Climate Change Projections for NYC

Climate Change is a global problem with impacts that vary from place to place. In New York City, they include hotter temperatures, heavier precipitation events, rising sea levels, and increased flooding. Each one of these local challenges was spelled out in detail by the latest report from the New York City Panel on Climate Change (NPCC).

According to the report, temperatures are expected to increase between 4.1°F and 5.7°F by the 2050s and between 5.3°F and 8.8°F by the 2080s. The frequency of heat waves is forecast to jump from the current average of 2 per year to 6 by the end of century.

Annual precipitation is projected to increase 4% to 11% by the 2050s and 5% to 13% by the 2080s. The report also calls for the number of days with extreme precipitation – heavy rain and snow – to increase 1.5 times by the 2080s.

Local sea levels are expected to rise between 11 inches and 21 inches by the 2050s, 18 inches to 39 inches by the 2080s, and up to six feet by 2100. As an archipelago, NYC is especially vulnerable to sea level rise. Higher sea levels give storm surges a higher starting point, allowing floodwaters to reach further inland. That means Sandy-like flooding will become more probable in the future even with a less powerful storm. In fact, if the high end projections of sea level rise come to fruition, the current 1-in-100 year flood event could happen roughly every 8 years.  The city’s flood zone is expected to double in size by 2100.

These changes are not only significant for their quantities, but also for the rate at which they are forecast to occur.  To put them into perspective, compare them to the recent past. Between 1900 and 2013, the city’s annual temperature increased 3.4°F, mean annual precipitation increased 8 inches, and local sea levels rose by 1.1 feet.

Taking steps to both adapt to and mitigate climate change, NYC has started building flood protection systems and has pledged to reduce its greenhouse gas emissions 80% from 2005 levels by 2050.

Formed in 2008, the NPCC assesses the latest climate science and analyzes the specific impacts facing NYC.  It issues a report every 3 years.

Credit: NPCC 2015 Report

NYC faces an increasing risk of floods due to sea level rise and climate change.                          Credit: NPCC 2015 Report