City Hall Gets Ready for the Rising Tide

Climate change could put parts of Philadelphia under water by 2100. The city's sustainability office is preparing for whatever might come up the rivers.

We’re only halfway through the 2010s, and to date, the decade has produced the two warmest summers, the snowiest winter, the wettest day and the two wettest years on record  — along with two hurricanes and a derecho, a storm containing straight-line winds strong enough to produce damage on the scale of a hurricane or tornado. Climate change caused by the greenhouse effect is likely to give us more of the same, according to climate research conducted by ICF International. And along with those greater extremes could come something else: an accelerating rate of sea level rise that could by 2100 put much of the low-lying land along the Delaware River under water and flood key evacuation routes if a Category 1 hurricane, the strongest yet to hit the city, came along.

Given these possible scenarios, the Mayor’s Office of Sustainability decided it was time to take stock of the city’s assets and see what might need to be done to make them more climate-proof as the climate changes.

The report “Growing Stronger: Toward a Climate-Ready Philadelphia,” released Dec. 2 by the office,  describes simple steps city departments and agencies could take now and in the very near term in order to reduce the vulnerability of city assets to damage or loss due to extreme weather and climate change.

The actions recommended in the report include such things as moving city-owned vehicles from facilities that might flood in the event of a major storm to higher and drier ones, factoring climate risks into the Department of Public Property’s maintenance policies, rewriting specifications for equipment such as air conditioners to ensure they perform well in warmer and wetter conditions, and coordinating preparations for extreme weather events across departments as storms approach.

While no city assets are in imminent danger of winding up under water, one asset in particular may prove more susceptible than the others to serious disruption from climate change: Philadelphia International Airport, much of which occupies what was once marshland along the Delaware River. Under most of the scenarios described in the report, parts of the airport could be flooded, and in a worst-case scenario, such as a 500-year flood or a Category 1 storm surge combined with a four-foot rise in sea level, just about all of it would be.

“Regarding the airport in particular, current projections suggest the best course of action would be to harden particular vulnerable assets such as substations rather than consider a wholesale relocation of the facility,”said Sarah Wu, deputy director for planning in the Mayor’s Office of Sustainability.  “As the range of potential future sea level rise scenarios narrows, PHL may need to consider more transformative adaptation options.”

How much would these preparations cost the city? Wu said that the purpose of the report was not to put a price tag on specific strategies or actions. But the analysis was performed and recommendations made with an eye on picking the low-hanging fruit first. “The early-implementation actions went through an initial screen for costs, and ICF, our climate consultants, deemed the strategies in those sections relatively low-cost,” said Wu.

Meanwhile, the city is also pursuing a strategy aimed at reducing its greenhouse-gas emissions 80 percent below 2012 levels by 2050, enlisting a research team at Drexel University to help figure out how this can be achieved.

The full report is available for view or download as a PDF from the city’s website.