By Nicole Tarnowsky, Laura Briscoe
Sep 19 2019
One of the most visually apparent impacts of climate change are the emerging ghosts forests of eastern North America. As sea levels rise, coastal forests are increasingly flooded with sea water, turning what was once land with fresh water into intertidal regions that are now inundated with salt water. This turns the forests into marshland, leaving just the skeletons of dead trees submerged in water. The visuals of this transition inspired artist Claire Harbage to create this photography project.
On average globally, sea levels are expected to rise between 1.3 to 3.9 feet by 2100. In the Mid-Atlantic region from Massachusetts to North Carolina the sea levels are rising three times as fast as the global average¹. In addition to ice caps melting, this is because the land in this region is sinking from the slow geologic effects of the last Ice Age, and also a slowing of the Gulf Stream resulting in less water moving away from the coast².
The trees that live on this former high ground are poisoned by salt water. One of the most susceptible trees to salt water is Atlantic White Cedar¹, it is the first tree to die off in this new environment. Others that follow include Red Maple and Sweetgum¹. As the habitat changes, salt tolerant species move in that can survive in marshland, such as the invasive grass Phragmites¹.
This region is also considered a biodiversity hotspot for lichens³. Garden scientists have done intensive field work over the past several years that has yielded many important scientific discoveries, including species new to science. It’s hard to quantify the potential losses to biodiversity in the Mid-Atlantic when we are not even sure how many species may be there.
Although this sounds dire, an optimistic way to look at this transition is that the environment is changing, but not necessarily for the worse. These new intertidal regions can be seen as useful ecosystems that filter pollutants, prevent erosion, and store more carbon than forests do². Ironically, marshlands are also better at tempering the flooding caused by rising sea levels². With the right land management there is the potential to adapt to this new environment as best we can.
Sources:
¹ Kirwan, M. L. & Gedan, K. B. (2019). Sea-level Driven Land Conversion and the Formation of Ghost Forests. Nature Climate Change 9: 450-457. Retrieved 12 September 2019, from https://www.nature.com/articles/s41558-019-0488-7.epdf
² Chrobak, U. (2019). Ghost forests are sprouting up along the Atlantic Coast. Popular Science. Retrieved 12 September 2019, from https://www.popsci.com/ghost-forests-sea-level-rise/
³ Lendemer, J. C & Allen, J. L. (2014). Lichen Biodiversity under Threat from Sea-Level Rise in the Atlantic Coastal Plain. Bioscience. 64(10): 923-931. Retrieved 18 September 2019, from ttps://doi.org/10.1093/biosci/biu136
NOAA (2018). What is a ghost forest? National Ocean Service website. Retrieved 12 September 2019, from https://oceanservice.noaa.gov/facts/ghost-forest.html
