Rising Temperatures and The Urban Heat Island: What it Means NYC

If you have been keeping up with the news lately, you are bound to have heard that this year is projected to be one of the hottest on record … again. According to data from NOAA, 2018 is projected to be the fourth-hottest year on record, only beaten by 2016, 2015 and 2017. Heat waves in Tokyo, Montreal, and Los Angeles, over the Summer months have been devastating the communities there, as hundreds have been hospitalized and dozens even dying as a result of heat-related reasons.

So, what does this mean for New York? Well, like these other cities, New York suffers from increased temperatures compared to its suburbs and exurbs due to a phenomenon called the urban heat island effect. Like climate change, the heat island effect occurs due to human activity and causes include lack of vegetation and traditional urban design choices. Design choices such as widespread concrete, asphalt, tall buildings, dark colored paints and building materials allow for a higher level of solar radiation absorption that, in turn, traps more heat. Tall buildings not only provide more surface area for solar radiation to absorb into, they also block the normal wind patterns (this is especially true in Manhattan with the sheer amount of skyscrapers). Vegetation is critical, as well, due to the process of evapotranspiration in addition to the shade that trees provide. Evapotranspiration can reduce peak summer temperature by 2-9 degrees and shaded surfaces can be between 20 and 40 degrees cooler than the surrounding area.

Overall, the heat island effect can make a city 2 to 5 degrees warmer during the day and up to 22 degrees warmer at night than the surrounding suburbs and exurbs. The difference in nighttime temperature is especially crucial considering the body needs the time to cool down. The extreme heat can cause dehydration that might ultimately lead to heat stroke or heat exhaustion. Heat actually leads to more emergency room visits per year than any other extreme weather event, 450 per year on average according to the New York City Mayor’s office. If temperatures continue to rise, we can expect that number to, as well. Between 1,552 and 3,331 deaths are expected annually in NYC by 2080 depending on emissions levels moving forward. The New York City Panel on Climate Change also predicts around double the number of days above 90 degrees in the city by 2050.

Often, during the hottest days of the year, the temperatures indoors are actually hotter than those outside. This puts those who have a hard time going out or without air conditioning at the highest risk of being hospitalized due to heat. Many low-income areas already have a much lower rate of parks and green spaces, but that coupled with not being able to afford air conditioning or the added electricity cost associated with air conditioning makes them particularly vulnerable. People with disabilities and the elderly are also at a much higher risk of being affected, as its harder for them to leave their home and make their way to city-designated cooling centers.

With all this in mind, there are a multitude of solutions to counteract the urban heat island effect and the city is already making efforts to implement some of them. Since 2009, the NYC CoolRoofs project has been painting city rooftops with a white, highly reflective coating that reduces heat absorption compared to a darker coating. This reduces temperatures in the surrounding area and can reduce building temperature by up to 30 percent. The program offers no-cost installation to non-profits, affordable/low-income housing, community centers, schools, and more. In 2017, the mayor’s office announced its commitment to mitigating the effects of extreme heat through a new initiative called Cool Neighborhoods NYC. This is an extensive, $106 million project that touches upon many of the problems that desperately need to be addressed – $82 million of the project’s budget, alone, will go to planting trees in the South Bronx, Northern Manhattan and Central Brooklyn (the neighborhoods with the highest level of heat vulnerability and some of the lowest overall vegetation). The initiative also launched a pilot program for community cohesion called Be a Buddy NYC. One of the most overlooked aspects of dealing with extreme heat is making sure everyone is aware of the risks and can safely and easily do whatever they can to counteract them. The program focuses on spreading awareness of cooling center locations and having a buddy system in place to assist community members in the case of an emergency.

To stay up to date on the latest extreme heat warnings and communications, you can download the Notify NYC app. You can also find your nearest cooling center here or by calling 311.