the world seas are rising. Fed by human warming, the great waters
have been pushed to thermally expand. The added heat is melting the
glaciers as well. And from the high mountains to the Arctic and on
into the Antarctic there are few ice masses now that have been
untouched by the rising temperatures.
rise in ocean heights began as human fossil fuel emissions spread
into the airs of the early 20th Century — warming both the
atmosphere and the waters. The rate of rise was, at first, slow —
less than 1 mm per year. But as the greenhouse gasses built up and
rates of global heating increased, so did the annual rate of sea
level rise. By the end of the 20th Century, sea level rise had more
than tripled to about 2.9 mm per year. And by today that annual rate
of increase has accelerated to nearly 3.4 mm per year.
sea level rise graph shows rate of ocean rise again increasing in the
2010 to 2016 timeframe. It is very likely that glacial
destabilization will result in ever-more-rapidly rising ocean waters
as the 21st Century progresses. Image source: AVISO.)
slow sea level rise rates during the 20th Century were manageable.
Coastal communities were mostly built on high enough ground to give
them some protective margin against the gradually rising tides. But
now, for many cities along the US coast and upon its bays and
estuaries, a kind of tipping point has been reached. Where it took a
moderate-to-strong storm to generate flooding in the past, now only a
high tide and a bit of onshore wind will suffice.
issue is not just a problem for places like Miami and South Florida
or New Orleans and the Louisiana Delta. It’s a problem for the
entire coastline. And though the lowest-lying areas were affected
first, more and more regions are starting to fall below the line of
the rising tide.
Seasonal High Tide Now is Enough to Flood Atlantic City
was the situation today in Atlantic City, New Jersey. There, a weak
off-shore low pressure system pushed an equally weak wind toward
shore. The meager flux of water driven by this mild fetch combined
with a seasonal high tide. Together, these entirely normal events
were enough to flood streets throughout Atlantic City.
avenue floods this morning in Atlantic City. By evening, water
levels are expected to have risen even higher. Image source: City
flooding was extreme enough to cause road closures and to spark a
flurry of social media comments on Twitter. Particularly hard-hit
were the neighborhoods of West End and North Wildwood. To be very
clear, this is no hurricane, no Superstorm Sandy, just a normal high
tide riding on the back of an entirely abnormal sea level rise due to
human-caused climate change.
kind of flooding is not enough to cause major damage. But it is cause
for concern. For now, Atlantic City is far more vulnerable to storms
and to flooding than it has ever been in the past. And with human
warming due to fossil fuel burning continuing to push seas higher,
Atlantic City, like so many other US Coastal communities will, sooner
or later, face the threat of total inundation.
Could be Lost by 2030 to 2050, Unlikely to Remain Viable to 2100
in the far south, the glaciers of Antarctica are starting to rapidly
destabilize. And, in the north, Greenland melt is also rapidly
accelerating. Due to the way gravity affects the world’s oceans,
Antarctic melt will have the greatest effect on base sea level rise
in the North Atlantic. Meanwhile, Greenland melt risks backing up the
Gulf Stream and contributing to up to 3 feet of additional sea level
rise on the US East Coast as water rebounds toward shore.
sea level rise scenarios as envisioned by a recent Rutgers study. A
number of scientists, including Dr. James Hansen, points to even more
extreme potentials. Image source: Sea
Level Rise in New Jersey Fact Sheet.)
as soon as 2030, seas could be as much as 1.4 feet higher than they
are today in the Atlantic City region. And if the worst case scenario
that scientists like James Hansen have warned us about come to pass,
then by 2100 seas will have completely covered Atlantic City with a
multimeter ocean rise. Put in context, by 2030 seasonal tidal
flooding seen today is likely to become monthly tidal flooding by
2030. And between 2030 and 2050, such flooding will become a daily
event rending most infrastructure useless and likely resulting in a
complete loss of the City’s ability to function.
even before then, one large storm may complete what hundreds of tides
would eventually accomplish. For garden variety nor’easters will
grow more and more capable of producing the kind of catastrophic
flooding seen during Superstorm Sandy as the years progress.
probably true that we’ve already burned enough fossil fuels to
generate sea levels high enough to inundate many cities near or on
the coastline. But continuing to burn fossil fuels makes the
situation worse and far more immediate. Stopping that continued bleed
of heat trapping gasses into the Earth’s atmosphere gives
communities like Atlantic City a chance — if not to survive
long-term against an inevitably rising tide, then to figure out a way
to orderly retreat inland and to at least preserve some of the
heritage that is now falling under threat from the inexorably rising
waters. And such a necessary cessation would give communities still
further inland a reasonable hope that they, unlike Atlantic City,
will not share the fate of Atlantis.