Along with other industries, cities have been devastated by climate change. The vast majority of Americans, and most people around the world, are in cities, and more than 90 percent of the city-planting that is necessary to avert dangerous climate change will not be done in this century.
According to an analysis by the Natural Resources Defense Council, nearly 1.3 million people have died in cold snaps in the past 30 years, and fires have burned twice as often. Small earthquakes are hitting the city almost three times as often. So many summers in New York have been unusually hot and dry that New York state declared a state of emergency. The effects of climate change have been particularly on display this summer: A lot of trees have died from the heat and drought. In New York, close to 40 percent of the urban forest has died.
Related: Greening America
The NRDC report points out that without climate change, New York City would need only 900,000 trees, and that to tackle these issues, urban forests should add to the 6 billion trees already already planted in the city’s urban core and suburbs.
Related: Climate change from a climate scientist’s perspective
So why are these diminishing urban forests having such an impact? First, because they act as natural carbon sinks. Trees absorb atmospheric carbon dioxide and release oxygen, so the more trees there are in cities, the greater the levels of carbon that get absorbed — and the less there is to add to the atmosphere.
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Second, each outdoor growing tree consumes approximately 2 gallons of water, saving about 600 gallons of rainwater per year, according to analysis by City Water Services, a unit of the city’s Department of Environmental Protection. Losing urban forests means running out of rainwater to flood streets.
Third, because trees are free, the smaller number of urban trees reduces the number of trees — collectively — that can replace the ones that have died. A tree in a large urban area, says City Water Services, requires 25 gallons of water to grow to maturity. A single tree can still potentially replace a handful of smaller trees. Without the growth of new trees, entire tree populations will die — and they are plants, and not animals, that can die.
Fourth, urban forest loss can cause problems with air quality. Ground-level ozone pollution is the main ozone problem for cities. Trees pull air into their canopy, reducing ground-level ozone levels. Even though ground-level ozone and particulate matter are at relatively low levels in cities during much of the summer, they can still be harmful for healthy people, including those with asthma.
Related: This is what the desert is like right now in the U.S. And the situation gets worse for the millions of Americans who live near fossil fuel infrastructure. “Today,” the NRDC reports, “chemical and mining operations are contaminating forests near nearly 2 million acres of fossil fuel infrastructure. In some places, our forests are standing in for tanks, pipelines, and other dirty fuel equipment.”
