Extreme heat, severe storms, flooding, and drought, already pose threats to the region’s built and natural environments. Modeling suggest that that future climate will become more severe and expose area communities and its residents to new hazards and heightened risks. As a result, looking at past climate patterns is no longer sufficient for long-term planning. In order to understand coastal vulnerabilities and to identify actions that could make communities more physically, ecologically, and economically resilient, it is necessary to first understand what climate related risks are expected. Using the best available climate science here’s what to expect for Southeast Pennsylvania:
Rising Temperatures: Average annual temperatures in southeastern Pennsylvania are projected to increase by 8 to 11 degrees Fahrenheit (°F) by the end of the century, relative to the 1981-2010 average (Union of Concerned Scientists, 2008).
Extreme Heat Events: The average number of days of extreme heat (above 90 °F) is anticipated to more than double on by mid-century compared to the current average (Union of Concerned Scientists, 2008).
Changing Precipitation Patterns and Drought: Increased winter precipitation will likely increase peak stream flows and flooding. Variable summer precipitation may lead to both flooding and short-term droughts.
Severe Storms: More frequent and heavier thunderstorms and downpours will lead to an increase in localized flooding.
Coastal Storms: Recent Nor’easters and hurricanes Floyd, Irene, and Sandy illustrate the severe impacts from coastal storms. These events are predicted to become more intense due to climate change, though they will still vary greatly from year to year.
Sea-level rise: Globally, sea level is expected to rise 2.5 to 6.5 feet by 2100 (National Research Council, 2010). The amount of rise in the Delaware Estuary will be even greater due to coastal subsidence, the sinking of land that results from natural geological processes (Partnership for the Delaware Estuary, 2011).