The Ultimate Philly Weather Forecast

Think the weather we’ve seen in the last couple of years has been crazy? In the next few decades, Philadelphia could transform from a Northern city into what feels like a Southern one. And that could change everything about who we are.

A WEEK AFTER MY CONVERSATION with Katherine Gajewski, I’m standing inside the headquarters of a company called PJM Interconnection, wondering if I’ve somehow stumbled onto the set of Mission: Impossible.

In case you’ve never heard of PJM—which is located inside a couple of inconspicuous buildings inside an inconspicuous office park not far from the very conspicuous King of Prussia mall—it just might be one of the most important, highly secured (the guard confiscated my iPhone) companies in the entire Philly region. The firm is essentially responsible for managing the electrical grid of a big chunk of the eastern U.S.—13 states in all (plus D.C.), ranging from Illinois to New Jersey, with a population of about 60 million people. At the moment, I’m overlooking the guts of the operation: the super-high-tech control­ center,­ where giant electronic maps line the walls and colored lights flicker to show what’s happening on the grid. A couple of PJM employees are talking to me about last July’s heat wave, when the East Coast was smothered under triple-digit temperatures.­ (Philadelphia hit 103 degrees.) “We set a record for usage on July 21st,” says Adam Keech, a bearded guy who manages PJM’s control room. The load that day was 158,450 megawatts; on this December day, with the temperature outside in the low 50s, it’s 91,000 megawatts.

The good news about July 21st: Though there was an increase in staffing and intensity inside the control room, PJM managed to keep the power flowing pretty much everywhere it was needed. The less good news: It did so in part because a number of its industrial clients signed up to turn off or reduce their power for blocks of time. (They’re compensated by PJM for their sacrifice.) It’s a common practice in the energy industry, but it doesn’t necessarily bode well for what might happen if summer temperatures on the East Coast permanently park themselves at 90-plus degrees.

The blockbuster-movie-set feel of PJM is fitting, given some of the disaster-flick outcomes that theoretically could result if the Philly-as-Georgia model comes to pass. Tops among them: drought. According to the Pennsylvania Climate Adaptation­ Planning Report—a document commissioned by the legislature as part of the state’s Climate Change Act in 2008—prolonged droughts, brought on by increased summertime temperatures, are among the most threatening scenarios we’re likely to see in the decades ahead. Among the scary consequences: lack of drinking water, crippled crops, increased disease, even the threat of trouble at the state’s nuclear power plants if river levels drop too low. (Bucking for a supporting-actor nomination in the disaster-movie schema: bugs. That same planning report mentions the likelihood of whole different types of pests and pathogens invading Pennsylvania and threatening agriculture.)

Still, for all the drama associated with those outlines, the biggest challenges from climate change might come from quieter lifestyle shifts. Start, for example, with what we’ll be able to grow. The warm weather of the past few years has already had an impact on farming and gardening­—the Southern magnolia, which was once limited to growing zones from Florida to Virginia, can now thrive in Pennsylvania­—and that trend will continue in the decades ahead. Among the items that could be threatened: apple, grape and sweet-corn crops; maple, black cherry and hemlock trees; and Pennsylvania’s lucrative dairy industry. (Our literal cash cows would produce less milk as the weather heats up. Lucky for Wawa that it now makes a lot more money from coffee, gas and Shorties than from dairy.)

We’re also likely to see a significant shift in the fauna around us—both the birds in our trees (goodbye, white-throated­ sparrow) and the fish in our waters. “In Philadelphia, what you grew up seeing as a healthy stream—or the standard fish and critters living in it—would be totally different under a new climate regime,” says Chris Crockett, the city water department’s deputy­ commissioner of planning and environmental services. “For example, trout fishing is a big deal around here. But would the first day of fishing season be as big a deal in 50 years if we had the climate of southern Georgia? We wouldn’t even be able to get the trout to survive if the water was that temperature.”

And it’s not just fishermen who’d feel the difference. “Certain changes in climate will affect other recreational activities and how we view them,” Crockett continues. “And that will affect the recreational season. Instead of having three months out of the year, we might have nine.”

Crockett is right that the single biggest shift brought on by rising temperatures might be cultural, rather than physical­. Under the model used by the Union of Concerned Scientists, for example, one can imagine what we think of as spring-like weather starting sometime in February, while warm weather would last well into December. Which means you can pretty much say goodbye to traditional winter activities like skiing and snowboarding, not to mention certain local winter traditions, like the ice rink at Penn’s Landing and the ash-can fires lit by vendors at the Italian Market.

On the flip side, what would temperatures routinely cracking 100 degrees do to our quintessential summer activities? Would we still welcome America on the Fourth of July—or would Americans prefer to celebrate their independence with a nice long weekend in, say, Winnipeg? How about outdoor dining, which has so transformed Center City in the past 15 years—would we still want to sit outside at Parc or its 2050 equivalent when the heat index is 125? And what about sports? Pennsylvania’s climate-change report specifically notes that youth football in August and September would probably be so risky that the season might have to be moved. But what about the Eagles and Phillies? Would we have to follow the lead of Southern cities like Phoenix and Atlanta and erect domed or retractable-roof stadiums? If one out of every five days is over 90 degrees, will we have no choice but to become a hermetically sealed, perpetually air-conditioned city like Dallas?

Individually, none of these activities is essential. But collectively, they’re what give a place its color, texture and identity. To use an example from a state whose climate we may soon be appropriating: The peach has long been not only a staple of Georgia’s economy, but a symbol of the place itself. The most famous street in Atlanta is Peachtree Boulevard. For years, Atlantans celebrated the New Year with the Peach Bowl. Georgia itself is the Peach State. Alas, given the climate change coming to the southern U.S. (think: Central America), it may be tough to grow peaches there anymore. But one place the fruit might thrive? Right here in Pennsylvania.

Tom McGrath Tom McGrath, Chief Content and Strategy Officer of MetroCorp