Bar Harbor Sea Level Rise: Key Findings and Implications

First, it will look at the data.

Mar 20, 2026

Three people standing on a wooden boardwalk overlooking a lush green marshland under a partly cloudy sky. One person is kneeling and pointing towards the landscape.

BAR HARBOR— For Ella Boxwell, a graduate student at UMA, the data made it obvious that it’s happening: the sea level in Bar Harbor has increased 16 centimeters since 1947.

From today until 2055, she projects it to raise another 16-20 centimeters.

“We are in a bit of an accelerated trend,” she told members of the Bar Harbor Harbor Committee last week.

This is important because the town’s land use ordinance that dictates things such as maximum pier length doesn’t take into account changing averages of high and low tides and how that might damage a pier, a road, a shore path, a business, a home.

Boxwell’s findings may be used to update the town’s land use ordinance, be used by committees like the Harbor Committee or the town’s Task Force on the Climate Emergency or even its public works and harbor departments. It can also be used for property owners to understand risks and opportunities at their own properties.

Those include properties like the Oceanarium and Education Center, which is located adjacent to Jones Marsh at the head of the island, in Bar Harbor.

“When we first even looked at the property, there was water in the parking lot,” owner Jeff Cumming said in 2024. “It was obvious.”

They bought it anyway. His three girls loved the trails, the site. He couldn’t stand driving by, year after year, and seeing the beautiful property vacant.

During the December 2022 storm just before Christmas, two of the buildings flooded. One filled with eight to nine inches of water. About 12 inches of water infiltrated the other.

The questions became, he said, “how do we deal with it and how do we make use of it?”

Because of where the Oceanarium is situated in salty tidal marshes, “the entire campus is a sea-level-rise exhibit,” Cumming said.

Line graph showing annual mean sea level at Bar Harbor from 1948 to 2020, with data points increasing over time. — Via Landscape of Change

“We can expect about 16 centimeters of sea level rise from today up to 2055,” Boxall told the committee members who attended the meeting, which did not have a quorum, so no action was taken.

There are other implications to her research, too.

You can’t drive over Route 3 if parts of it are flooded.

You probably don’t want to build homes in a place that’s going to be partially underwater.

You probably want to shore up the current infrastructure or find ways to mitigate houses, roads, and businesses in flood-risk areas.

Graph showing sea level trends over time with three projection lines: polynomial of degree 3, linear projection, and yearly moving average. The vertical axis represents sea level in meters, while the horizontal axis represents time.

Bar graph showing total hours per year above king tide threshold from 1950 to 2023, indicating an increase in hours over time due to sea level rise. — Via Boxall’s presentation

“I used hourly tidal station data from Bar Harbor collected by NOAA from 1947-2025,” Boxwell explained.

The trends previously found by Maine Geological Survey are somewhat similar to Boxwell’s conclusion. The rate of rise is 5.32 mm per year since 2000, and 2.45 mm per year prior to 2000.

She also plotted the total hours the sea was above the king tide level. That has also increased over time.

“It’s more from the fact that our water level is higher over time,” she said as the reason.

According to the National Ocean Service, National Oceanic and Atmospheric Administration (NOAA), “a king tide is a non-scientific term people often use to describe exceptionally high tides. Tides are long-period waves that roll around the planet as the ocean is ‘pulled’ back and forth by the gravitational pull of the moon and the sun as these bodies interact with the Earth in their monthly and yearly orbits. Higher than normal tides typically occur during a new or full moon and when the Moon is at its perigee, or during specific seasons around the country.”

It is basically, the highest tide or tides of the year.

The king tides also give people a preview of where the future regular average day’s high tide will be. They show a community where sea level rise is going to make an impact. They show a community where it is going to have to try to tweak or change infrastructure to deal with that impact. They show a community what its future might look like.

A wooden wall featuring painted wave patterns and the years '2100' in blue and '2024' in white. — An actual tide mark on an oceanarium building in 2024, projected in 2100. File photo.

In the 1980s, there were a lot of storms, which Boxall believes caused a lot of peaks in that king tide level both here and in Portland.

“Portland was on a similar trend as Bar Harbor,” she said.

Boxall has been collecting hourly tide data from Bar Harbor and created a yearly tide average for every hour rather than using one data point per year, which allowed for more precise data and projects than an earlier Maine survey, she believes.

She used the MATLAB curvefitter tool, which minimizes the errors between models and observations.

“I found that we actually were spending fewer hours below the level of very low tides over time. You can see it was very frequent up until like 1970, when it started to decline pretty quickly,” Boxall said. “And since—I think that’s 2022—we haven’t actually had any hours below that threshold. I use the same metric as the king tide metric, so it’s below its 95% of tides, and it just goes to show it’s probably not because of something tidal that you’re experiencing (this). It’s more like more exposed beach, but it could be due to something like sediment transport, and that was my thought, just from my civil engineering perspective on what that could have potentially been.”

A man sitting in an Adirondack chair beneath a canopy, looking toward a wooden shed and grassy area, with a picnic table visible in the background. — Jeff Cumming in the Oceanarium’s picnic area. Behind him stenciled on the building is the high water mark from the December 2022 storm. Above, a marsh by the Oceanarium and Route 3 near the head of Mount Desert Island shows one prediction of the anticipated water level events for 2050. File photos: Carrie Jones/BHS.

“Ella has been doing a lot of great work for us, especially next to Kaitlyn,” former Harbor Committee Chair Micala Delepierre previously said of Boxall’s work with now Chair Kaitlyn Mullen.

Boxall suggested the town check in with the projections each year, running the script she created to do so, and said she was available to teach them how to do so.

The changing levels have a lot of implications.

As the EPA says, “Sea level rise will make today’s king tides become the future’s everyday tides.”

According to the Schoodic Institute, “higher sea levels mean that storm waves and flooding are also higher. The worst case scenario of a storm arriving at the same time as a king tide occurred December 2022. A three-foot surge in water levels provided a glimpse of average sea level rises in the future.”

Previously, Catherine Schmitt, science communication specialist for the Schoodic Institute at Acadia National Park, has said that the sea level has risen eight inches in the past 74 years and that the rate of that rise is accelerating, doubling at 4.5 millimeters a year in the last 20 years as opposed to the 2.3 millimeter rate between 1950 to 2000.

Since 2020, The Landscape of Change (a partnership among the MDI Historical Society, Oceanarium, and Schoodic Institute) has been trying to illustrate sea level rise to people who live and work on the island using “history, science, and imagination to document and communicate the scope, speed, and scale of climate change on MDI.”

That work is being done throughout the island by town committees, town staff, researchers like Boxall, and organizations such as A Climate to Thrive.

Someone in the comments said it was poor journalism to not have converted centimeters to inches. Apologies. We kept the metric system because it tends to be a standard in science and is used more throughout the world.