Risky development

Risky development: Long-standing patterns drive increasing hazard exposure in the U.S.

Virginia Iglesias, Anna E. Braswell*, Maxwell B. Joseph, Caitlin McShane, Matthew W. Rossi, Megan Cattau**, Michael J. Koontz, Joe McGlinchy, R. Chelsea Nagy, Jennifer Balch, Stefan Leyk, and William R. Travis

Earth Lab, Cooperative Institute for Research in Environmental Sciences (CIRES) and Department of Geography, University of Colorado, Boulder, Colorado. *School of Forest Resources and Conservation, University of Florida, Gainesville, Florida. **Human‐Environment Systems, Boise State University, Boise, Idaho.

Presented at AGU Fall Meeting 2020

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We are losing more even as we know more

Damage from natural hazards is increasing despite the growing ability of the geo-sciences to delineate where and when extreme events will occur. We show that decades of risky development has increased exposure to the most damaging natural hazards.

AGU_2.mp3

Two geographies intersect

Exposure has grown in hazard hotspots since 1945

Drivers of increasing exposure vary with hazard

Expect worsening losses

The U.S. has for decades been on a risky and unsustainable development path that preferentially placed more property at risk of the most frequent and most intense natural hazards. A slowing of exposure growth in the last decade reflects the national pattern of slightly slower development, but hotspot growth still exceeds the national trend.
Exposure to natural hazards has escalated even in hotspots where development trends fall below the national values. For example, wildfire hotspots exhibit a 10-fold growth of the built-up area and 18-fold increase in structure density with respect to 1945.
Due to repetition of “build back bigger” after disasters, small gains in mitigation have been overwhelmed by larger trends that place more property value at risk. The “Harvey floods” and “Hurricane Katrina’s” of the future are poised to exceed $200b events.
Weather and climate hazards are worsening due to climate change, and though exposure growth shown here is driven by risky development, climate has already exacerbated loss trends and threatens to worsen losses from extant development.

Acknowledgements

Funding for this work was provided by Earth Lab through the University of Colorado Boulder’s Grand Challenge Initiative; NSF’s Humans, Disasters, and the Built Environment program (award #1924670 to CU Boulder); the Innovative Seed Grant program at CU Boulder, and the Eunice Kennedy Shriver National Institute of Child Health & Human Development of the National Institutes of Health (award # P2CHD066613). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. We gratefully acknowledge access to the Zillow Transaction and Assessment Dataset (ZTRAX) through a data use agreement between the University of Colorado Boulder and Zillow Group, Inc. More information on accessing the data can be found at http://www.zillow.com/ztrax. The results and opinions are those of the author(s) and do not reflect the position of Zillow Group. The authors would like to gratefully acknowledge Fathom Group.