Why Our Coastlines Are Changing and How We Can Prepare
The ocean is rising at an accelerating rate, transforming the landscape of our coasts faster than many anticipated. While sea level rise can feel like a distant, abstract problem, the reality is that it is already reshaping communities today. Understanding the why and how of this process is the first step toward building more resilient, safer neighborhoods.
Why Is the Ocean Rising?
Sea level rise is driven by two primary factors:
1. Thermal Expansion: As the ocean absorbs heat from our warming atmosphere, water expands. Think of it like a pot of water on a stove: as it gets hotter, it takes up more space.
2. Melting Ice: The biggest factor, however, is the collapse of polar ice sheets. For millennia, snowfall on Greenland and Antarctica roughly balanced out the ice melting into the sea. That balance is broken. Our reliance on fossil fuels—which release heat-trapping greenhouse gases—has caused global temperatures to rise, accelerating the melt of these massive ice reservoirs.
The Hidden Risks: Groundwater and "Surprises"
When experts discuss sea level rise, the focus is often on high tides hitting the streets. But there is a hidden threat: groundwater.
In coastal regions, the water table underground often rises in tandem with the sea. This means that even if a community builds sea walls to block incoming waves, the water
may simply rise from beneath, flooding roads and basements, and potentially mobilizing buried pollutants from old industrial sites or septic tanks. Research, such as recent
findings in the San Francisco Bay Area, shows that considering groundwater can double the estimated flood impact.
Furthermore, scientists are discovering that ice sheets are more volatile than older models suggested. Recent studies regarding the 'grounding lines' of glaciers in Greenland indicate that warm water is reaching further inland than we thought, potentially increasing future sea level projections significantly.
What Does This Mean for Our Communities?
We are moving out of a period of stability. As author Susan Crawford noted regarding cities like Charleston, we must plan for significant changes in our lifetime, not just in the
distant future.
The path forward requires proactive, science-based planning:
● Conduct Vulnerability Studies: Every coastal community should conduct a thorough assessment that accounts for both coastal flooding and rising
groundwater levels.
● Smart Development: We must stop building new structures in areas that will soon be in the path of rising waters.
● Proactive Cleanup: We need to prioritize cleaning up brownfields, old gas stations, and hazardous waste sites before they are inundated by the rising sea.
● Plan for Transition: In some areas, this may mean managed relocation or restoring wetlands that can act as natural buffers against the sea.
How You Can Take Action
The climate crisis is daunting, but we have the power to mitigate these risks through policy, advocacy, and local action. If we work together to push for aggressive climate restoration and smarter local planning, we can protect our homes and natural ecosystems.
Get Involved:
● Urge Local Leadership: Contact your city council or planning board. Ask: "Has our city completed a vulnerability study that includes both coastal flooding and
groundwater rise?"
● Join the Conversation: Connect with your local Sierra Club chapter to see how other units are addressing coastal resilience.
● Support Climate Restoration: Advocate for policies that draw down carbon from the atmosphere—the only way to truly stabilize our climate in the long term.
Get in touch with the Sierra Club Climate Adaptation & Restoration Team (CART) to learn more: By joining the Climate Leaders Circle Campfire group.