu, R. Warren, P. Wester, D. Wrathall, and Z. Zaiton Ibrahim, 2022: Technical Summary. [H.-O. Pörtner, D.C. Roberts, E.S. Poloczanska, K. Mintenbeck, M. Tignor, A. Alegría, M. Craig, S. Langsdorf, S. Löschke, V. Möller, A. Okem (eds.)]. In: Climate Change 2022: Impacts, Adaptation, and Vulnerability. Contribution of Working Group II to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [H.-O. Pörtner, D.C. Roberts, M. Tignor, E.S. Poloczanska, K. Mintenbeck, A. Alegría, M. Craig, S. Langsdorf, S. Löschke, V. Möller, A. Okem, B. Rama (eds.)]. Cambridge University Press, Cambridge, UK and New York, NY, USA, pp. 37-118, doi:10.1017/9781009325844.002.