Sea Level Rise Project

Sea level rise on Islesboro became more evident with the conclusion of 2022. As predicted by the Maine Geological Survey simulation software, flooding occurred at the base of the lighthouse, along Ferry Road and at the Narrows. The road at the Narrows was closed to traffic for 2 hours.

The images above show how sea level rise threatens the light station. The images on the left and right were taken on December 23, 2022. The center image shows the predicted water height with future H.A.T. (high astronomical tides) at three different heights. The blue line shows H.A.T. with a one foot rise in sea level, the yellow line shows H.A.T. with a three foot rise in sea level, and the red line shows H.A.T. with an eight foot rise in sea level.

Observations are the beginning of the story of our awareness of sea level rise. The next chapter is figuring out how to protect our community from sea level rise or how to mitigate at-risk sea level rise sites. The Grindle Point Light Station committee members have made many observations of sea level rise at the light station and have obtained definite surveyor waypoints, including determination of high astronomical tide level, which are essential to understanding this threat. The committee now needs expert help to determine mitigation steps.

The Natural Resources Defense Council has proposed the following mitigation ideas: do nothing, protect, accommodate, advance, retreat, and retreat plus ecosystem-based mitigation. This article IPCC: Sea Level Rise Adaptation Is Essential, Not Optional is worth reading. It is short and scary, as scary as looking at our light station at astronomical high tides with storm surges. One of the conclusions of the report is to act decisively and to act now.

Which of the six adaptation strategies is best for Islesboro? For the past 170 plus years, we have embraced the “do nothing approach”. The “advance”, “retreat”, and “retreat plus ecosystem-based” adaptations are limited by the land area at Grindle Point, which will become Grindle Island as the sea level rises nine feet by 2100.

This leaves us with the “protect” or “accommodate” options. The “protect” option has been a stop-gap measure employed along the coast with ever-increasing sea level rise; a seawall will have only temporary success, with vertical extensions to the wall needed as the waters rise. The “accommodate” option means raising the lighthouse. Going up eliminates having to move the lighthouse to an unknown location if one even exists, and maintains the light station’s welcoming iconic image. The financial cost to raise the lighthouse will be expensive and must be agreed upon as worthwhile by the community. Do we act decisively now or wait for more flooding events in the future?