Not So As You'd Notice

America is getting hammered by severe weather events these days - hurricanes, tornadoes, floods, droughts - of steadily increasing frequency, intensity and duration. So what is the biggest killer of them all?

Heat.  Heat claims more American lives than any other weather/climate event.  And, in the future, more people will be baking than ever.

Vox has published a three-part series looking at worst-case scenarios based on climate modeling for Tampa Bay, Arizona and Southern California. Let's put it this way. All three of them are going to get stomped.

The big threat facing Tampa and most of Florida takes the form of sea level rise and hurricane driven storm surge. Think of a 24-foot wave of water. For California the gravest peril is from wildfires.  Arizona, like its neighbouring states, will bake the life out of its residents.

One day in the future, a massive wave of high-pressure air will park over Phoenix. 

As the sun rises amid an already scorching summer, the pressure will hold the accumulated heat in place and the triple-digit temperatures will tick up higher and higher. 119 degrees Fahrenheit. 120. 121. 122. Health officials will warn citizens to stay inside, but some will venture out and emergency room visits will spike. At night, the temperature will drop only to 100.

At this point, air conditioning is not a creature comfort. It is survival itself.

Over the next 24 hours of this heat wave, electricity use will surge higher as millions of air conditioners blast at full force, and the power grid will sputter as power lines strain. Power plants will run dangerously low on cooling water as the rivers that feed the region slow to a trickle and heat up. Generators will become less efficient.

The grid will succumb to brownouts and blackouts. Air conditioners will wheeze out, leaving many in homes that will grow dangerously hot. Water pumps will shut off, threatening people with dehydration. Freezers will thaw and food will spoil. Lines will form at gas stations as stalled pumps force drivers to refuel by hand. 

Anxiety will grow about the region’s water supply. The Phoenix metropolitan region will already be in a drought and what little water is left will start becoming too hot to use. The nearby water reservoirs will be at record lows. Golf courses turn yellow as water restrictions go into effect.

Gasoline will be in short supply as people start to leave the city. Traffic will gridlock as asphalt bubbles and roads close. Flights will be grounded as the heat makes the air too thin to generate enough lift for aircraft to safely take off and climb. Cacti will wilt. Air pollution will reach record levels as dust and ozone build up, leading to another spike in emergency room visits. 

This surging heat with temperatures peaking around the 120s will linger for two weeks, as rising average temperatures increase the length, severity, and frequency of extreme heat. The city’s economy will grind to a halt. Lights will switch off. By the end of this cascade, many may die.

Phoenix has already had more than one taste of this lash.

The hottest temperature recorded in Phoenix was 122 degrees in 1990. And a searing late-June heat wave in 2017 lasted more than a week and melted mailboxes. Letters slid off street signs. Asphalt bubbled. Airplanes couldn’t take off. Power consumption soared to record highs. There was no measurable rain during the month.

This isn't conjecture either.

[Arizona State engineering prof, Mikhail] Chester, who coauthored the study warning that Phoenix could face the Katrina of extreme heat, explained that losing power jeopardizes not just air conditioning, but traffic lights, commuter rail, water sanitation systems, even fuel pumps for gasoline. So a blackout or brownout during a time when the city needs energy the most stands to create a propagating series of failure and disruption, halting the economy and potentially taking lives. 

“Whether it is a hurricane in New Orleans or an [extreme heat event] in the Southwest, critical infrastructure systems are at risk for cascading failure in ways that are unpredictable and surprising due to their complex interdependencies and fragility to extreme conditions,” the authors wrote. 

“For each of these, you can find precedent,” Chester said. “We’re not just making up doomsday scenarios. In the Southwest, we’ve had these scenarios unfold.”

Florida, Southern California and the US Southwest are in deep kimchi. They may face different scourges but the impacts on their residents will be severe. At this point let's add a layer of complexity - mass migration out of Central America. How will the United States, reeling from natural disasters and having to rescue its own people, bear the burden of mass migration along their southern borders?

How could America care for climate refugees? How would it support them? Where would it put them? How would it balance the needs of an internally displaced population, American IDPs, and foreign migrants desperate for survival? There are few good options and many bad ones that I won't go into now. They're the stuff that keep planners busy at the Pentagon, Britain's Ministry of Defence and their counterparts in many other countries.