Why Rising Seas Could Lower a Hurricane’s Peak Surge—But Drown a Wider Area

This blog post and the “Deep Dive” podcast, created by NotebookLM, are based on “Combined impacts of hurricane strengthening and global mean sea level rise on future Atlantic storm surge events” by Danso et al. (2025).

It’s a scenario that seems frighteningly straightforward: as climate change causes sea levels to rise and hurricanes to strengthen, the resulting storm surges will inevitably get higher and more destructive along our coasts. This common assumption paints a simple picture of a rising tide of risk.

However, a new scientific study reveals a far more complex and often counter-intuitive reality. The future of coastal flooding isn’t just about higher water; it’s about how that water behaves and where it goes. This article breaks down the five most surprising and critical takeaways from this new research, which redefines how we should think about the threat of future storms.

These insights are based on a detailed modeling study by Danso et al., published in the journal Climatic Change in 2025, which analyzed 20 historical hurricanes under various future climate scenarios.

1. The Strange Paradox: Sea Level Rise Can Actually Lower Peak Storm Surge

The single most surprising finding from the study is that sea level rise doesn’t always lead to a higher peak storm surge. In many of the researchers’ simulations, adding sea level rise (SLR) alone actually caused the maximum height of the storm surge to decrease near the present-day shoreline, in some cases by as much as 0.7 meters (about 2.3 feet).

But this isn’t good news. The water doesn’t simply disappear. Instead, this finding points to a fundamental shift in flood dynamics: the surge water is being redistributed from the immediate coast to areas much farther inland.

2. It’s Not the Height, It’s the Reach: Water Is Pushing Farther Inland

The study highlights a critical distinction between the maximum height of a surge in one spot and the average height of the surge spread across the entire flooded area. While the maximum surge sometimes decreased at the coastline, the simulations consistently showed that both the average surge height and the total inundated area increased significantly with sea level rise.

This means that future storms, amplified by higher seas, will push a larger volume of water across a much wider landscape. The study synthesizes this core finding into a concise and powerful statement:

While decreasing maximum surge height may indicate reduced local extreme depths, increasing mean surge suggests widespread inundation.

The scale of this effect is staggering. The research found that combining a plausible 10% increase in hurricane intensity with 0.74 meters (about 2.4 feet) of sea level rise can expand the total area flooded by a storm by up to 400%.

3. Stronger Storms Are the Great Amplifier

To explore a plausible “worst-case” future, the scientists simulated what would happen if the historical storms were 10% more intense—a figure scientists use to model a plausible worst-case future based on upper-end climate projections. The results show that even a modest increase in storm strength has an outsized impact on storm surge.

When applied to present-day sea levels, a 10% increase in hurricane intensity raised both the maximum and mean surge heights for all 20 hurricanes studied. This change alone, without any sea level rise, was powerful enough to elevate the maximum surge by over 1 meter (3.3 feet) and expand the total flooded area by up to 26%. When combined with SLR, its effects become even more dramatic.

4. Not All Coasts Are Created Equal

The study makes it clear that the future of storm surge is not a one-size-fits-all problem. Local geography, particularly the slope of the underwater continental shelf, dramatically alters how a storm’s impact is magnified by climate change. The researchers identified two distinct patterns for storms hitting different types of coastlines:

• Gently sloped wide shelves (e.g., the Gulf Coast): In these areas, which have a wide, shallow offshore profile, a storm’s intensity is the key factor, with a greater absolute increase in wind speed leading to a proportionally higher surge.
• Steeply sloped narrow shelves (e.g., the South Florida Coast): Where the seafloor drops off more quickly, a different factor becomes dominant. In these regions, a hurricane’s forward speed becomes a more dominant factor in producing a greater surge increase when combined with sea level rise.

This finding complicates predictions and underscores the urgent need for highly localized, region-specific risk assessments rather than broad, generalized warnings.

5. The Bottom Line: More People in Harm’s Way

Ultimately, the science translates into a stark human reality. Because the total area of inundation is projected to increase in nearly all future scenarios, the number of people at risk from storm surge flooding is set to rise dramatically.

The study’s population analysis produced a stunning statistic: in some scenarios, particularly for storms hitting the low-lying Gulf Coast, the population exposed to storm surge could be more than 25 times greater than the number affected by the original historical hurricane.

Worryingly, this calculation is based on current population data. It does not account for future population growth in coastal areas, meaning the true number of people in harm’s way could be even higher.

A More Complicated Future

The combined threat of sea level rise and stronger hurricanes is more complex and dynamic than the simple model of “everything just gets bigger.” This research shows that while peak surge at the coast might not always increase, the far greater danger lies in the expansion of flooding—wider, more extensive, and pushing deeper into communities once thought to be safe.

The science reveals a more complicated and location-dependent picture of future storm risk. As we look ahead, the critical question becomes: how can coastal communities adapt their strategies to protect areas that were once considered beyond the reach of the sea?

The infographic was generated by Notebook LM.

Danso, D., Patricola-DiRosario, C. & Balaguru, K. Combined impacts of hurricane strengthening and global mean sea level rise on future Atlantic storm surge events. Climatic Change 178, 238 (2025). https://doi.org/10.1007/s10584-025-04081-5