By Marisa Henry
[TL;DR] In the aftermath of Hurricane Harvey flooding Houston, Texas, many have turned to social media and traditional news media to debate the role of climate change, urban sprawl, and lax zoning laws on the storm's impacts. This post focuses on how we can encourage Houstonians to take the necessary steps to prepare for future storms by acknowledging behavioral biases. It addresses challenges in risk communication and the flood insurance market and calls for stronger policy action in the wake of natural disasters.
Note: This post will not try to argue the existence of anthropogenic climate change or its role in recent storms like Harvey. Further, it will not discuss the specific role of sprawl and rapid urbanization on flooding. You can find many other new posts and articles on these issues if you're interested. I would recommend the ProPublica series on Houston from 2016, for starters.
In late August, Hurricane Harvey caused disastrous flooding in Houston, Texas and surrounding areas. As the storm subsided and damage was assessed, the media swiftly began to debate the contributing causes of the disaster.
Climate change-related warmer sea surface temperatures in the Gulf of Mexico contributed to storm's intensity. Houston's rapid urbanization and extensive urban sprawl have replaced water-absorbing wetlands with vast spaces of concrete. Further, the city's relatively lax zoning laws and building codes have contributed to cheap development flourishing far beyond what could be considered sustainable.
In the media hype, it's easy to argue what should or shouldn't have been done in the past to prevent damage. However, it's more challenging to spin these criticisms into positive steps forward. It's even more demanding to expect individuals who have been intimately affected by Harvey to take action when they are focused on getting their lives back to normal.
Given that another "unprecedented" flood could be just around the corner for Houston, what can we do to ensure Houstonians take the necessary steps to prepare for future floods?
How do we rebuild in a way that addresses behavioral biases and is more empathetic to individuals who have suffered loss from natural disasters?
Communicate Risk More Clearly
I grew up in the suburbs of Houston and have experienced many heavy summer rains and a number of powerful hurricanes, including Ike in 2008, which knocked out the power in my neighborhood for over a week. Heavy rains and flooding streets are nothing too unusual for Houstonians: Houston is in a low-lying, coastal area, where floods have been happening for as long as records are available.
But the scale of repeated flooding events in recent years has become exasperating. Houston has experienced three "unprecedented" floods in the past three years: the so-called Memorial Day Floods of 2015, the Tax Day Floods in 2016, and most recently the floods caused by Harvey.
Behavioral biases and a miscommunication of the risk and uncertainty associated with storm predictions make the repeated flooding events of recent years seem highly unusual, when in reality the probability of another intense storm occurring next year hasn't changed.
When a storm is deemed a "one in 100 year event", this means scientists estimate there is a 1 percent chance of this magnitude of storm occurring each year. This is not the same as suggesting that a storm of this magnitude will only happen once every 100 years (as the name seems to suggest). It describes a probability, not specific timing. So when there's a "one in 100 year storm event" in 2015, people tend to think such an event won't happen again for another 100 years, which is not what is meant by the terminology.
Additionally, there are relatively large uncertainty bounds around these estimates that are not properly communicated. The storm classifications are based on historical data, which does not reflect current climate patterns or levels of development that influence storm strength and flooding impacts. Further, when you get to a 1 in 100 year storm or anything more extreme than that (e.g. a 1 in 500 year storm), the uncertainty bounds grow since we do not have sufficient historical data to more accurately predict these probabilities.
This risk and uncertainty must be communicated more clearly if we expect more rational decision making in the process of rebuilding.
However, even if these risks and uncertainties are communicated and understood correctly, people also have behavioral biases of "overconfidence in good fortune" that keep them from reacting appropriately to their level of true risk. Programs and policies should aim to address these biases beyond just providing better information.
Change the Incentives for Flood Insurance
Despite repeated flooding events in recent years, only around 15 percent of the city has flood insurance. Part of this low uptake may be from poor communication about the risks of storm events to the public. It is also difficult to encourage insurance adoption as homeowners without insurance are able to apply for disaster grants for rebuilding after natural disasters like Harvey, which disincentives flood insurance.
The low adoption of flood insurance nationally also places the NFIP in trouble financially. After a storm like Harvey, the NFIP has to offer large payouts to many households, requiring them to borrow from the U.S. Treasury. If the NFIP was a private company, it would be bankrupt.
There is a need to shift the incentives of flood insurance to increase its adoption. Policies should also ensure homeowners are paying rates that more accurately reflect their flooding risk to enable the continued functioning of the NFIP.
A need for stronger policies
In the wake of such disasters, most of us feel empathy for those impacted. Hashtags like #PrayForHouston trend and aid funds grow, but:
"what’s likely to happen is we’re going to spend tens of billions of dollars rebuilding Houston exactly like it is now, and then wait for the next one,” said Rob Moore, a senior policy analyst on water issues for the Natural Resources Defense Council.
Although this is politically the easiest short term solution, it is clearly not a very robust long term strategy for dealing with natural disasters. This drive to rebuild as fast as possible must be complemented by an increased policy focus on restructuring and redeveloping cities to better withstand future storms.
In addition to the better risk communication and flood insurance incentives mentioned above, this could include: investments in green infrastructure, changing building codes in flood-prone areas, and greater protection of remaining wetlands in the area.
It’s not just Houston
Just a couple of weeks after the floods from Harvey, Hurricane Irma slammed the Caribbean and Florida, and then Hurricane Maria further devastated Puerto Rico and the Caribbean. The 2017 Atlantic hurricane season has been more intense than the average year (and it's not over until November). Further, there have been disastrous floods in India, Bangladesh, Nepal, Nigeria, and Sierra Leone since August 2017.
These storms and other natural disasters are happening globally and those in less developed areas are arguably less equipped to deal with the aftermath, relative to a city like Houston. Even the responses to the most recent disasters in Houston and Puerto Rico (a U.S. territory) have received significantly different levels of attention and aid.
Although the specific strategies taken to address rebuilding will vary between locations based on the local context, available resources, and institutions, we must aim to develop appropriate sustainable development/redevelopment programs to avoid (or at least minimize) an increase in the suffering of humankind to these kinds of disasters globally.