Feeling vulnerable? Maybe you’re just exposed.
Exposure, vulnerability, and risk are different concepts. Let’s talk vocabulary.
Last month I attended the 2019 National Adaptation Forum in beautiful Madison, Wisconsin. The NAF, as it’s known in the field, is a biannual meeting of the adaptation community focused on moving beyond adaptation awareness and planning to adaptation action. It’s been convened by EcoAdapt, the Seattle-based adaptation non-profit, since 2013.
I did a lot of networking, saw a lot of presentations, and learned about a lot of things during the NAF this year—including that fact that those of us in the adaptation field aren’t all using the same language. That’s not good.
Let’s talk vulnerability. (The definition below, like those that follow, is from the U.S. Climate Resilience Toolkit.)
Vulnerability: The propensity or predisposition of assets to be adversely affected by hazards.
Vulnerability encompasses exposure, sensitivity, potential impacts, and adaptive capacity. (All of those terms are also defined in the CRT, which you can easily find in the site’s handy-dandy glossary.) Vulnerability encompasses exposure, but they’re not the same thing.
Exposure: The presence of people, assets, and ecosystems in places where they could be adversely affected by hazards.
In other words, an asset (a building, an ecosystem, a person) can be EXPOSED to a climate hazard (a flood, a wildfire, a heat wave)—but that doesn’t mean that it’s VULNERABLE to that climate hazard. To make that determination, you also have to consider other things, such as the asset’s sensitivity and adaptive capacity as well as potential impacts. Briefly:
- Sensitivity has to be considered because assets vary in how they’re affected by climate hazards. For instance, the yield of crops with a high sensitivity might be reduced in response to a change in daily minimum temperature during the pollination season. Other crops—those with low sensitivity—may not be affected by such a temperature change at all.
- Adaptive capacity has to be considered because assets vary in their ability to cope with change. Increasing the diameter of culverts that channel stormwater away from assets, for example, enhances the adaptive capacity of places that face flooding from increasingly heavy rainfalls. Neighborhoods that house lower income populations, which probably don’t have the financial resources to tackle climate adaptation on their own, may have a lower adaptive capacity than that of an affluent neighborhood.
- Potential impacts have to be considered because assets vary in how they’re affected by a hazard. In some cases, a climate hazard can even be beneficial to an asset. Wildfire, for example, can be beneficial for ecosystems—it reduces hazardous fuels, protecting human communities from extreme fires; minimizes the spread of pest insects and disease; removes unwanted invasive species; provides forage; improves habitat for threatened and endangered species; recycles nutrients back to the soil; and promotes the growth of trees, wildflowers, and other plants.
So the bottom line is that exposure does NOT equal vulnerability. They’re two different concepts.
What I saw at NAF, though, was the confounding of exposure as vulnerability…or, worse yet, risk.
Risk: The potential total cost if something of value is damaged or lost, considered together with the likelihood of that loss occurring.
Risk is often evaluated as the probability of a hazard occurring multiplied by the consequence that would result if it did happen. Warehouses sited on a floodplain represent a higher risk for flooding when they are filled with products than when they are empty. That’s an entirely different concept.
Loading a residential properties layer on map and overlaying it with a 100-year flood layer is not a vulnerability analysis—it’s an exposure analysis. Identifying vulnerable populations with the CDC’s Social Vulnerability Index and overlaying that with a projected extreme heat layer is not a vulnerability analysis—it’s an exposure analysis. Creating an asset-hazard pair, any asset-hazard pair, and seeing where they may intersect is not a risk analysis—it’s an exposure analysis.
We’re obviously not all on the same page, and we should be. A shared framework and vocabulary will help the community develop standard measures, link websites, compare projects, and build a more cohesive Resilience Ecosystem.
What do you think? Leave me a comment below, or—even better—take this survey to provide feedback to the CRT’s editorial team:
