About the Metropolitan Transportation Authority Subway System

Since its inception more than one hundred years ago, the MTA Rail System has asserted itself as an integral part of the New York experience, growing from serving only Manhattan to the entire state and even parts of Connecticut. As a whole, the MTA Rail System serves approximately 2 billion people and operates on over 2,000 miles of track, and the most utilized aspect of this larger system—the subway system—is a staple of daily transportation for New Yorkers and tourists alike.[1] A system so large that caters to such a massive population must continue to be strong and dependable for efficient operation of everyday life. This staple of New York may, however, be in danger due to the effects of climate change.

Contents

1. About The Metropolitan Transportation Authority Subway System
2. The Effects of Climate Change on the Subway System
3. Consequences of Vulnerability
4. Planned Action for Adaptation
5. Citations
 

 
 
Effects of Climate Change on the Subway System

Due to the effects of climate change, the average annual temperature is expected to rise from 2˚F to 12˚F by the end of the century with the amount of hot days (days with temperature over 100˚F) in New York increasing from one to two per year in the 1990s to eight by 2100. In the business-as-usual scenario (doing nothing to mitigate climate change), New York will have up to 70 days per year with temperature over 90˚F whereas in an environmental-friendly scenario we can reduce the number of hot days to only 38. [2] An economic and environmental consequence of these more frequent hot days will be the greater amount of energy needed for cooling subway cars and stations. For bridges and tunnels, these hotter temperatures would cause the suspended main spans to sag, posing a safety concern.

Figure 1. Average temperatures in the Northeast have increased by over 1.5˚F since 1970. Under the business-as-usual scenario, temperature is expected to rise by 6°F to 14°F by 2100, causing New York City to have a dramatic increase in the number of days over 90°F and 100°F. If an environmental-friendly approach were implemented, temperatures would only rise by 3˚F to 7˚F. (http://www.geo.cornell.edu/eas/energy/research_front_page/climate_change.html).

After the first half of the century, the average annual precipitation is expected to increase by 5% to 15% .  By 2100, the number of days with rains exceeding two inches will increase by a factor of 1.4 under the environmental-friendly scenario and a factor of 1.6 under the business-as-usual scenario, the consequences of which being the overflow of sewer drainage systems, holding tanks, disposal systems and city waste water treatment plants. The capacities of all these systems are too low for the upcoming precipitation increase and there will be a greater need for water pumping systems to manage the excessive run-off and flooding of underground subway stations. With this greater need for pumping comes a greater reservoir of energy to power the pumping stations.

Figure 2. By 2100, heavy rainfalls are expected to increase while the light rainfalls are expected to decrease, leading greater chances for extreme weather conditions like droughts and flooding (U.S. Department of Agriculture – Forest Service).

The most problematic climate change issue for the subway system deals with rising sea levels and coastal storm surges. The normal rising rate for the sea level in New York City has been 0.96 feet per century, but as the hotter temperatures warm the ocean, the water will expand and cause the sea level to rise at a faster rate. In addition to this ocean water expansion, the hotter temperatures will cause land ice to melt, increasing the ocean’s water volume. The changing winds and currents associated with warmer temperatures will diminish shorelines and increase ocean height (surges), and coastal land elevation such as the caving in or uplifting or coastal shores will exacerbate the impact of storm surges and rising sea levels. Since there is no known maximum at which sea level rise will gradually stabilize, this trend could serve to be detrimental to the subway system, as the sea level could increase by one to two meters by the end of the century, flooding lower lying areas of New York. Under current conditions, coastal storm surges are able to reach a height of ten feet, but as the sea level rises, the impact of storms and surges will only become worse: “A 100-year storm is likely to be reached by a weaker 10-year storm because its weaker surge is superimposed on a higher mean sea level”(15). [2]  A storm that would not be devastating now could prove catastrophic in the future due to the overall projected rise in sea level; flooding of the underground subways can indefinitely halt transit services, cause power outages, corrode infrastructure, clog sewer systems and spread unsanitary debris. Such an event would cause an unprecedented economic toll, and the energy required to fix these problems would just add on to the CO₂ emissions [1]. This vicious cycle needs to be modified so that New York can better adapt to climate change before such effects are realized.

Figure 3. The expected state of New York City if sea levels rise 1 to 2 meters and a storm hits. The FDR Drive and parts of Wall Street would be underwater and NY infrastructure, sewage systems, and transportation systems would be ruined by corrosive saltwater (http://www.wnyc.org/articles/wnyc-news/2011/feb/09/climate-change/).

– Shivani Sharma

 

 
 
Consequences of Vulnerability: Why NY Needs to Adapt

As a city so near the coast, New York City is vulnerable to the various accompanying ills—such as tropical storms and flooding—that come with coastal life. Possibly most at risk is the subway system, which travels for the most part below sea level across most of the metropolitan area. As temperatures and sea levels rise, so does flooding, decay, and deterioration within the subway system, and these effects are compounded with coastal storms that attack with an increasing fury. According to the MTA, “The coastal inundation flood risks are increasing because future storm surges will be superimposed on the ever-rising sea levels”, and when it comes to costs and damages incurred throughout the city after a storm, “The MTA would incur a substantial percentage of these losses.”[2]

In light of these facts, it becomes increasingly important to know where subways are most vulnerable. Unfortunately, “At this time a systematic assessment of the vulnerabilities to climate change of MTA’s assets, operations and financial health does not exist.”[2] This is something that obviously needs to change. There is, however, a very informal listing of key vulnerabilities. For instance, there are 228 miles of subway track in NYC and whether they are below sea-level or elevated, the tracks are vulnerable to a slew of weather conditions: extreme heat and humidity, extreme cold, extreme precipitation, and extreme winds; some of which lead to flooding from run-off, underground seepage, or storm inundation. With higher temperature come power failures and increases in rail degradation and equipment deterioration such as sagging lines, which will cause collisions and delays. Accompanying all these extremes is the need for excessive use of cooling, heating, and pumping equipment, all of which cost more money (in labor costs and equipment costs), use more energy, and cause more delays [1]. We also must keep in mind that these extreme conditions aren’t so uncommon anymore because of climate change. These problems are becoming the norm.

Figure 4. Despite the fact that the subway system is highly susceptible to flooding as seen by this post-Sandy picture of the South Ferry station, there is no systematic assessment of the subway system as of yet. (The Atlantic)

New York must adapt because continuing as it has been is out of the question. The subways are crumbling under the conditions of climate change and the toll taken will cause a domino effect amounting to mind-boggling costs. But monetary concerns are the least of New York’s concerns if adaptation doesn’t occur. The citizens and tourists of New York City rely on the subway: it is the circulation system of the city, pumping its contents from point A to point B every day, every hour, every second. When that circulation stops, its passengers coagulate and scab. People are stranded away from work, away from home, and away from loved ones. In disaster situations, passengers are cut off from necessary resources such as food, clothing, and shelter.

Figure 5. Millions of people rely on the subway daily for transportation from Point A to Point B. If the system is not prepared for storms like Sandy, commuters could be trapped in trains or stations away from food and water, unable to get help. (The Atlantic)

Hurricane Sandy provided the ultimate example of what sort of chaos the subway system can be subjected to. Sandy began as a typical tropical cyclone with symmetrical wind fields revolving around a warm-center that drew energy from warm waters of the tropical Atlantic. But Sandy soon grew unique as she moved north and melded with western weather system. This changed Sandy from a tropical cyclone to an extra-tropical cyclone: a different kind of beast entirely. Fueled by the sharp contrast between convergent temperatures, these storms can become asymmetrical with a cloud pattern resembling a comma, which stretches far further than a regular tropical cyclone. For instance, Hurricane Katrina, a regular tropical cyclone, had a cloud span of 300 miles, whereas Sandy’s spanned 900 miles [3].  By now, we know that Sandy was an incredibly destructive storm but, as mentioned before, Sandy did more than just decimate a city. She provided a preview of what’s to come: “Storm inundations can give us today a preview (albeit amplified, reversible and only for the storm’s duration) of what sea level rise will produce ever more irreversibly during decades and centuries to come.”[2] The whole Sandy situation and all its repercussions was just a microcosm of what the world and subways soon could be without proper adaptation. Subways were shut down before the storm hit and rightly so, as some subway tunnels were flooded as much as twenty feet. In the days after the storm, people walked miles to their homes or work places, transforming their commute from a quick ride on the subway to a two-hour trek each morning and night. Even now, weeks after the storm, many rail lines have yet to return to a completely normal schedule. Hurricane Sandy provided a harsh reality for New Yorkers. Through a metaphorical meteorological act of tough love, we’ve come to realize that something must change.

– Adrian Savage

 

 
 
Planned Action for Adaptation

For the proposed end of the century scenarios, the main effects of climate changes are temperature rise (number of extreme hot days), changes in precipitation (number of extreme rainfall), sea level rise, and coastal storm surge. This includes changes in the frequency, intensity, and duration of heat waves, droughts, inland and coastal flooding, saltwater intrusion, and the effects of heat and humidity on everyday life. There are many highly possible prevention propositions that deal with flooding, power failures, and CO₂ emissions, and they should be looked into as soon as possible.

Figure 6. This is what the next century has in store for New York City. Oceans are expected to rise between 1 to 2 meters, enough to submerge many cities in the U.S. East Coast (National Geographic).

“But no agency and system-wide climate risk assessment plan is currently available, nor had it been contemplated.” (22)[2] Before tackling the problem of climate change, the Metropolitan Transportation Authority (MTA) first needs to assess their subway system. The first planned action for climate adaptation needs to be an evaluation of the transportation structures that are most vulnerable and valuable. Vulnerability is determined in terms of location and structures that are most susceptible to sea level rise and storms while value is determined in terms of climate induced economic toll and revenue loss coupled with the cost of adaptation. The MTA has to take into account climate change and its challenges and assess critical tasks that require reformation, dedication, and evaluation of costs and benefits. Their leadership has to branch out on a local, state, and federal level so that the public and the multiple agencies involved in the transit system will be able to work together towards one common goal: a climate resilient transportation system.

The single most important issue with combating climate change and implementing adaptation reforms in subways, railroads, bridges, and tunnels is the disorganization of the multiple agencies that control New York City’s transportation and infrastructures. Communication and cooperation between these agencies in New York is required, especially when change in one existing infrastructure by one agency affects the infrastructure owned by another.  Agencies such as PANYNJ PATH, ARC/Penn Station, NJ Transit, Amtrak, and others will be affected by the coming climate change, and the MTA will need to get in touch with these and many more agencies as certain long-term solutions affect businesses and residency.

Certain geographic areas are at the lowest critical elevation for sea level and should be of main concern. Much of Lower Manhattan is a main concern for sea level rise; the World Trade Center and the A, C, M, N, and R Lines are only seven to eight feet above sea level. Most of the Long Island Rail Road (such as East River Tunnels, Long Beach Branch, and Penn Station Tunnel) has a lowest critical elevation below ten feet.  Even certain bridges and tunnels such as the Queens Midtown Tunnel, Brooklyn Battery Tunnel, and Verrazano Narrows Bridge are at risk of flooding with a lowest critical elevation of eleven feet or below.[2] Along with these low-lying areas are certain ventilation facilities and manholes that should be closely examined in location and structure [1]. These are some of the MTA’s assets that have the highest risks and should be handled first.

Figure 7. MTA workers covering subway ventilation grates with plywood to help prevent flooding at South Ferry, New York City in anticipation for Hurricane Sandy (Couriernews.com).

Since sea levels will indefinitely rise and storm surges will indefinitely worsen, the only worthwhile plan so far is the relocation of the subway systems. In order to adapt to the rising sea levels and storm surges, subways need to be moved to higher grounds at a certain elevation. The finances and investments needed to make this plan possible, however, are too costly and thus unlikely to happen in the near future. Fortunately, there are other solutions that are less costly and equally as effective. A long-term form of adaptation is to modify and redesign current subway projects that are already underway.  Currently, the Long Island Rail Road is being extended to Grand Central Station, the 7 Train is being extended to West Manhattan, and the South Ferry Terminal, lines in Lower Manhattan, and Fulton Street Transit Center are all being renovated for customer convenience.[2] The MTA has to assess the earliest possible time when these projects are still flexible enough to be altered for climate change adaptation. If they do not start now or in the near future, the MTA will have to consider developing floating structures with an anchor and ability to withstand intense weather.

Additional long-term planned actions for adaptation that are not as feasible as the aforementioned plans include engineering innovations and technological advancements.  For example, increasing the street elevation of flood-prone areas like Lower Manhattan would mitigate the area’s flooding risks. Another solution would be to install storm barriers all around the New York – New Jersey Harbor, but this method would prove costly and temporary due to the rising sea level. An innovative and probable proposal that has been recently tested is an inflatable plug that has the ability to seal tunnels to prevent subway flooding. The device uses three layers of Vectran, a very strong lightweight and stretchable material.  This balloon-like plug essentially consumes the oncoming water from a flood with very little seepage. The design is expected to be completed in a few more years and will cost about $400,000 per unit. The plan has $8 million invested so far in an attempt to, according to Homeland Security’s project manager Dr. Fortune, “to reduce the unmanageable to manageable” [4]

Figure 8. An inflatable device that could save tunnels from flooding. (NY Times)

Furthermore, there are some short-to-mid-term solutions that could be developed and invested to adapt to climate change. Permeable pavements and surfaces like those in parking lots that drain much of the water into the ground can be implemented as well as roof catchments that can collect two inches of rainfall, which can lead to gray water (waste-water that is neither clean nor sewage) usage. Raising or closing subway curbs and grates can dramatically reduce water flow during extreme storms, and subway ventilation grates can remain partially or completely closed in fear of floods.[2] Photovoltaic roofs and geothermal heat pumps don’t rely on fossil fuels and can reduce energy usage and its effects on the climate, and as the usage of air-conditioning and heating will begin to rise as the number of hot and wet days do, solar and geothermal energy can greatly reduce New York’s fuel energy consumption.

Figure 9. Imagine this photovoltaic panel on the roof of all subways and buses rather than just houses. Although installation can be costly and management can be time-consuming, this idea could serve as an effective way to reduce energy consumption (National Renewable Energy Laboratory).

There are many climate prevention and adaptation possibilities for New York, the MTA, and all agencies involved. Some are more economically and technologically feasible than others, but all are worth considering.  The public, the government, agencies, and organizations must come together to aid and invest in New York’s oldest and most dependable transportation system before it is too late. Temperatures will increase, sea levels will rise, and coastal surges will only worsen. The better the Metropolitan Transportation Authority understands this the earlier we can adapt.

– Shivani Sharma

What About the Rest of The World?

Climate change is a global phenomenon, and transportation systems all over the world are faced with the challenge of adapting to the possible consequences. Specifically, the Filipino area Metro Manila draws a parallel to our New York-based transportation adaptation observations. As an archipelago off the coast of Southeast Asia, the Philippines are prone to typhoons and earthquakes, making Metro Manila ripe for storm surges. Metro Manila encompasses sixteen cities and is vulnerable to flooding on multiple accounts due to its location between two large bodies of water: Manila Bay to the west and Laguna de Bay to the southeast. Both of these bodies of water are subject to different types of flooding, such as “overbanking, storage-related floods, and interior floods.” (60) [5]

Figure 10. Metro Manila is a part of the Philippines that is prone to flooding because of the two bays surrounding it.
(Taken from www.islandsweb.net)

The Filipino government developed a plan for flood control in the 1990s, and the plan is looking to be revised in order to adequately address the problems of flooding. The Pasig-Marikina River (between the two cities Pasig and Marikina) is responsible for flooding in both cities, and is a center of interest in adaptation measures. A plan was proposed to construct basin embankments and a dam along the river, a move that would “almost eliminate floods in the Pasig-Marikina river basin” (66).[5]
Another developed plan is to improve pumping capacity in the area. The plan is to invest in better pumping capacity to reduce flood waters to the “allowable inundation depth of 30cm” in order to allow for transportation to occur (66).[5] Also considered is raising the height of storm surge barriers in coastal areas to “prevent overflow from Manila Bay caused by typhoons” (66).[5] These measures would collectively allow the public transportation systems optimal performance during oppressive weather in order to serve Filipino citizens.

How is Metro Manila adapting their transportation system to these floods and storms? In 2009, flash floods rendered Metro Manila’s thoroughfares “impassable to vehicular traffic” (28). [6] Despite “unavoidable congestion,” the Light Rail Transit and Metro Rail Transit (LRT and MRT, respectively) were able to accommodate passengers and offer an alternate route home. LRT Lines 1 and 2 were able to run “efficiently and without disruption” and in order to better aid commuters, passengers were offered a reduced fare and the number of running trains were nearly doubled (28). [6] In a time of crisis, the railway systems were able to operate as optimally as possible in order to facilitate transit despite the dicey weather conditions.