Sea level rise is accelerating in the northeast

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“Global sea level rise from ice melting and ocean warming from 1900 to 2000 has led to a rate that is more than twice the average for the years 0-1800 – the most significant change,” Rutgers said of the study’s findings.

The study uses new techniques and focuses on six specific locations in the Northeastern United States, including three in New Jersey and one each in Connecticut, New York and North Carolina.

Man-made climate change fuels this more dramatic growth. Research shows that emissions of carbon dioxide and other greenhouse gases from people burning fossil fuels have warmed our planet, causing the oceans to heat up and glaciers to melt.

This research is the first of its kind to use what researchers call “sea-level budgets”, while determining the rate at which the ocean grows over an extended period.

A sea level budget examines sea level change over time on a global, regional and local scale. It breaks down how sea level is affected by various phenomena, which are divided into scales. At each of these scales, there are different factors that contribute to rising water levels or, in some cases, lowering the level.

On a global scale, for example, factors such as water temperature play a role, while on a local scale, the budget may take into account land subsidence, which may vary by city.

“If you want to know what causes sea level change, this budget approach is a way to break down these individual components,” said Jennifer Walker, lead author of the study and a postdoctoral researcher at Rutgers University.

What this research found is that the increase in levels in these locations succeeds in any decrease in the period examined.

“Regional submersion has been the dominant component of sea level change over those long periods of time,” Walker said.

Sea level rise is rising fastest in populated coastal areas, the study says
The study found that southern New Jersey had the largest sea level rise in 2,000 years due to landslides.

This landslide “is due to the effect of the Laurentide ice sheet from our last ice age,” Walker told CNN. “The ice sheet receded thousands of years ago, and the earth is readjusting as a result of that layer of the past.”

There are also other factors, which include the extraction of groundwater and changing ocean currents.

“US East Coast sea level rise rates are rising due to the slowdown in the Gulf Stream,” said Brian McNoldy, senior research associate at the University of Miami Rosenstiel School of Marine and Atmospheric Sciences, which was not part of study.

Walker added that in the last 200 years or so, “We have rates that are double the average compared to the last 2,000 years … Where this regional landslide was the dominant force, now is this global component , which is driven by melting ice and warming the oceans. “

These graphs show sea level rise rates over time from each sea level budget. Light gray resembles the most dominant, linear budget. This category concerns the fall of the land caused by the natural compaction of the land and the melting of the Laurentide ice sheet. The pie charts also show how the linear sea level budget is the largest component of sea level rise in New Jersey. The other shades in the graphs mean the other three budgets at sea level: global (red), nonlinear regional (light blue) and local (purple). The black dotted line on the graphs shows the total rise in sea level when combining these four budgets.
At this global scale, sea level rise was found to be primarily caused by “increasing ocean mass and volume since melting glaciers and ice sheet and global thermal expansion in response to greenhouse temperature forcing. sea ​​surface and surface air ‘. says the research.

While sea level budgets have increased at least in the last century, some have decreased over time. Before about 1600 AD, the non-linear regional budget had a declining sea level. This drop in sea level is likely to be caused by “wide climate transitions in the North Atlantic”, according to research. This includes pressure patterns across the North Atlantic, which is practically where the low and high pressure systems are located.

Climate change is accelerating rates

These global factors did not make a dominant contribution to sea level rise before 1800, but this has changed recently. “The growing influence of the global component is the most significant change in sea budgets at all six sites,” according to the study.

This means that humans cause the sea to rise and dominate the Earth’s systems, scientists say.

Data collected for a location in northern New Jersey shows that between 1400 and 1500 AD, the sea level of the global budget probably increased at a rate of 0.13 millimeters per year. A few hundred years later, between 1900 and 2000 or the twentieth century, the rate rose sharply to 1.30 millimeters per year.

Meanwhile, regional and local budgets at sea level have either been constant or have undergone significantly smaller changes.

On a global scale, for example, there have been sea level rises over several centuries, but then they are declining. This is a natural cycle. But what happened recently in the twentieth century was not completely natural due to a more significant, upward acceleration in water levels.

Walker said sea level rise trends may be related to already emitted greenhouse gases and that rates will continue to accelerate.

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This acceleration will increase the number of days per year of floods, sometimes known as sunny day floods. Tidal cycles can play a role in this, including the high tide in the fall, which produces the highest tidal levels of the year. Combine this with the rising sea and this will lead to more days of coastal flooding, regardless of the weather.

There is another component of how rising sea levels can have a big impact: big storms. Walker remarked, “With these big storm events, you can really see the impact more.”

A storm like Hurricane Sandy in 2012 damaged much of the Northeast, including New York City, with a record wave of storms. “The impacts of such a big storm will be exacerbated above (the rising sea).”

Walker said the effects of rising sea levels during significant weather events are a longer-term challenge as levels rise further.

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