When the wind blows: why hurricanes are causing more havoc each year
On 25th August 2017 Hurricane Harvey, having ravaged the Caribbean, made landfall in the US where it caused damage to 100,000 homes – including catastrophic levels of flooding across Houston, Texas – and resulted in 106 deaths. In DG #28 we spoke to Katharine Hayhoe, director of the Texas-based Climate Science Center, about why hurricanes have been accelerating in frequency and intensity in recent decades
Illustrations: Christian Tate
25th August 2017 (Taken from: #28)
“This is a teachable moment,” says Katharine Hayhoe, a Texas-based climate scientist who’s in the ideal position to assess the long-term impact of a summer’s worth of storms – and not just the physical impact. She’s based in Texas, the state where Hurricane Harvey wreaked havoc in August 2017, and where many people hold sceptical or dismissive views regarding climate change. In her experience, however, such people become more open to the possibility that climate change is a real problem when it affects them personally.
“I live in West Texas and our Harvey, so to speak, arrived five years ago, a record-breaking drought in 2011 and 2012,” Hayhoe says. “The extreme heat changed the way people talked about climate change here.” In the aftermath of the 2017 hurricane season, she suggests, people would be asking the question – why is this happening?
“Climate change does not cause hurricanes,” says Hayhoe. “But there are multiple ways that climate change is interacting with and exacerbating the risk associated with any given hurricane.” She explains that in a warmer world more water evaporates, meaning that a storm has more water vapour to gather up and dump on the ground.
“The basic physics suggests that for every degree the world warms there’s six to seven percent more water vapour available. Harvey’s unusual track [it stalled over east Texas for days] was the most significant contributor to the record-breaking rainfall, but this rainfall was enhanced or amplified by the fact that it was occurring in a warmer world. If we’d had the same storm 100 years ago the precipitation would have been lower.”
A second factor is rising sea levels. “There’s more water and so the storm surges are getting stronger and a greater coastal area is flooded today than in the past,” she explains. “The third factor is that climate change is making hurricanes intensify at a rapid pace. Due to the extra heat trapped inside the Earth’s climate system by the greenhouse gases we emit, more heat is going into the ocean and there is more energy available to hurricanes.
“One study looking at hurricanes in the satellite era found that they are intensifying to category 3 winds, on average, nine hours faster today than they were 25 years ago. And Harvey [17th August to 2nd September 2017], Irma [30th August to 13th September 2017] and Maria [16th September to 2nd October 2017] were all rapid-intensification storms.”
Hayhoe says that increases in heavy precipitation don’t necessarily have to result in disastrous flooding as they did in Houston. She says that the city, with its “poor drainage, crumbling infrastructure and buildings built well within flood zones” would be “a poster child if you had to design a city to be vulnerable to heavy rainfall”.
This lack of preparation for a situation climate scientists had predicted for years raises the question: why aren’t Texan policymakers taking climate change seriously? “The vast majority of policymakers in Texas are dismissive of climate change,” she says, “and you could also say that about Washington DC now. But this does not reflect the opinion of the American people, not even those who identify as Republican or conservative.”
Hayhoe says that Americans’ belief in global warming should not be seen as a black-and-white issue but in terms of a spectrum, with ‘alarmed’ at one end and ‘dismissive’ at the other. “The dismissive group can’t be moved by any engagement, logic or argument, and this group is over-represented in Washington DC right now,” she says. “But the dismissive are only around 10 percent [of the country].”
Everybody else can be moved. “Most people are doubtful or disengaged because they’ve been repeatedly told that climate change is leftist, Communist, atheist etc,” she says. “They’ve been told they can’t be themselves, Christian or conservative, and care about climate change. What works is to connect the dots between the values people already have and the issue of climate change, and show them that they are exactly the type of person to care about it.”
Hayhoe’s message that caring about climate change is more than compatible with Christ’s teachings didn’t go unnoticed by Barack Obama, who sat with her and Leonardo DiCaprio on the lawn of the White House for a public discussion on climate change on 3rd October 2016.
Hayhoe says that the vast majority of Americans now accept that the climate is changing. And while many of these people may be unwilling to accept that humans are causing this change, they will support measures such as “building resilience, adapting clean energy efficiency, investing in renewables, funding research and development”. And that’s ultimately what matters most.
“It’s becoming easier to gain consensus and momentum around the idea that we need to prepare for disasters and risks that are being exacerbated without necessarily having to agree on why they’re being exacerbated,” Hayhoe says. “To prepare for a changing climate, we don’t have to agree on why it’s changing. We just have to agree that it is.”
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