1. Sea level could rise over 4 feet by the 2080s.
A 2009 report [PDF] issued by the New York City Panel on Climate Change (a group of climatologists, geographers, economists, and consultants convened by Mayor Bloomberg) includes the following projected sea level increases:
• 2–5 inches by the 2020s
• 7–12 inches by the 2050s
• 12–23 inches by the 2080s
And those estimates don’t take into account certain changes in rates of polar ice-cap melt over time. Another method that incorporates those projects a rise of 41 to 55 inches (or over 4 ft) by the 2080s. What would that look like? A simulation via Flood Maps is above — much of Battery Park City and Red Hook (both of which were heavily flooded by Sandy) could be underwater.
2. Floods of Sandy proportions could happen a lot more often.
The NPCC report also estimates how frequent major floods will become in New York’s future. Right now, a flood of 8.6 feet or more is considered a 100-year flood, meaning it has a 1 in 100 chance of happening in any given year. Sandy appears to have been that bad (or worse). But by the 2080s, floods this major could happen once every 15 to 35 years, not once a century. Smaller floods, the kind that currently happen about once every ten years, could happen yearly.
3. And more of the land will probably flood.
William Solecki, a geography professor and coauthor of the report, says that the rise in sea level might not be such a big deal on a normal day. But if there’s a storm, that means “that extra amount of water is available to move inland.” The extra water would mean more flooding, especially in parts of Brooklyn and Queens that are very flat.
4. The city could have two to four times as many heat waves every year.
Of course, climate change isn’t just about storms. Temperatures could also rise. New York currently has about 2 heat waves (spates of three or more days above 90 degrees) a year — the NPCC report estimates that we’ll see 3 to 4 a year by the 2020s, and 5 to 8 by the 2080s. And while the city currently averages about 14 days a year above 90 degrees, that could go up to between 37 and 64 days by the 2080s.
5. Intense rainstorms (and droughts) could become more common.
The NPCC says big rainstorms and droughts are both likely to become more frequent as the 21st century progresses. Solecki points out that while we’re focused on flooding of coastal areas caused by Sandy right now, heavy rains can cause inland flooding too.
6. Extreme wind storms could become more frequent too.
“Intense hurricanes and associated extreme wind events will more likely than not become more frequent due to expected warming of the upper ocean,” writes the NPCC panel. They’re less confident about predicting wind than other climate changes though, because its affected by a variety of ocean and atmospheric factors.
7. The city’s subways, sewers, water supply, and power grid could all face more damage.
The post-Sandy flooding and power outage could be just the beginning. The NPCC reported that all the weather changes over the coming decades could cause the following infrastructural problems for New York:
• sewer overflows that pollute waterways
• saltwater pushing into rivers, limiting water supply
• increased pollution released from waste sites
• erosion of beaches and salt marshes
• flooding of wastewater treatment plants
• increased bacteria load in reservoirs
• degradation of city equipment from saltwater corrosion, flooding, or high temperatures
• and, of course, more loss of transportation service and more power outages
There’s hope, though. Since the report was published in 2009, Solecki says the city has made some changes, like removing train cars from flood-prone yards in the advance of a storm, that could make it less vulnerable to climate change-related disasters. And, he says, even though not everyone is convinced that climate change is real, events like Sandy “raise that specter” in people’s minds and get them talking about it. He notes that his local radio sportscaster was discussing climate change on Wednesday in the wake of the storm, and the fact that awareness of climate issues had reached local sports radio was significant. “These events always open a window for talking about things,” he says. Now the question is how long that window will stay open, and whether we’ll graduate from talking to acting.