Leroy N. Soetoro
2023-06-02 21:56:48 UTC
https://www.bbc.com/future/article/20230523-new-yorks-skyscrapers-are-
causing-it-to-sink-what-can-be-done-about-it?utm_source=bbc-
news&utm_medium=right-hand-slot
The ground under New York City is sinking partly due to the sheer mass of
all its buildings and it isn't the only coastal city to be suffering
this fate. As sea levels also rise to meet these concrete jungles, can
they be saved?
O
On 27 September 1889, workers put the finishing touches to the Tower
Building. It was an 11-storey building that, thanks to its steel skeleton
structure, is thought of as New York City's first skyscraper. The Tower
Building is long gone its plum spot on Broadway was taken in 1914 but
its erection marked the beginning of a construction spree that still has
not stopped.
On the 300sq miles (777sq km) that comprise New York City sit 762 million
tonnes (1.68 trillion pounds) of concrete, glass and steel, according to
estimates by researchers at the United States Geological Survey (USGS).
While that figure involves some generalisations about constriction
materials, that prodigious tonnage does not include the fixtures, fittings
and furniture inside those million-odd buildings. Nor does it include the
transport infrastructure that connects them, nor the 8.5 million people
who inhabit them.
All that weight is having an extraordinary effect on the land on which it
is built. That ground, according to a study published in May, is sinking
by 1-2mm (0.04-0.08in) per year, partly due to the pressure exerted on it
by the city buildings above. And that is concerning experts add the
subsidence of the land to the rising of sea levels, and the relative sea
level rise is 3-4mm (0.12-0.16in) per year. That may not sound like much,
but over a few years it adds up to significant problems for a coastal
city.
New York has already been suffering subsidence since the end of last ice
age. Relieved of the weight of ice sheets, some land on the Eastern
Seaboard is expanding, while other parts of the coastal landmass,
including the chunk on which New York City lies, seem to be settling down.
"That relaxation causes subsidence," says Tom Parsons, a research
geophysicist at the Pacific Coastal and Marine Science Center of the USGS
in Moffett Field, California and one of the four authors of the study.
But the enormous weight of the city's built environment worsens this
subsidence, Parsons says.
And this is a global phenomenon. New York City, says Parsons, "can be seen
as a proxy for other coastal cities in the US and the world that have
growing populations from people migrating to them, that have associated
urbanisation, and that face rising seas".
There is a wide range of reasons for why coastal cities are sinking, but
the mass of human infrastructure pressing down on the land is playing a
role. The scale of this infrastructure is vast: in 2020 the mass of human-
made objects surpassed that of all living biomass. (Learn more about how
concrete has become the material that defines our age.)
Can anything be done to halt these cities which between them have
hundreds of millions of residents from sinking into the sea?
Some cities around the world such as Jakarta, capital of Indonesia are
sinking far faster than others. "In some cities, we're seeing subsidence
of a few centimetres a year," says Steven D'Hondt, professor of
oceanography at the University of Rhode Island in Narragansett. At this
rate, the city is sinking far faster than sea levels are rising to meet
it. "We'd have to increase ice melt by an order of magnitude to match
that."
As well as being a co-author on the New York study, D'Hondt is one of
three authors of a 2022 study that used satellite images to measure
subsidence rates in 99 coastal cities around the world. "If subsidence
continues at recent rates, these cities will be challenged by severe flood
events much sooner than projected," wrote D'Hondt and his colleagues Pei-
Chin Wu and Matt Wei, who are both at the University of Rhode Island.
Southeast Asia featured heavily in the list of cities suffering the most
rapid subsidence. Parts of Jakarta are subsiding at between 2cmm-5cm (0.8-
2in) per year. Alongside Jakarta, which is being replaced as Indonesia's
capital by a city being constructed 1,240 miles (1996km) away, were Manila
(Philippines), Chittagong (Bangladesh), Karachi (Pakistan) and Tianjin
(China). These cities are already suffering infrastructure damage and
frequent flooding.
Meanwhile, although it is not on the coast, Mexico City is sinking at an
astonishing 50cm (20in) a year thanks to the Spanish draining its
underlying aquifers when they occupied it as a colony. Research has
suggested it could take another 150 years before that sinking halts and
round 30m (98ft) of additional subsidence.
You might also like:
Will Venice succumb to the sea?
The Hong Kong approach to skyscrapers
What 1.5C living actually looks like
But it's the coastal cities that are the focus of the study by D'Hondt and
his colleagues. A large portion of Semarang in Indonesia, for example, is
sinking at 2-3cm (0.8-1.2in) per year while a significant area in the
north of Tampa Bay, Florida, is subsiding at 6mm (0.2in) annually.
Some level of this subsidence happens naturally, Wei says. However, it can
be greatly accelerated by humans not only by the load of our buildings,
but by our extraction of groundwater and our production of deep-lying oil
and gas. The relative contribution of each of these phenomena, says Wei,
"vary from place to place, making it a challenging task to understand and
address coastal subsidence".
But address it we must. Rising water causes damage well before it starts
crashing over flood barriers: it is a rising tide that sinks all boats.
The first effects of a relative rise in sea level, says D'Hondt, take
place below the surface. "You've got buried utility lines, buried
infrastructure, buried foundations for buildings, and then, the seawater
starts working with that stuff long before you see it above ground." As
this goes on, storms bring water ever further into cities.
The solutions vary according to the local causes of subsidence.
One obvious approach, albeit one that comes with its own problems, is to
stop building. As Parsons explains, the settling of the ground beneath
buildings "is generally complete a year or two after construction".
Although much of New York City has bedrock of schist, marble and gneiss,
these rocks have a degree of elasticity and fractures in them that account
for some of the subsidence. But the clay-rich soil and artificial fill
materials that are particularly prevalent in lower Manhattan can cause
some of the largest amounts of subsidence, says Parsons and his
colleagues. So ensuring the largest buildings are positioned on the most
solid bedrock could help to reduce the downward trend.
Another solution, at least for some places, is to slow the withdrawal of
groundwater and extraction from underground aquifers. Parsons and his
colleagues warn that increasing urbanisation will likely increase the
amount of groundwater being extracted and combine with even more
construction to cope with the growing population. Finding more sustainable
ways of supplying the city's water needs and maintaining groundwater
levels could help.
However, the most common approach is a messy and imperfect programme of
constructing and maintaining flood defences such as sea walls. Tokyo's
adaptation to land subsidence is two-pronged. The city has built physical
structures like concrete dykes, seawalls, pump stations and flood gates.
These are combined with social measures like evacuation rehearsals and an
early-warning system.
Some level of this subsidence happens naturally, but it can be greatly
accelerated by humans not only by the load of our buildings, but by our
extraction of groundwater and our production of deep-lying oil and gas
Sometimes it is residents themselves who step in. A 2021 study documented
how residents of Jakarta, Manila and Ho Chi Minh City have taken their
own, informal measures. These include raising floors, moving household
appliances and, in Manila, building makeshift bridges between houses in
swampy areas.
Other useful tools include attenuation tanks: large tanks that sit
underground and release stormwater at a controlled, slow rate. Martin
Lambley, a drainage expert at the pipe manufacturing company Wavin, says
that attenuation tanks should be combined with natural elements like
ponds, soakaways (rubbly pits from which water drains slowly) and swales
(marshy basins). "The challenges we face today differ drastically from
when urban sewers and drainage systems were first introduced," he says.
We might see more innovative solutions as the waters rise. In 2019, the UN
held a roundtable discussion on floating cities, which might take the form
of pontoon structures. Finally, stopping climate change by eliminating
greenhouse gas emissions would prevent or delay at least some melting of
the polar ice caps, slowing sea level rise.
"I think that governments need to be concerned," says D'Hondt. "If they
don't want to have massive loss of infrastructure and economic capacity in
a few decades, they need to start planning right now."
--
We live in a time where intelligent people are being silenced so that
stupid people won't be offended.
Durham Report: The FBI has an integrity problem. It has none.
No collusion - Special Counsel Robert Swan Mueller III, March 2019.
Officially made Nancy Pelosi a two-time impeachment loser.
Thank you for cleaning up the disaster of the 2008-2017 Obama / Biden
fiasco, President Trump.
Under Barack Obama's leadership, the United States of America became the
The World According To Garp. Obama sold out heterosexuals for Hollywood
queer liberal democrat donors.
President Trump boosted the economy, reduced illegal invasions, appointed
dozens of judges and three SCOTUS justices.
causing-it-to-sink-what-can-be-done-about-it?utm_source=bbc-
news&utm_medium=right-hand-slot
The ground under New York City is sinking partly due to the sheer mass of
all its buildings and it isn't the only coastal city to be suffering
this fate. As sea levels also rise to meet these concrete jungles, can
they be saved?
O
On 27 September 1889, workers put the finishing touches to the Tower
Building. It was an 11-storey building that, thanks to its steel skeleton
structure, is thought of as New York City's first skyscraper. The Tower
Building is long gone its plum spot on Broadway was taken in 1914 but
its erection marked the beginning of a construction spree that still has
not stopped.
On the 300sq miles (777sq km) that comprise New York City sit 762 million
tonnes (1.68 trillion pounds) of concrete, glass and steel, according to
estimates by researchers at the United States Geological Survey (USGS).
While that figure involves some generalisations about constriction
materials, that prodigious tonnage does not include the fixtures, fittings
and furniture inside those million-odd buildings. Nor does it include the
transport infrastructure that connects them, nor the 8.5 million people
who inhabit them.
All that weight is having an extraordinary effect on the land on which it
is built. That ground, according to a study published in May, is sinking
by 1-2mm (0.04-0.08in) per year, partly due to the pressure exerted on it
by the city buildings above. And that is concerning experts add the
subsidence of the land to the rising of sea levels, and the relative sea
level rise is 3-4mm (0.12-0.16in) per year. That may not sound like much,
but over a few years it adds up to significant problems for a coastal
city.
New York has already been suffering subsidence since the end of last ice
age. Relieved of the weight of ice sheets, some land on the Eastern
Seaboard is expanding, while other parts of the coastal landmass,
including the chunk on which New York City lies, seem to be settling down.
"That relaxation causes subsidence," says Tom Parsons, a research
geophysicist at the Pacific Coastal and Marine Science Center of the USGS
in Moffett Field, California and one of the four authors of the study.
But the enormous weight of the city's built environment worsens this
subsidence, Parsons says.
And this is a global phenomenon. New York City, says Parsons, "can be seen
as a proxy for other coastal cities in the US and the world that have
growing populations from people migrating to them, that have associated
urbanisation, and that face rising seas".
There is a wide range of reasons for why coastal cities are sinking, but
the mass of human infrastructure pressing down on the land is playing a
role. The scale of this infrastructure is vast: in 2020 the mass of human-
made objects surpassed that of all living biomass. (Learn more about how
concrete has become the material that defines our age.)
Can anything be done to halt these cities which between them have
hundreds of millions of residents from sinking into the sea?
Some cities around the world such as Jakarta, capital of Indonesia are
sinking far faster than others. "In some cities, we're seeing subsidence
of a few centimetres a year," says Steven D'Hondt, professor of
oceanography at the University of Rhode Island in Narragansett. At this
rate, the city is sinking far faster than sea levels are rising to meet
it. "We'd have to increase ice melt by an order of magnitude to match
that."
As well as being a co-author on the New York study, D'Hondt is one of
three authors of a 2022 study that used satellite images to measure
subsidence rates in 99 coastal cities around the world. "If subsidence
continues at recent rates, these cities will be challenged by severe flood
events much sooner than projected," wrote D'Hondt and his colleagues Pei-
Chin Wu and Matt Wei, who are both at the University of Rhode Island.
Southeast Asia featured heavily in the list of cities suffering the most
rapid subsidence. Parts of Jakarta are subsiding at between 2cmm-5cm (0.8-
2in) per year. Alongside Jakarta, which is being replaced as Indonesia's
capital by a city being constructed 1,240 miles (1996km) away, were Manila
(Philippines), Chittagong (Bangladesh), Karachi (Pakistan) and Tianjin
(China). These cities are already suffering infrastructure damage and
frequent flooding.
Meanwhile, although it is not on the coast, Mexico City is sinking at an
astonishing 50cm (20in) a year thanks to the Spanish draining its
underlying aquifers when they occupied it as a colony. Research has
suggested it could take another 150 years before that sinking halts and
round 30m (98ft) of additional subsidence.
You might also like:
Will Venice succumb to the sea?
The Hong Kong approach to skyscrapers
What 1.5C living actually looks like
But it's the coastal cities that are the focus of the study by D'Hondt and
his colleagues. A large portion of Semarang in Indonesia, for example, is
sinking at 2-3cm (0.8-1.2in) per year while a significant area in the
north of Tampa Bay, Florida, is subsiding at 6mm (0.2in) annually.
Some level of this subsidence happens naturally, Wei says. However, it can
be greatly accelerated by humans not only by the load of our buildings,
but by our extraction of groundwater and our production of deep-lying oil
and gas. The relative contribution of each of these phenomena, says Wei,
"vary from place to place, making it a challenging task to understand and
address coastal subsidence".
But address it we must. Rising water causes damage well before it starts
crashing over flood barriers: it is a rising tide that sinks all boats.
The first effects of a relative rise in sea level, says D'Hondt, take
place below the surface. "You've got buried utility lines, buried
infrastructure, buried foundations for buildings, and then, the seawater
starts working with that stuff long before you see it above ground." As
this goes on, storms bring water ever further into cities.
The solutions vary according to the local causes of subsidence.
One obvious approach, albeit one that comes with its own problems, is to
stop building. As Parsons explains, the settling of the ground beneath
buildings "is generally complete a year or two after construction".
Although much of New York City has bedrock of schist, marble and gneiss,
these rocks have a degree of elasticity and fractures in them that account
for some of the subsidence. But the clay-rich soil and artificial fill
materials that are particularly prevalent in lower Manhattan can cause
some of the largest amounts of subsidence, says Parsons and his
colleagues. So ensuring the largest buildings are positioned on the most
solid bedrock could help to reduce the downward trend.
Another solution, at least for some places, is to slow the withdrawal of
groundwater and extraction from underground aquifers. Parsons and his
colleagues warn that increasing urbanisation will likely increase the
amount of groundwater being extracted and combine with even more
construction to cope with the growing population. Finding more sustainable
ways of supplying the city's water needs and maintaining groundwater
levels could help.
However, the most common approach is a messy and imperfect programme of
constructing and maintaining flood defences such as sea walls. Tokyo's
adaptation to land subsidence is two-pronged. The city has built physical
structures like concrete dykes, seawalls, pump stations and flood gates.
These are combined with social measures like evacuation rehearsals and an
early-warning system.
Some level of this subsidence happens naturally, but it can be greatly
accelerated by humans not only by the load of our buildings, but by our
extraction of groundwater and our production of deep-lying oil and gas
Sometimes it is residents themselves who step in. A 2021 study documented
how residents of Jakarta, Manila and Ho Chi Minh City have taken their
own, informal measures. These include raising floors, moving household
appliances and, in Manila, building makeshift bridges between houses in
swampy areas.
Other useful tools include attenuation tanks: large tanks that sit
underground and release stormwater at a controlled, slow rate. Martin
Lambley, a drainage expert at the pipe manufacturing company Wavin, says
that attenuation tanks should be combined with natural elements like
ponds, soakaways (rubbly pits from which water drains slowly) and swales
(marshy basins). "The challenges we face today differ drastically from
when urban sewers and drainage systems were first introduced," he says.
We might see more innovative solutions as the waters rise. In 2019, the UN
held a roundtable discussion on floating cities, which might take the form
of pontoon structures. Finally, stopping climate change by eliminating
greenhouse gas emissions would prevent or delay at least some melting of
the polar ice caps, slowing sea level rise.
"I think that governments need to be concerned," says D'Hondt. "If they
don't want to have massive loss of infrastructure and economic capacity in
a few decades, they need to start planning right now."
--
We live in a time where intelligent people are being silenced so that
stupid people won't be offended.
Durham Report: The FBI has an integrity problem. It has none.
No collusion - Special Counsel Robert Swan Mueller III, March 2019.
Officially made Nancy Pelosi a two-time impeachment loser.
Thank you for cleaning up the disaster of the 2008-2017 Obama / Biden
fiasco, President Trump.
Under Barack Obama's leadership, the United States of America became the
The World According To Garp. Obama sold out heterosexuals for Hollywood
queer liberal democrat donors.
President Trump boosted the economy, reduced illegal invasions, appointed
dozens of judges and three SCOTUS justices.