Giving the Water Somewhere to Go

What does 5-15 feet of sea level rise actually mean?

Here's a number that should keep every coastal city planner up at night: National Geographic projects that sea levels could rise 5 to 15 feet by the end of this century.

That's not a typo. And it's not a worst-case-only projection.

To put it in context: a 5-foot rise would permanently flood parts of Miami, New York, Shanghai, Mumbai, and Jakarta. A 15-foot rise would redraw the map of the world. More than a billion people currently live within 65 feet of mean sea level. We're not talking about distant generations here — we're talking about infrastructure, communities, and entire economies that exist right now.

And here's what makes this particularly urgent: the rate is accelerating. Sea levels rose about 6 inches total in the entire 20th century. From 2000 to 2024 alone, they rose over 3 inches. The curve is steepening.

The standard responses — seawalls, managed retreat, incremental mitigation — were designed for a slower timeline. They weren't built for what's actually coming.

That's why I believe we need to fundamentally reframe the question. Instead of asking "How do we hold the ocean back?" we should be asking "Where can we give it somewhere to go?"