Protecting Against Climate Change’s Mega-Storms

 

On August 24, 2017 hurricane Harvey made landfall in Texas as a category 4 hurricane. It was the first major hurricane to hit Texas since 1970 (Allen & Davis, 2017), and it was devastating. The storm delivered a year’s worth of rain in less than a week, being called the wettest tropical storm on record in the United States as affected areas received more than 40 inches of rainfall with peak accumulations of 64.58 inches in just four days (Dart & Helmore, 2017, para 3). The two main flood-control reservoirs that were supposed to protect the Houston area broke. Water levels rose dramatically, damage was increased tenfold, and hundreds of lives were lost. A storm surge of over 12 ft was reported at Aransas Wildlife Refuge, and other areas had storm surges ranging from 3-10 ft as the hurricane stalled over southeast Texas. Hurricane Harvey is the costliest hurricane to ever hit the United States, the damage is so high that it was feared that Texas will not receive enough money to rebuild within a month. Eventually congress budgeted 7.8 billion dollars for recovery efforts, which was only a small fraction of what was truly needed out of the $180 billion that Harvey cost (McWilliams & Parraga, 2017, para 5). After the hurricane, relief efforts were not only attempted by agencies and different government organizations, but also by neighbors and friends. With a disaster as devastating as Harvey, people needed each other to come together and offer relief and support.

It is apparent that climate change is altering the world around us and that hurricanes are becoming more severe as a result. Global warming is changing our oceans, causing a rise in sea surface temperatures, and sea levels, which creates more favorable conditions for intense hurricanes (Mallard, Lackmann, Aiyyer, & Hill, 2013). Hurricanes are classified by the amount of damage they inflict, which is based off of wind speeds and duration of the storm. A category 5 storm is the most severe and a category 1 storm is the least severe. (National Oceanic and Atmospheric Association [NOAA], 2017). Since it is easier for severe hurricanes to form, there has been a global decline in weaker hurricanes with a proportional increase in higher category storms by 2-11% (Holland & Bruyère, 2014, p. 623). We are already seeing the aftermath of such implications; severe hurricanes, which are often classified as a category 3, 4, or 5, cause significantly more damage as opposed to a category 1 or 2 hurricane (Abrams, 2017). A major cause of damage and life loss are the incredible storm surges that large hurricanes cause (NOAA, 2011). High storm surges have been reported in nearly all the hurricanes this past season, including Hurricane Irma, Hurricane Maria, and Hurricane Harvey (“Hurricane Irma”, 2017; “Major Hurricane Harvey”, 2017). Results of these hurricanes have included major flooding and infrastructural damage in affected areas, in many cases overwhelming hurricane defenses already in place (“Hurricane Katrina”, 2009). Hurricane Irma, which recently swept through Florida and the Caribbean, was the first category 5 hurricane to strike the Leeward Islands of Puerto Rico, and is said to be the most intense hurricane to hit the United States since Hurricane Katrina (“Hurricane Irma”, 2017). Just two weeks later hurricane Maria, the tenth most intense hurricane on record swept through Puerto Rico and the Dominican Republic causing catastrophic damage and sending Puerto Rico into a state of emergency (NOAA, 2017). During this past hurricane season, there have been eight big hurricanes which is double the yearly average (Rice, 2017, para 4). Three category 4 and 5 hurricanes have hit the United States in 2017, inflicting severe flooding, which is a first in hurricane history. This trend of bigger, more damaging hurricanes can not be ignored. The current barriers in place are no longer a reliable defence against the greater intensity of these storms.      

Despite the evidence, climate science is still disputed and claims no connection between climate change or its effect on sea surface temperature that ultimately affects hurricane intensity. Nevertheless, the scientific community has reached consensus and agrees that the planet is warming due to climate change (Wang et al., 2016), and that it is affecting storm strength. For each degree Celsius of global warming, there is an 11% increase in the proportion of category 4 and 5 hurricanes, but a 7% decrease in hurricanes that are category 1 and 2 (Holland & Bruye?re, 2014, p. 623). Warming sea surface temperatures have lead to more intense and violent hurricanes with larger storm surges (Kieper, n.d.) causing more and more damage each year to coastal communities in the United States (Dinan, 2017).

Natural disasters such as these are ultimately unavoidable, and there are many people who work to try to predict them in order to protect people from the damage. Anticipating hurricanes and their severity are paramount for providing effective damage and flood protection. Our effect on the climate through anthropogenic climate change has lead to an increase in hurricane intensity causing hurricanes to become bigger and last longer. Our knowledge of how global warming is affecting hurricanes can allow us to prepare more for these storms. The increase of severe, higher category storms will cause more damage than the milder hurricanes we are more accustomed to. As hurricanes intensify, there are greater costs to our economy, infrastructure, and lives (Wang, Li, Zhang, & Ellingwood, 2016; Mallard et al., 2013). There are two major types of damage caused by hurricanes: water damage and wind damage. Wind damage is caused by the high speed winds in a hurricane that can exceed 150 miles per hour which can rip trees out of the ground and move buildings (NOAA, 2017). Water damage is caused by the rain and storm surge associated with the hurricane. Flooding from these events can ruin homes, roads, coastal habitat, and even end lives. Infrastructure that was once used to hold back this storm surge is failing more often as they are overwhelmed by intense storms (Lafrance, 2015). While flood barriers won’t be able to protect communities and the landscape from wind damage, reducing the amount of water damage that will occuring during a hurricane will give people more time to protect themselves against wind damage and reduce the costs of recovering after a hurricane. For example, out of Hurricane Harvey’s 180 billion dollar bill, only 2 billion dollars of the damage was caused by wind (Wattles, 2017, para 9). It is imperative that better flood control and protection be improved and implicated to protect the people and land from severe flooding.    

As seen during hurricane Harvey, the precautions and systems in place are not enough to safely mitigate a storm. Steps that are taken in preparation include: hurricane, tropical storm, and storm surge watches, evacuation, sandbags, rescue cars and boats in case of flooding, and checks of the city’s drainage system (National Hurricane Center [NHC], 2017). No matter the preparation Hurricane Harvey breached levees and flowed over dams. In order to protect ourselves during future hurricanes and their storm surge, flood barriers, a form of levee, should be built along high risk coastlines or inlets. Areas that are at risk are cities built along the coast, which are often densely populated and at least partially below sea level. Cities that fit this criteria are Miami, Florida; New York City, New York; Tampa, Florida; and Virginia Beach, Virginia (Glink, 2013). A flood barrier is a fixed flood gate system that allows water to pass during normal conditions, but in the event of a storm or high water level, the gates are closed which stops water from passing and prevents flooding (European Climate Adaptation Program [ADAPT], 2015). These are improvements on traditional levees, which are typically artificial embankments. These structures are often placed at the mouths of inlets, rivers, or partially along certain low lying coastlines. They work by permanently installing either two gates at either side of an area, or a row of panels underneath the water. In the event of dangerous flooding, the gates swing closed through the water, creating a seal to prevent more water from entering. Or, the panels beneath the water rise, creating a wall against flood water. Flood barriers have been built in several cities throughout the world that are in high danger of flooding.

Other areas have already taken the initiative to bolster their protection against flooding. The Netherlands for example is an extremely prone country to storm surge flooding, since half the country is just one meter above sea level and more than an eighth is below sea level (Kimmelman, 2017). In 1997, the Netherlands built Maeslantkering, a storm surge barrier protecting the city of Rotterdam. At 1,600 ft long, the barrier is a modern engineering triumph capable of protecting Holland from the storm surge and rising sea levels it is so susceptible to (“Maeslantkering”, 2017; Kimmelman, 2017). The Netherlands isn’t the only country to implement this type of technology. Italy completed the Venice Mose Barriers in 2012, which also protects the low lying city from floods and sea level rise. Both countries are at risk of storm surges and have histories of major flooding, and the barriers are effective.

Levees are typically built to withstand a hundred-year flood event, which is an exceptional flood that has about a 1% chance of occurring each year. When a system is built to withstand a hundred year event, it assumes that the event will not change or get worse in that time period (United States Geological Survey [USGS], 2016). This is particularly problematic with global warming, since global warming has been rapidly changes the types of storms we experience, often making them much more severe. Therefore a hundred-year levee can easily become overwhelmed when storms that are more intense and more frequent than it was built for occur, making it essential that we build levees to more long term standards. The Netherland’s flood barrier is built to withstand a 10,000-year flood event. This makes it 100 times safer than the standards set for levees in the United States. Furthermore, since is it is built to last much longer, the Netherlands mandates that the flood control system must be upgraded accordingly to changes in frequency and intensity of flood events, so that the protection stays the same if the threat changes (McQuaid, 2012, para 8). While nothing can stop a hurricane or completely protect against them, more effective and technologically advanced systems can dramatically reduce their impact.

Upgrading our levees and flood barriers are not a foreign idea to the United States. The Army Corps of Engineers is responsible for various homeland duties such as environmental engineering, coastal fortifications, road and canal infrastructure, and disaster relief. With the Army Corps of Engineers’ generous budget and responsibility to preserving our homeland defenses against various threats, including natural ones, the U.S can fund and build select flood barriers, which has been demonstrated in Louisiana after hurricane Katrina in 2005. Hurricane Katrina created the highest storm surge in the U.S’s recorded history at 27.8 ft high (Kieper, n.d., Para 1). New Orleans, the city most devastated by the hurricane, is well below sea level. Before Katrina, it was protected from flooding only by a handful of rundown dams and levees. During the hurricane, all of these systems failed to be enough and residents had fled to rooftops to escape the water as 80% of the city became submerged. Relief was painfully slow, as the hurricane caused over $150 billion in damage and economic costs (“Hurricane Katrina”, 2009; “11 Facts About Hurricane Katrina”, n.d., para 7&8). To fortify the city against such a devastating effect again, the Army Corps of Engineers has built a flood barrier around New Orleans, which should have been in place before Katrina (Burnett, 2015). This individual flood barrier cost approximately $1.1 billion to build; while this may seem like an astronomical number, it is dwarfed by the $150 billion that the storm generated. The Louisiana coast is considered to be much safer with the flood barrier, which is considered a state entity to consolidate and provide better flood control after the hurricane (Burnett, 2015, para 4).

Some may be skeptical of the cost of investment in flood barriers as these systems are expensive and take years to complete. Furthermore, even with our current technology, we cannot guarantee complete safety. Flood protection systems have failed in the past raising questions about our ability to protect our coastal communities, and this concern comes with good reason. When Katrina made landfall in August 2005 as a category 5 hurricane, New Orleans’ levee system, which was designed by the United States Army Corps of Engineers, failed due to high wind speeds, heavy rain, and high storm surge. The city, where 50% of its residents lives below sea level, flooded taking 1,500 lives and causing $108 billion worth of property damage alone (“Hurricane Katrina Statistics Fast Facts”, 2017, para 1). However, advancement in hurricane forecasting has improved our ability to predict future storm intensity. Using this technology the United states Army Corps of Engineers have rewrote the standards used for flood barriers better preparing us for more severe storms and invested a total of $14 billion into improving and the levees and building new barriers to protect New Orleans (Burnett, 2017, para 5). Although, even with the rework of levee standards, retired Lt. General Robert Van Antwerp, the former commander of the Army Corps of Engineers said “though it would not be destroyed by another Katrina, it would most certainly be overtopped leading to many that will still be inundated” (Schleifstein, 2015, para 7). Divesting money from coastal protection should not be an option as the money is an investment in limited damages and is not intended to make our communities completely safe.
In 2015 the corps agreed that Louisiana’s levee system needed to be reevaluated by 2018. This occurred after Bob Jacobsen, who was hired to run storm surge models, found that many levees in the east bank system would fail if a 200 year storm hit, which has a .2% chance of happening in any given year. Over the next 50 years there will be $50 billion worth of projects improving New Orleans levees with risk reduction and land protection as the goal. The corps have proposed both 400 year and 1,000 year protection plans both costing $59 billion to $139 billion (Schleifstein, 2015, para 32). The corps argue that if we are going to spend the money to protect against a 100 year storm, we might as well go for the most protection possible.

Upgrades to our current flood protection systems will not be enough to protect our coastal communities. It would be most beneficial to build new flood barriers around the cities most in danger from hurricanes. An example of where there could be implemented is New York City, where flood barriers have been considered following Hurricane Sandy in 2012 (McGeehan, 2017). Hurricane Sandy caused widespread power outages, took dozens of lives, and caused billions of dollars in damage (Sharp, 2012). If a simple flood barrier were to be built protecting New York City, it would cost about $11.6 billion, and if three barriers were built along New York coast, the estimated cost is $14.7 billion (Timmer, 2014, para 8). These are costly options, yet Hurricane Sandy caused $65 billion in damage to New York (Rice & Dastagir, 2013, para 2). No matter the price tag on a flood barrier, severe hurricanes rack up a larger one. With the success of barriers in other countries and in New Orleans, barriers are a solution to protect ourselves against dangerous storms as climate change cause worse and worse hurricane events.

This past hurricane season has been swirling through the United States at unprecedented rates. The eight major hurricanes that made landfall along our coasts is double the normal average for the hurricane season (Rice, 2017). Hurricanes are being affected by rising sea surface temperatures, due to global warming. In turn, hurricanes are more intense, occurring more often. This has created a vital need for a more secure defense system against hurricanes and storm surges. In Louisiana and New York, it is agreed that adequate flood barriers would have reduced cost and life loss due to the hurricanes. If better flood barriers were to be built, then the cost could be estimated to be about $12 billion per city, referencing the costs approximated for New York. If we were to build around three cities with the highest risk, then it likely cost $36 billion. While that is a large cost, hurricane Harvey was dramatically larger at $180 billion. Building three barriers does not even equate the cost of a singular hurricane. Providing at risk areas with more effective protection against hurricanes will be undoubtedly beneficial, economically and personally. The damages that hurricanes inflict are far greater than the simple price of building and maintaining effective barriers. The lives, and money, saved are more than enough reason to build flood barriers around dangerous coastal areas.  

AUTHORS

Jennifer Beattie – Natural Resource Conservation

Juliana Berube – Natural Resource Conservation

Tyler Weeks – Building Construction Technology

 

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Evan