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Sea Level Rising Faster Than Average In Northeastern U.S.

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Sea level is rising all over the world thanks to the heat-trapping effect of greenhouse-gas emissions, but according to a new study published in the Journal of Coastal Research, the northeastern U.S. and eastern Canada have seen the ocean rise at an accelerating rate in recent decades.

Based on readings at 23 tidal gauges stretching along the entire East Coast, John Boon of the Virginia Institute of Marine Science has determined that the rate of sea level rise began to accelerate in 1987 at points north of Norfolk, Va.

Considerable beach erosion at Surf City, New Jersey.
Credit: Jim Phillips

Boone concluded that if the acceleration continues at this rate — something that is not certain at this point — Boston will see 27 inches of sea-level rise by 2050, New York will see 20 inches and Norfolk will see 24 inches.

By contrast, Charleston, S.C., whose rate of sea level rise is closer to the worldwide average, will see less than 6 inches. (In all locations, the bulk of sea level rise will happen in the second half of the century, as warming temperatures continue to transfer more and more freshwater from the ice sheets in Greenland and Antarctica into the sea).

Scientists broadly agree that on a worldwide basis, sea level, already 8 inches higher than it was in 1900, is likely to go up by another 3 feet or so by the end of this century. That’s a global average. However, depending on local conditions, the change could be less in some areas, and greater, along with a greater threat to life and property, in others. The new study, which reinforces research published in Nature Climate Change last June, says that the northeastern U.S. falls into the “greater” category.

The increase was most evident at the eight stations with continuous records stretching back 75 years or more: Halifax, Nova Scotia; Portland, Maine; Boston; New York’s Battery; Sandy Hook and Atlantic City, N.J.; Baltimore, and Norfolk. Eight more stations in the same region, with records going back  43 years, also showed acceleration, although the speedup was less clear due to the shorter observation period.

Stations south of Norfolk, on the other hand, showed no acceleration. “Sea level is rising at these stations,” Boon said in a press release, “but there is no statistically significant acceleration in the rise rate during the period of record.”

The natural question, of course, is why this is happening? Boon offered no concrete answer, but suggested that it may have to do with a possible slowdown in the Gulf Stream as glacial meltwater dilutes the salty North Atlantic and weakens the circulation of warm water to toward the poles. That would make water pile up behind the slowdown, like traffic on a congested highway.

That’s not the only factor that affects local sea level. Another is the fact that some land is rising, still rebounding from the disappearance of the glaciers thousands of years ago, while other land is sinking. That’s one reason Norfolk’s projected sea level rise by 2050 is nearly as great as Boston’s: the Gulf Stream effect would be less in Virginia, but the land around Norfolk is sinking.

For people who are actually affected by rising seas and the increased coastal flooding they’re sure to bring, the overall exposure is what matters “My analysis focuses on relative sea level,” Boon said. “That value — the height of the sea surface in relation to the land, is what really matters to coastal communities.”

And if heat-trapping greenhouse gases continue to build in the atmosphere, that height is just going to keep going up.

Related content
How a Patch of Ocean Helps Keep Europe from Freezing
Climate and Carbon: The Link Just Got Stronger
The Secret of Sea Level Rise: It Will Vary Greatly by Region

Comments

By Paul Stone (Beach Haven, NJ 08008)
on October 18th, 2012

I have some waterfront properity on LBI….CHEAP!!

Reply to this comment

By Jeff MacLeod
on October 18th, 2012

I think in order to not sew confusion in the minds of those that deny climate change or sea level rise we shouldn’t say “sea level is rising all over the world” but instead say “The average sea level worldwide is increasing”. In many areas of the world sea level is falling while in others it is rising at different rates. Of course this is due to many various factors such as gravitational changes from melting sea ice, isostatic rebound, and so on.

http://tidesandcurrents.noaa.gov/sltrends/sltrends.shtml

Reply to this comment

By Wolf Heinl (Pittsburgh, PA 15010)
on October 18th, 2012

A slow down in the arctic current has already been measured a few years ago.  If this acceleration of the rate of SLR is due to this slow down, things are worse than what I thought.  And, that’s pretty bad.

Why isn’t anyone (including the politicians) talking about this?  This is really urgent.

Reply to this comment

By dan in illinois
on October 19th, 2012

Jeff,

As a man-made-climate change denier, I assure you that I am not confused.  Very little of these phenomena are well understood by these so-called experts and, as a result, virtually none of it can be predicted.

Reply to this comment

By Phil (Alberta)
on October 20th, 2012

Dan,
It’s quite a simple phenomenon that causes sea level rise, the addition of water that was previously on land being added to the sea increases the sea level, this is analogous to adding a small bucket of water to a full bathtub - the level rises. Secondly, the more important effect, and one is explained by thermodynamics, is the thermal expansion of water. The oceans absorb a lot of heat, but there is a lag due to high specific heat capacity of water, so for the later 100 years or so any heat caused by an enhanced greenhouse effect has been absorbed by the oceans, this is why it has taken time to see changes in air temperature, whilst there has been small (on a global scale) sea level rise at the same time.
Now, as we proceed with business as usual, the added lag of CO2, (most of) which stays in the atmosphere as a greenhouse gas for 30-40 years, adds enhances the warming effect for decades, increasing the rate of change in temperature as more CO2 is produced (via increased wildfires, human emissions, etc).

So it is conceivable that sea levels will continue to rise in the coming decades, no model is 100% accurate, just look at weather forecasts - we’ve been doing it for decades and its not always right, there is a chaotic element to the system that we cannot account for. However, its extremely likely that sea levels will (continue to) rise, the question of how much is predictable, but we are most likely to under-predict the quantity because of the lack of complexity that can be put into any model - even with today’s supercomputers.

Reply to this comment

By michael murphy (Oakdale/CT/06370)
on October 22nd, 2012

As a city planner, this is a topic I feel needs to be incorporated into the mainstream of planning.Smart cities will take an approach that recognizes this threat to our assets( homes,infrastructure, marshes,etc.) and start to plan for , or at least anticpate,it. Writers and opinions on both sides need to be concerned with this rate of slr accelleration,  but should not underreact or overreact to what is being seen. This will take anticipation and monitoring over defined horizons, say 10 year intervals,and developiment of scenarios to address uncertain events. Politicians and policy makers that do not begin to talk about it to their populations, or fail to perform vulnerability assessments, risk lack of planning for economic impacts…that neither their state or federal governments can be expected to resolve…or pay for.

Reply to this comment

By peter (boston/ma/02215)
on November 1st, 2012

The sea level is not rising. It is the land level that is falling.

Reply to this comment

By John (Hermitage/TN/37076)
on November 20th, 2012

The earth and all its fluids from seawater to the air at the peak of Everest is increasing in temperature. That is not in question. The question is whether it is caused by the activities of man, exacerbated by the activities of man or whether the portion that is man-caused is significant at all.
Some 15,000 years ago, the earth started to warm up from an ice age. It has been doing so at a relatively constant rate for that period, with peaks and valleys in the rate of increase but none significantly point to man-caused effects.
Mars is warming at a rate, when corrected for the inverse-square law for the propagation of light (infra-red), compares closely with what we see here. You also have to take into account the greater eccentricity of Mars’ orbit. Do the math, though, and you see near identical (adjusted) heating rates.
Glaciers extended far south into what are now temperate areas of the earth during the Ice Age. That fresh water went into the seas and caused the levels to rise. The glacier retreat in the >14000 years since the end of that age dwarfs than since mankind experienced a significant amount of industry.
Wast Anglia has been proven false. Gaia is the goddess of the cult of the beautiful people (and Ralph Nader, who ain’t). Let it go. We can’t do anything to make it cooler but turn down the thermostats in summer.

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