Just How Vulnerable are American States to Wildfires? A Livelihood
Vulnerability Assessment
Abstract
Wildland fires are becoming more destructive and costly in the United
States, posing increased environmental, social, and economic threats to
fire-prone regions. Quantifying current wildfire risk by considering a
wide range of multi-scale, and multi-disciplinary variables such as
socio-economic and biophysical indicators for resiliency and mitigation
measures, deems inherently challenging. To systematically examine
wildfire threats amongst humans and their physical and social
environment on multiple scales, a livelihood vulnerability index (LVI)
analysis can be employed. Therefore, we produce a framework needed to
compute the LVI for the top 14 American States that are most exposed to
wildfires, based on the 2019 Wildfire Risk report of the acreage size
burnt in 2018 and 2019: Arizona, California, Florida, Idaho, Montana,
Nevada, New Mexico, Oklahoma, Oregon, Utah, Washington, and Wyoming. The
LVI is computed for each State by first considering the State’s
exposure, sensitivity, and adaptive capacity to wildfire events (known
as the three contributing factors). These contributing factors are
determined by a set of indicator variables (vulnerability metrics) that
are categorized into corresponding major component groups. The framework
structure is then justified by performing a principal component analysis
(PCA) to ensure that each selected indicator variable corresponds to the
correct contributing factor. The LVI for each State is then calculated
based on a set of algorithms relating to our framework. LVI values rank
between 0 (low LVI) to 1 (high LVI). Our results indicate that Arizona
and New Mexico experience the greatest livelihood vulnerability, with an
LVI of 0.57 and 0.55, respectively. In contrast, California, Florida,
and Texas experience the least livelihood vulnerability to wildfires
(0.44, 0.35, 0.33 respectively). LVI is strongly weighted on its
contributing factors and is exemplified by the fact that even though
California has one of the highest exposures and sensitivity to
wildfires, it has very high adaptive capacity measures in place to
withstand its livelihood vulnerability. Thus, States with relatively
high wildfire exposure can exhibit relatively lower livelihood
vulnerability because of adaptive capacity measures in place. On the
other hand, States can exhibit a high LVI (such as Arizona) despite
having a low exposure, due to lower adaptive capacities in place. The
results from this study are critical to wildfire managers, government,
policymakers, and research scientists for identifying and providing
better resiliency and adaptation measures to support the American States
that are most vulnerable to wildfires.