Opinion: Cape Cod's growing population a balancing act between growth, nitrogen pollution

Cape Cod's captivating beauty and delicate ecosystems demand careful management as its demographics evolve. The recent surge in year-round residents and extended stays by seasonal homeowners necessitates thoughtful infrastructure investments, particularly in nitrogen mitigation measures, to ensure its enduring charm. While increased residency offers economic opportunities, it raises concerns about the environmental impact of intensified human activity.

Despite earlier predictions of decline, Cape Cod's population has grown by a remarkable 9% or 20,000 since 2019, surpassing 232,000 residents in 2022. This surge directly contradicts the persistent negativity surrounding an exodus from the Cape, as anticipated by a 2017 Cape Cod Commission report. Fueled by remote work, conversions from seasonal to year-round residency, and the allure of its environment, this growth presents both opportunities and challenges, including strained infrastructure and environmental concerns. Notably, this upward trend has sustained even years after the pandemic's peak, showcasing the enduring appeal of Cape Cod.

As the population grows, a notable shift toward year-round occupancy is underway. Between 2016 and 2022, the number of occupied units increased by 5,600, primarily due to the conversion of nearly 2,500 seasonal homes and the overall housing stock expansion. This has led to an all-time high of nearly 100,000 occupied units, with the number of seasonal homes now closer to 2012 levels.

Further contributing to this trend, seasonal residents are extending their stays, blurring the lines between seasonal and year-round residency. New U.S. Census data reveals a substantial shift in duration, with 18,700 units occupied for at least 10 months in 2021, increasing to over 20,000 by 2022. One out of every three seasonal units is now occupied for at least 10 months, highlighting the significant implications for Cape Cod's economy and environment.

For effective infrastructure and public services planning, it is crucial to consider individuals residing on Cape Cod for at least 10 months annually as part of the year-round population. This necessitates incorporating an additional 37,400 residents into the Cape's population of 232,400 as of 2022, assuming a conservative estimate of two occupants per household based on a recent second homeowner survey.

Further underscoring this trend, a 2021 survey revealed that approximately 20% of second homeowners plan to transition to year-round residency within the next five years. This translates to 11,000 seasonal homes becoming permanent residences, potentially adding another 22,000 residents to the Cape's population. This indicates a clear trajectory toward becoming a more year-round community.

While seasonal homes traditionally boosted the tax base and summer economy, extended stays by seasonal residents are now bolstering year-round economic sectors. This is evident in the Trade, Transportation and Utilities sector, which saw a 1,060-worker increase during the winter of 2023 compared to 2016. Additionally, over 90% of second homeowners make local purchases such as groceries, garden supplies and hardware, further contributing to year-round economic activity.

However, the surge in population strains existing infrastructure, demanding upgrades and expansions to critical services such as roads, bridges, emergency services, water and wastewater treatment facilities. While critical infrastructure upgrades are necessary to accommodate Cape Cod's growing population and thriving economy, mitigating the potential environmental impact, particularly nitrogen pollution, remains paramount. Excess nitrogen, often originating from fertilizers and septic systems, disrupts delicate ecosystems by promoting harmful algae growth and depleting oxygen levels in Cape Cod's waters.

Year-round occupancy concentrates nitrogen pollution in Upper and Mid-Cape towns, particularly Falmouth, Dennis and Bourne, which experienced the highest conversion rates of seasonal homes. Orleans, Provincetown and Brewster, meanwhile, saw the most additions of seasonal units. This shift necessitates infrastructure upgrades to address increased nitrogen loading in these areas, protecting property values and the Cape's overall economy.

In addition, a recent Massachusetts Department of Environmental Protection presentation reveals that water usage across the Cape, including the Upper, Lower and Mid-Cape regions, has surpassed the 2015-2019 average as of 2020. Notably, Sandwich, Yarmouth, Dennis and Harwich experienced a significant increase exceeding the long-term trend by 11% to 20%, while other towns such as Bourne, Falmouth, Barnstable, Brewster, Orleans and Chatham saw a more moderate rise of 1% to 10%. This trend could worsen, as Barnstable, Falmouth, Mashpee, Sandwich, Dennis and Yarmouth, which collectively contributed 70% of the Cape's population growth between 2020 and 2022, also contain many nitrogen-impaired areas. This suggests a potential increase in wastewater outflow and nitrogen levels due to growing year-round residency.

Cape Cod's intensifying human activity necessitates swift action to protect its fragile ecosystem. Accelerating nitrogen mitigation is crucial for preserving the Cape's beauty and economic well-being. Striking a balance between growth and protection is essential. All residents must redouble their efforts to safeguard this special place through nitrogen mitigation, sustainable practices and environmental stewardship. The time for action is now.

Mahesh Ramachandran Ph.D. is chief economist at Smart Growth Economics LLC, former environmental economist at the Cape Cod Commission and former chief economist at the Massachusetts Executive Office of Labor and Workforce Development.

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This article originally appeared on Cape Cod Times: Opinion: Cape Cod's growing population brings environmental challenges