Eastern Shore Farmers Are Salty
By Miles Bolton
Sea level rise (SLR) is no longer a matter of varied projections made by the scientific community, SLR is a current reality that will continue to worsen in the coming years. Governments, farmers, and coastal developers are in the process of figuring out how to cope with SLR as the rising tides threaten farms, coastal property, and in some cases entire cities. Indonesia presents one of the more extreme examples showcasing the severe consequences associated with SLR. Right now, the Indonesian government is in the process of choosing a new capital, as Jakarta appears doomed to sink into the ocean due to the coupled impact of land subsidence and SLR.
As a graduate student at Horn Point Laboratory (University of Maryland) living on the Eastern Shore of Maryland, I’ve both heard about and seen the effects of SLR just miles from where I live. Driving out towards Blackwater Wildlife Refuge (Wetlands/Salt Marsh habitat) from Cambridge, MD (Dorchester County) it has become necessary to check the tide charts, as the roads around the refuge regularly flood at high tide or during heavy rainfall. I was aware of the potential impacts of SLR before I moved to the Eastern Shore but I didn’t know the full extent of it or how it impacted the communities of the Eastern Shore. That was until I sat in on a seminar at Horn Point where Kate Tully, an agroecologist at the University of Maryland (College Park), presented her research on the effects of salt water intrusion on agriculture in the Eastern Shore of Maryland. Kate Tully is also working with Keryn Gedan, a wetland ecologist at George Washington University, to put together a comprehensive map of salt levels in soils, wells, soil types, hydrogeologic layers, and ditches to help farmers monitor the potential for salt water intrusion on their fields.
For those unfamiliar the Eastern Shore is located within the Maryland portion of the Delmarva Peninsula, which is shared with Delaware and Virginia. The Eastern Shore of Maryland is on the eastern side of the Chesapeake Bay in relation to D.C and Baltimore.
In the United States, where SLR projections seem to be treated as a matter of opinion rather than an objective reality, many farms on the Eastern Shore of Maryland are experiencing salt water intrusion as a precursor to accelerated SLR. The Eastern Shore of Maryland is particularly vulnerable to SLR due to the low elevation of the Delmarva Peninsula. SLR is projected to rise 3.7 feet in Maryland by 2100 as compared to the global average of 2.7 feet. 400 islands within the Chesapeake Bay have vanished completely as a consequence of SLR in the past 400 years, with more areas on track to become submerged in the coming years. SLR poses a serious threat to farmers on the Eastern Shore as agriculture is a significant economic driver in the region.
“It’s happening now. We often talk about sea level rise and climate change as this thing that’s going to happen in the future. And it’s already happening. We’re at the point where we’re already losing farm fields”- Kate Tully
The Eastern Shore is a major poultry producer, with Somerset County (Southernmost County of Eastern Shore, MD) ranking as the country’s 6th largest poultry producer. The majority of cultivated land in the Eastern Shore is used to grow corn and soybeans to support the regions poultry industry. In 2017, the poultry industry likely peaked reaching over $1 billion in production for the first time ever. Salt water intrusion on the Eastern Shore looks like it could interrupt the supply chains of soybeans and corn that are needed to support the poultry industry. 50,000 out 207,000 acres in Somerset are currently being cultivated for soybeans and corn, however due to salt water intrusion farmland has been converted to salt marsh involuntarily at a rate of 100 acres per year since 2009. So far, approximately 4,000 acres of farmland, rendered useless by salt saturated soils, have been placed into agricultural retirement programs in recent decades. Farmers often don’t report salt intrusion on their property for fear of losing property value, which makes it increasingly difficult to monitor soil salt content and try to prepare their farms for SLR. The question at this point being, how much time do the rest of the farms in Somerset County have before their farms are too saturated with salt to grow anything? Corn can’t grow in soil that has a soil salt content above 0.8ppt (parts per thousand) and right now the soil salt content in Somerset County sits between 6-7ppt, on the cusp of agricultural oblivion.
“The whole region is a window into the future”- Keryn Gedan
How Does Saltwater Intrude?
Saltwater intrusion into aquifers
Aquifer withdrawals have induced land subsidence (Like Jakarta) and allowed for salt water to more easily enter the water table.
Upwards wicking through soil into shallow water table
Other Variable Consequences of Salt Water Intrusion
The looming prospect of widespread salt water intrusion in Somerset County introduces a complex suite of problems including the release of formerly sequestered nitrogen, phosphorous, and carbon dioxide compounding the problems associated with salt water intrusion and SLR. “We expect large nutrient losses as coastal farms undergo saltwater intrusion” Tully, “If you want to extract nitrogen or phosphorus from the soil, you add saltwater”. The nutrients lost from these farms would enter the Chesapeake Bay as saltwater seeps into agricultural fields. The escaped nutrients could negatively impact water quality in the surrounding area and increase the risk of harmful algal blooms due to increased nutrient enrichment in the water column. It’s difficult to estimate the total impact of the released nutrients on the Bay, but considering the heavy use of artificial fertilizers on corn fields on the Eastern Shore one can imagine that there would be a significant influx of nutrients into the Bay. I’m not going to make any projections of the potential influx of nutrients as a result of SLR on the Eastern Shore as salt water intrusion is still being mapped and there isn’t sufficient data as of yet.
Nonetheless, the bottom line is this. Eastern Shore farmers as well as any farmer whose livelihood is being threatened by the effects of climate change need help. Adapting to the challenges presented by climate change requires a concerted effort between farmers, scientists, and governmental agencies to develop sustainable agricultural solutions to mitigate climate change associated losses. The verdict is still out on how to best combat salt water intrusion on farms. Some experts encourage planting salt tolerant plants as buffers to help reduce overall soil salt content whereas others believe in the use of more salt tolerant crops and/or engineering salt tolerant GMO crops. The effectiveness of each of these options is up for debate however none of these options will stop the slow march of SLR and saltwater intrusion onto farmland.
Getting "Radical" and Practical
A more radical solution that I’ve pondered to help farmers cope with SLR on the Eastern Shore, is a potential subsidy driven program that’d either help farmers find suitable farmland elsewhere or transition to aquaculture if they don’t want to vacate their land. Aquaculture, particularly oyster and seaweed aquaculture, is on the rise in the U.S and is an industry that has been practiced successfully in Asia for centuries. Currently global aquaculture production is being dominated by Asia (89%), China alone accounting for 62% of production. The U.S ranks 16th globally in aquaculture production and aquaculture accounts for 21% of the U.S’s total seafood production. Due to drastic declines in wild caught fish, we currently are suffering from a seafood trade deficit. Nearly 90% of the seafood consumed in the U.S was imported (over 50% of these imports are from aquaculture), NOAA last reported a seafood trade deficit of $14.1 billion in 2017. $21.5 billion dollars worth of seafood were imported while only $5.4 billion dollars worth were exported.
The solution to balancing the deficit is aquaculture. The ocean is simply not as fruitful as it once was due to chronic overfishing so we must change our approach to seafood production. Aquaculture sales in the U.S rose 13% on average from 2007-2011, and marine aquaculture alone experienced a 3.3% increase in production on average from 2009-2014. The U.S has the potential to become a global leader in aquaculture and should look for ways to boost production on a larger scale. Aquaculture could be a remedy for adapting to climate change, reducing the trade deficit, and maintaining a competitive economy.
Tools to Monitor SLR in your region
If you’re curious about how SLR could impact your neck of the woods, there are some great resources provided by NOAA to help forecast SLR rise anywhere in the United States. Check out the link below to see for yourself.
SLR Viewer: https://coast.noaa.gov/slr/