Human Influence Apparent as Houston Staggers Under Hurricane Harvey
Analysis & Special Reports
Rain continued to pummel the Houston area Tuesday, as the full extent of the damage caused by hurricane-turned-tropical storm Harvey continued to be tallied, and the search began for attribution—both for the storm’s fury, and the inadequacy of the infrastructure in America’s fourth-largest city to cope with more than four feet (1.2 metres) of water falling over several days.
On Tuesday evening, the Washington Post put Harvey’s impact at 22 dead, with 25 to 30% of Harris County flooded and upstream reservoirs overflowing. CNN reported 10,000 evacuees housed at Houston’s George Brown Convention Center, city officials tweeting in Spanish and English that they “will not ask for immigration status or documentation from anyone at any shelter,” and Dallas opening a “mega shelter” at its own downtown convention facility. A neighbourhood northeast of the community was evacuated due to the risk of fire or explosion at a nearby chemical plant, and there were reports that an overflowing reservoir had breached a levee in Brazoria County.
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Harvey roared ashore onto the Texas coast on Friday night then paused over Houston. Tuesday morning found the storm stationary over the Gulf of Mexico southeast of Galveston. The U.S. National Weather Service forecast Harvey would eventually begin moving north again and make a second landfall near Lake Charles, LA, where the service warned of “a possibility of life-threatening inundation, from rising water moving inland.”
Meanwhile, Harvey’s location allowed it to sweep up vast volumes of warm Gulf water and drop it over the beleaguered city like a giant atmospheric pump. The continuing heavy rain, combined with water released from swollen reservoirs upstream on several waterways running through the city, meant floodwaters in many areas were expected to continue to rise through Wednesday.
With as many as 50 Texas counties affected by the storm even before it moves into Louisiana, Acting Homeland Security Secretary Elaine Duke told reporters at a Monday briefing, “we are not out of the woods yet, not by a long shot.”
By early Tuesday, officials had linked at least 10 deaths to the storm, including all six members of one family trapped in a car in a flooded street. Houston’s Bush International Airport remained closed and isolated amid flooded roads. The Houston Chronicle reported incidents of looting, and lineups as grocery stores tentatively began to reopen across the metropolitan area.
Power was slowly being restored to as many as 300,000 homes and businesses, but Houston Mayor Sylvester Turner announced that one of the city’s main water treatment plants was flooded and out of service, while another was producing only 5% of its normal output of safe drinking water. Homeland Security authorities, meanwhile, estimated that some 450,000 of the metro Houston area’s 6.7 million people would require assistance before the storm subsided.
For many, the continuing misery extended beyond rising floodwaters that threatened property and made movement difficult. As flooding submerged scores of petrochemical facilities and others initiated emergency shutdowns—operations that often involve unusual releases of process gases—residents trapped in many of Houston’s poorer communities reported “strong gas- and chemical-like smells coming from the many refineries and chemical plants,” CityLab reports.
“I’ve been smelling them all night, and off and on this morning,” grassroot environmental activist Bryan Parras said on Sunday. Other residents, he said, complained of “headaches, sore throat, scratchy throat, and itchy eyes.” The communities closest to refineries and petrochemical plants, CityLab notes, “are disproportionately low-income and minority.”
Donald and Melania Trump toured the less-devastated Corpus Christi area Tuesday, before reviewing emergency responses being coordinated from the state capital of Austin. Earlier, Trump pledged that “the federal government stands ready, willing, and able to support” what he said would be a “very expensive” cleanup effort.
Even as the rain continued to fall and the full extent of damages remained to be calculated, “early estimates suggest the financial damage [the storm] has inflicted has already run into tens of billions of dollars,” the Guardian reports, “and one forecaster has predicted the final bill could be as high as US$100 billion.” That would put Harvey in company with Hurricane Katrina, which did $120 billion in damage when it flooded New Orleans in 2005, and Hurricane Sandy, which left behind a $75-billion cleanup bill after it struck New Jersey and New York City in 2012.
“Damage to homes alone [from Harvey] could total $30 billion,” Charles Watson of data analytics firm Enki told the Guardian.
For many, those losses will be complete. Fewer than a third of households in the worst-affected areas are believed to have bought flood insurance offered by the National Flood Insurance Program, Watson added. That is partly because outdate flood maps failed to disclose that their homes were vulnerable.
Overall, Bloomberg estimated, “about 47% of Katrina losses were covered by the insurance industry, but only about 27% are expected to be insured for Harvey.”
And while Trump promised federal relief to the stricken region, the Washington Post notes that commitment faces potential roadblocks in Congress, where Texas’ Republican representatives voted solidly against providing emergency assistance to victims of Hurricane Sandy.
Even as the storm’s cost mounted, analysts looked for the causes of its ferocity, finding them both in nature and human activity. While hurricanes are natural events, several anthropogenic factors directly and indirectly amplified its power and constrained Houston’s resilience in the face of unprecedented volumes of rainfall.
Two factors in particular beefed up Harvey’s punch, scientists told the New York Times. Abnormally warm temperatures in the northern Gulf of Mexico intensified the hurricane’s strength and fed trillions of litres of extra water into the storm. Meanwhile, calm winds in the upper atmosphere allowed Harvey to stall over Houston, dumping that water on the city and its surroundings for days on end.
Climate scientist Michael Mann addressed the role of climate change in the storm’s dynamic in an extended Facebook post.
“While we cannot say climate change ‘caused’ Hurricane Harvey (that is an ill-posed question),” Mann asserted, “we can say that climate change worsened the impact of Hurricane Harvey in a way that greatly increased the risk of damage and loss of life.”
For one thing, he noted, “sea level rise attributable to climate change is more than half a foot over the past few decades. That means the storm surge [from Harvey] was a half foot higher than it would have been just decades ago, meaning far more flooding and destruction.”
Meanwhile, “there is a roughly 3% increase in average atmospheric moisture content for each 0.5ºC of warming. Sea surface temperatures in the area where Harvey intensified were 0.5 to 1.0ºC warmer than average temperatures. That means 3-5% more moisture in the atmosphere. That large amount of moisture meant the potential for much greater rainfalls and greater flooding.”
Mann also noted the growing evidence of a human influence in the lull in high-altitude winds that has allowed Harvey to remain in place longer than most tropical storms. “The stalling is due to very weak prevailing winds which are failing to steer the storm off to sea. This pattern,” the scientist notes, citing recent research, “appears to be favoured by human-caused climate change.”
Speaking to The Atlantic, Kevin Trenberth, a senior scientist at the U.S. National Center for Atmospheric Research, estimated the human contribution to Harvey’s stunning and persistent rainfall at 30%. “It may have been a strong storm, and it may have caused a lot of problems anyway,” Trenberth observed, but human-caused climate change “amplifies the damage considerably.”
So, argued several outlets, did poor planning and inadequate drainage infrastructure.
“Much of the Houston region’s flood planning is designed for so-called 100-year events, which have a 1% chance of occurring in any given year,” The Guardian notes. But “a flood of this magnitude is an 800-year event,” a Harris County administrator told the outlet on Monday. “It exceeds the design specifications of our levees.”
As well, the Texas Tribune adds, “unchecked development in the Houston area is wiping out the pasture land that once soaked up floodwaters. As millions have flocked to the metropolitan area in recent decades, local officials have largely rejected stricter building regulations, allowing developers to pave over acres of prairie land that once absorbed large amounts of rainwater.”
Meanwhile, the impacts of the storm began to be felt beyond Texas, as the near-total shutdown of the western hemisphere’s commercial oil capital and largest refining complex rippled through fossil energy markets. CBC News estimates the storm “has affected about 2.2 million barrels per day of refining capacity in the United States, including ExxonMobil, Shell, and Phillips 66 operations” in the Houston area.
“They are not making gasoline, they’re not making diesel fuel,” BMO Capital Markets Managing Director Randy Ollenberger told CBC, “so that’s tightening up those markets, not only here in North America, but globally.”
The national broadcaster predicted that Canadian drivers would begin to see the effect at gas pumps by today. Vancouver and most of B.C. can expect to pay about 3¢ per litre more, with the hikes rising across the country and highest in Montreal: “as much as a 15¢ increase to about C$127.9 a litre by mid-week.” In the Maritimes and Newfoundland, where gas prices are regulated, the CBC predicted that an “interruptor clause” would likely be triggered before the weekend to cap price rises.
Elsewhere in the world, Harvey’s effects could be felt in fuel shortages. “The United States is the world’s largest net fuel exporter,” Reuters observes. While Harvey remains stalled over the northern Gulf, the outlet notes, it is disrupting around one million barrels a day of fuel exports bound for Mexico and other Latin American destinations. “Mexico depends on U.S. fuel to meet nearly three-quarters of its domestic gasoline demand,” the news agency reports. “And most of those shipments sail from ports in Texas and Louisiana.”
Whatever other costs the superstorm ultimately extracts, one conclusion was unavoidable: Harvey may have been unprecedented, but it is unlikely to be unique. “Houston.” The Atlantic observes, citing meteorologist Eric Holthaus, “has seen four 100-year flooding events since the spring of 2015.”