We are constantly reminded that climate
change will alter life on Earth as we know it, but people seem to go
about their daily lives as if nothing is wrong. According to a report
from the Washington Post,
a new study aims to change that by bringing things a little closer to
home. In the report, climates scientists warn that New York City is at a
severe risk of storm-surge flooding.
The risk is significantly higher than it was 1000 and even 100 years
ago. The report states that the increased risk of flooding is not only
due to sea level rise, but to the increased intensity of coastal storms
that often hit the Big Apple.
The researchers explained that they were seeing more intense storms
that had a much easier time thrusting ocean water towards the land,
citing The Battery as one of the NYC neighborhoods that has taken the
biggest pounding from the ocean.
The paper was published in The Proceedings of the National Academy of Sciences
by Andra Reed from Penn State University in conjunction with a group of
other researchers including Reed’s colleague Michael Mann, MIT
hurricane expert Kerry Emanuel, and Princeton’s Ning Lin. Emmanuel and
Lin released a separate study earlier this September outlining the risks
faced by Tampa, FL from the same types of intensified coastal storms.
The Atlantic Ocean is known for keeping hurricane damage to the
coasts at a minimum, at least as far as records dating back to 1851 say.
In reality, this time frame is too short to say if the risks to New
York City’s coastal areas have significantly increased since before
records started being taken, but the trends affecting the city line up
with other trends in coastal regions around the world.
The research team attempted to make the best possible estimate of
what hurricane records may have looked like from the years 850 to 1800
in the Atlantic Ocean. They simulate huge numbers of “downscaled”
Atlantic coast hurricanes over these years, and compared them to storm
surge records that were taken from hurricanes from 1970 to today, the
period scientists call the “anthropogenic era.”
The researchers discovered something important in their models. One
of the biggest variables that didn’t remain static was the level of the
ocean off of New York’s coast. Using geological records from over 1,000
years of past sea levels from nearby New Jersey’s shore on the Atlantic,
the synthetic storm surges modeled were each based off of the sea
level’s position when the storm occurred.
So what does all of this mean? Storms varied widely over the last
1000 years on the Atlantic coast. One of the key findings is that sea
levels are significantly higher than they were in 850 A.D. The sea
level’s ascent has accelerated sharply over the past 100 years, and
consequently, the average storm surge for hurricanes during the
anthropogenic era, since 1970, has risen by a factor of nearly 1.24
meters. According to the study, these results highlight the ever-growing
risk faced by coastal communities across the U.S. on account of rising
sea levels combined with increasingly intense storm surges.
One of the most poignant examples, still fresh in the memories of
countless residents living in New York City and up and down the northern
East Coast, is superstorm Sandy. Researchers estimate that a storm of
that intensity is so rare that it should only occur once every 3,000
years. With the changes to sea level and the increasing intensity of
coastal storms, however, storms of this magnitude are more likely to
show up at least once every century.
Rising sea levels pose the greatest risk. When climate studies refer
to the sea level rising by less than a meter in some places, it really
doesn’t seem like that big of a problem. You’re not even going to notice
a meter less beach on your next visit to the shore, right?
The real risk lies in the destructive power of water. Have you ever
tried to lift a full 10-gallon bucket? If you have, you will recall that
is extremely heavy. Now, imagine how many of those buckets you would
have to dump into the ocean to make the entire sea rise by just one
meter. That’s a lot of extra water.
The additional water, which is added through a combination of melting
ice from the polar regions and a phenomenon called thermal expansion,
wherein the water molecules are actually spread further apart due to
increased heat, has great destructive power. Combine this with the
powerful currents and winds produced by a hurricane, and you have a
recipe for disaster.
With higher waves traveling further inland during these storms, the
risk for property damage becomes much higher. We all watched in 2012 as
entire blocks of New York City were up to the trashcans in floodwater,
subways closed, and cars floated aimlessly towards the sea as the
streets drained. Billions of dollars of damage were caused up and down
the coast, and that risk is only poised to increase with future storms.
The researchers further coaxed out the real risk of storm surges from
their models due to changing sea levels. They did not find an average
difference in the height of storm surges between the
pre-and-post-anthropogenic eras, but a “long-tail” phenomenon that
showed severe surges becoming more common and worse than before. The
paper wrote, “The storm surge heights in the tails of the anthropogenic
distributions are significantly greater than the storm surge heights in
the tails of the pre-anthropogenic storm surge distributions.”
The researchers warn that the risk posed by future hurricanes will
likely mimic what we saw with Hurricane Sandy in 2012. Climate change,
they contend, is not something that we should be waiting for – we should
already be dealing with it now.
Source: BAWB News
Nenhum comentário:
Postar um comentário