People seem frequently to assume that the terms “sustainability” and “resilience” are synonyms, an impression reinforced by the frequent use of the term “climate resilience”, which seems to enmesh both concepts firmly.  In fact, while they frequently overlap, and indeed with good policy and planning reinforce one another, they are not the same.  This article picks them apart to understand where one ends and the other begins, and where the “sweet spot” lies in achieving mutual reinforcement to the benefit of disaster risk reduction (DRR).

Not the same…

A moment’s thought will bring to mind actions or infrastructure that may be environmentally sustainable but not resilient, and vice versa.  The wind turbines in Texas that (wrongly!) got the blame for last winter’s power outages there may be sustainable, but were clearly not very resilient, mainly because they had not been winterized.  Likewise, solar panels are liable to become projectiles in hurricanes unless they have been engineered to withstand the wind, as Puerto Ricans could confirm in the aftermath of Hurricane Maria.    Both the turbines and panels could have been protected – wind turbines are used north of the Arctic Circle, after all, and solar panels are used in hurricane prone locales across the Pacific – but at a cost of more energy for turbine gearbox heaters and more concrete and steel for panel anchorages.

Conversely, something could easily be resilient but not environmentally sustainable.  Engineered seawalls, as an example, will confer resilience to a shoreline, at least for a while, but often at a cost of interfering with sediment movement and build-up to the detriment of shoreline habitat and sometimes to the detriment of resilience further down the coastline.  Dams may control flooding, but often to the enormous detriment of ecosystems in and around the river.  Trees can help reduce urban heat island effects, but potentially at the expense of greater water withdrawals from the environment, in what are likely to be desert or drought-prone areas in the first place.

… but highly related.

For all the differences, though, sustainability and resilience clearly interact:  the UN’s Sustainable Development Goals (SDGs), for example, have resilience as a clear subtext to their focus on sustainability[1]. One way to think about the interaction is through a framework propounded by Prof Joseph Fiksel of The Ohio State University.   There is a continuum, of sorts, between the two poles of chronic stresses such as environmental degradation, and acute events (disasters).  Sustainability concerns the avoidance of accumulating chronic stresses, and resilience is the ability to rebound from acute events.  But interactions arise between different points on the spectrum.  Stresses such as deforestation may predispose a city to disasters such as flash floods or landslides; more generally, deforestation is a known driver of climate change and biodiversity loss, both of which have many resilience-reducing tendencies.

The picture gets more complex when other kinds of stresses – economic, social – are added in to the mix, because these play a role in the distribution of risk and are thus a factor in resilience.  As a general observation, disadvantaged communities often live in the most hazard-prone parts of town.  For example, in the San Francisco Bay Area, San Francisco’s affluent Marina district aside, many poorer and denser communities live on the “flatlands” beside the water which are more flood prone and exposed to the greatest seismic risk, and which also have the greatest numbers of non-code-compliant buildings.  Overseas, the same pattern is seen where lack of access to land encourages the growth of favelas or slums which may be exposed to flood or landslide risk.

Equally, however, social and economic stresses may hinder the ability of a city or community to recover from a disaster.  Poverty hinders the ability of communities to help themselves, as does a lack of social connectedness.  Disaster aid may be slow to arrive, unequally distributed or, in some countries, simply stolen.  Governance and economic stresses in New Orleans were major factors in its slow response to Hurricane Katrina.  Haiti, with its poverty and unstable governments, seems permanently unable to recover from its hurricanes and earthquakes before the next one strikes.

The sweet spot?

A complete approach to DRR, therefore, needs to address both sustainability, in all its dimensions, and resilience, and consider the interactions between them.  For this reason, the Ten Essentials for Making Cities Resilient, created to operationalize the UN’s Sendai Framework for DRR 2015-2030, explicitly include the protection of ecosystem services; less encouragingly, however, the Ten Essentials arguably do not adequately address social stress or inclusion issues.

The ideal situation has two parts.  The first would be to find actions that improve both sustainability and resilience.  Examples of actions that do this are diverse but include the following:

• Ecological forest management practices can significantly reduce risk of losses from wildfires, as experience with the still-burning Caldor and Dixie fires in California showed: those otherwise raging infernos left areas that had carried out earlier prescribed burns largely unaffected and with dramatically lower property losses. A recent report by the Nature Conservancy and Willis Towers Watson showed that such practices can make insurance feasible in areas where it was rapidly becoming impossible, and generate savings to fund the prescribed burns themselves.
• The approach pioneered in the Netherlands of “Room for the River” offers nature-based solutions to flood management, creating diverse habitats while also improving flood resilience.
• The work of the Institute for Diversity and Inclusion in Energy Management (IDIEM) has shown that addressing social stresses requires a conscious approach to diversity and inclusion in DRR – or quite simply, the disasters will be more profound and the losses will be greater.
• Work on resilience bonds has shown that they can alleviate the financial stresses that might otherwise prevent DRR activities.

The second part of the ideal would be a framework for managing the tradeoffs where sustainability and resilience do not align completely.  This will happen frequently – even with ecological forest management, for example, social resilience may be an issue: air quality managers often prevent prescribed burns out of fears for the damage that the smoke may do to people’s lungs.  Such a framework does not yet exist.   Although actuarial tools for valuing human lives and ecosystem services exist, their use is controversial and highly susceptible to being misunderstood.

Conclusion

Sustainability and resilience are not the same thing, but they are both overlapping and highly interactive with each other.  The cause of DRR (and the implementation of the UN’s SDGs) would benefit from a framework to help manage those interactions and the tradeoffs that may arise.

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[1] See also, as a detailed example page 15 of https://www.unescap.org/sites/default/d8files/knowledge-products/Toolkits%20final.pdf.