1. Introduction

The scale and nature of climate change issues require a much more rapid and radical change built environments ^{[1][2][3][4][5]}. Existing and new built environments need to be have characteristics that enable sustainability such as increased densities, mixed-use neighbourhoods, renewable energy systems and products and services based on the circular economy.

Climate change also means that built environments must adapt to new and unpredictable weather conditions including extreme heat, storms and flooding^{[6][7][8][9][10]}. This will require characteristics which support resilience such as increased insulation and cooling systems, strengthened structures, and raised floors and flood walls. 

2. Conflicts between Resilience and Sustainability

These pressures raise several questions. Can more built environments be created which are both more sustainable and more resilient? In developing more sustainable environments, can resilience principles be drawn on to address climate change? How can the apparent conflicts between these approaches be managed? 

3. Resilient Sustainability

Achieving sustainable development and climate change targets will require the integration of sustainability and resilience. This integration can be referred to as resilient sustainable. Resilient sustainability is described by López-Ridaura et al., in the following way:

“..the degree to which a system is sustainable will depend on its capabilities to produce…, a specific combination of goods and services that satisfies a set of goals ..even when facing..‘extreme’ …variations” ^[11].

Thus, in built environments,  resilient sustainability can be understood as the development of built environments which enable sustainability, while ensuring that the functionality of these environments is maintained and enhanced through a focus on resilience

Resilience in urban and built environments has been addressed by the City Resilience Index developed by Arup, the City Resilience Profiling Tool developed by UN-Habitat and disaster resilience indicators developed by ISO as well as cities^{[12][13][14][15][16]}.

These frameworks focus on the recovery and adaptation of existing engineering and ecological systems^[17]. They do not include transformation and social change ^[18] . Resilience frameworks are also selected for their ability to reinforce and strengthen particular sectors ^[19]. Thus, for instance, some frameworks will address flooding, while others will deal with issues such as the COVID-19 pandemic ^[17].  The RESUME framework focuses on achieving resilient sustainable development. 

4. Resilient Sustainability Measurement and Evaluation (RESUME) Framework

The Resilient Sustainability Measurement and Evaluation (RESUME) framework aims to ensure that sustainable development trajectories are maintained. It combines sustainability objectives and resilience principles to propose resilient sustainable built environment capabilities and characteristics^[20]. These are shown in the table below.

5. Discussion

The RESUME tool includes criteria that measure these resilient sustainable built environment capabilities and characteristics and can be used to evaluate urban areas and has been used to assess informal settlements in South Africa.

The RESUME approach differs from other urban resilience frameworks in two distinct ways.

First, instead of a broad focus on the recovery of engineering and ecological systems, it aims to develop and maintain more sustainable systems. Thus, if climate change damaged an unsustainable system, its recovery in its current form would not be prioritized and instead, a more sustainable adapation or a replacement with a more sustainable system would be prioritised.

Second, change and transformation are integral to the methodology. Rather than reinforcing the status quo, it seeks to promote change and transformation that create more sustainable resilient systems. 

6. Conclusion

By combining sustainability and resilience, the concept of resilient sustainability and the RESUME methodology provides a way to address sustainability and resilience simultaneously. Efficiencies generated by this synthesis approach are very valuable given the nature and scale of climate change and sustainable development challenges and the limited resources available to address this. 

7. Acknowledgements

This paper draws on a paper by Gibberd which develops the concept of resilient sustainability and applies it through the RESUME framework to assess neighbourhoods^[20].