Climate change is often talked about in terms of heat, but one of its most immediate impacts is water in the atmosphere.
As the atmosphere warms, it can hold more moisture. In fact, for every degree Celsius increase in temperature, the air can hold about 7% more water vapor. That extra moisture has to go somewhere. When conditions are right, it falls as rain, often quickly, intensely, and in concentrated bursts. Add to that warmer oceans (which fuel storms) and shifting weather patterns that can cause storms to stall over one area, and you get a new reality: heavier, more unpredictable rainfall.
The challenge is that our cities were not built for this version of the climate.
Most urban drainage systems (storm sewers, culverts, retention basins, etc.) were sized using historical rainfall data. Engineers planned for what used to be considered “extreme” events, like a once-in-100-year storm.
But those assumptions are breaking down. What was once rare is becoming more frequent. The infrastructure’s peak flow capacity that worked well for decades is now being pushed beyond its limits.
At the same time, cities have become more paved and denser. Water has fewer places to go for short duration storage. When it rains heavily, it runs off quickly, with higher flows that overwhelm systems that were never designed for that volume or intensity. The result is distressingly familiar: flooded streets, backed-up sewers, and water entering homes—sometimes on one block but not the next.
So what can cities do?
The instinctive answer might be to upgrade everything and to rebuild entire drainage systems. But that’s rarely feasible. The costs often run into billions; the disruption is massive, and the timeline stretches over decades. Instead, cities are facing a different kind of challenge: how to be precise.
Flood risk is not evenly distributed. Often, a single bottleneck at a small culvert or an undersized pipe can affect hundreds of properties. Fixing that one constraint can dramatically reduce risk across an entire neighborhood. The goal is no longer to build bigger systems everywhere, but to make targeted, high-impact investments where they matter most.
But infrastructure is only part of the equation.
A significant portion of flood risk exists at the property level. Basement vulnerabilities, poor grading, and lack of backflow protection are all common factors that often determine whether a building floods or not, often before runoff gets to the street. Even a well-functioning city system can’t fully protect a property that isn’t prepared. That means adaptation must happen not just at the city level on public property, but at the level of individual homes and buildings.
This is where a more integrated approach becomes essential.
NOAH’s CityTwin™ helps cities see the full picture. It models how water moves through infrastructure during extreme storms, identifies system constraints, and shows where investments will reduce the most risk. It gives municipalities the ability to allocate capital more effectively—moving from broad spending to targeted action, maximizing resilience.
NOAH’s ClimateGuard™ brings that same level of clarity to the property level. It provides building-specific risk insights, recommends practical mitigation steps, and tracks improvements over time. It helps property owners understand their risk and, importantly, what they can do about it.
Together, they create a coordinated adaptation platform. CityTwin™ helps cities decide where to act. ClimateGuard™ helps residents and property owners take action. One addresses infrastructure. The other addresses individual properties.
In a world of increasing rainfall and rising risk, resilience is no longer just about infrastructure. It’s about alignment between cities, citizens, and the data that connects them.
That’s how climate adaptation in cities becomes not just possible, but scalable.