Climate change: New York's program to cool down its streets.

Million Trees NYC: Planting Trees to Green the City and Combat Urban Heat

In 2007, Michael Bloomberg launched the Million Trees NYC program with the ambitious goal of planting one million trees by 2017. However, thanks to sustained efforts, the city had achieved this goal in 2015, two years earlier than planned.

The Million Trees NYC program has been hailed as a successful model of urban greening and has inspired other cities around the world to follow its example. But it was not just about greening for the beauty of the city. Trees have very concrete benefits for combating the effects of urban heat.

Urban heat is a phenomenon in which urban areas have higher temperatures than surrounding rural areas due to the accumulation of heat in buildings, roads, and other surfaces. This can lead to health problems such as heat stroke and heart disease, as well as high air conditioning costs for buildings.

This is where trees come in. Trees provide shade and absorb heat, which helps to reduce temperatures in urban areas. In addition, trees absorb carbon dioxide and other air pollutants, helping to improve air quality. They also help to reduce flooding by absorbing rainwater and preventing soil erosion.

To maximize the benefits of trees for combating urban heat, the city of New York has launched a targeted tree-planting program for the most vulnerable neighborhoods. Using the city's heat vulnerability index, which identifies neighborhoods most at risk from heat-related hazards, the tree-planting program prioritizes areas in the South Bronx, Northern Manhattan, and Central Brooklyn.

The program has also implemented initiatives to encourage residents to plant trees in their own gardens and living spaces, thus creating a culture of arboriculture throughout the city.

Thanks to these efforts, the city of New York has created cooler and more pleasant areas for residents while reducing air conditioning costs for buildings. In addition, tree planting contributes to the fight against climate change by absorbing carbon dioxide and improving air quality.

In summary, the Million Trees NYC program of the city of New York highlights the importance of urban vegetation in combating the effects of urban heat and improving quality of life.

Environmentally conscious New Yorkers as well as local authorities have encouraged the Adams administration to have an ambitious vision to expand the city's canopy by planting an additional million trees by the end of the decade. However, the mayor did not fulfill his promise to double funding for the parks department. Instead, he allocated a budget for about 20,000 trees per year, which represents a decrease from previous years.

Cool Roofs

The NYC °CoolRoofs program in New York City aims to reduce the urban heat island effect by promoting the installation of white roofs, green roofs, and cool roofs, which reduce energy consumption and maintenance costs. Since its launch in 2009, the program has covered over 6.7 million square feet of roof space, contributing to the reduction of carbon dioxide emissions in the city. The benefits of cool roofs include a reduction in air conditioning costs, improved comfort for residents, increased roof and equipment lifespan, as well as aesthetic and financial benefits for owners. The program also offers free cool roof installations for non-profit organizations, housing cooperatives, and public agencies, as well as technical assistance and low-cost installation options for other private buildings. By installing a cool roof, a building can reduce air conditioning costs by 10% to 30%. Additionally, it can achieve a reduction of up to 30% in internal temperatures during summer, which has a positive impact on heating costs in winter. Furthermore, this can improve the sustainability of roofs and building equipment, as well as the comfort of residents and tenants in the building.

Understanding the role of cool pavements in combating the urban heat island effect

The surface of cities contributes to the urban heat island effect. Just like dark roofs, asphalt pavements re-emit absorbed heat back into the atmosphere, especially at night. On the other hand, "cool pavements" used on sidewalks, bike paths, and playgrounds are typically light-colored pavements with high albedo* (greater than 0.29) that reflect more solar radiation than a dark pavement with low albedo. City simulations, using meteorological data from several American cities, have shown that reflective pavements, when used in conjunction with cool roofs and shaded tree plantings, can lower ambient air temperatures by an average of 4°F to 9°F. Additionally, it has been suggested that cool pavements with high albedo surfaces can have longer durability due to their lower temperatures, and can reduce stress on street trees, thus increasing their vitality and the benefits they provide.

*albedo: the measure of a surface's reflectivity.

The plan also includes providing training for healthcare workers on climate risks, as well as encouraging New Yorkers to check on at-risk neighbors via Be a Buddy NYC. Partnerships between health and weather are established to ensure good communication. Additionally, the plan promotes the improvement of window insulation for homeowners and includes an energy assistance program for low-income households (LIHEAP). Finally, free cooling centers are activated during heat waves to provide air-conditioned space for the public.

Trees map NYC: https://tree-map.nycgovparks.org/