Global warming, a significant consequence of climate change, intensifies the hydrological cycle, leading to increased evaporation and atmospheric moisture. This, in turn, results in more intense rainfall events. Coupled with human modifications of natural landscapes, these factors contribute to more frequent and devastating floods in developed areas.
For every 1°F increase in temperature, the atmosphere can hold approximately 4% more water vapor. With average global surface temperatures over 2°F warmer in 2020 compared to a century prior, the atmosphere now holds nearly 9% more moisture. This heightened moisture content significantly increases the potential for heavier rainfall and more severe storms.
Recent scientific findings indicate a future trend towards hotter, wetter conditions globally. Preceding heatwaves exacerbate the situation by drying out soils, diminishing their capacity to absorb rainwater during subsequent heavy rainfall, thereby escalating flood risks.
Human development patterns have drastically altered natural landscapes, both inland and along coastlines and rivers. These alterations impede natural water absorption, causing rainwater to accumulate on the surface and transforming beneficial rain into destructive floods.
The proliferation of roads, sidewalks, buildings, shipping canals, dams, and modern agricultural practices has eliminated crucial natural landscape features that once slowed down rainwater runoff and facilitated deep underground absorption. Furthermore, existing stormwater management systems are often outdated and lack the capacity to manage the increased volume and intensity of contemporary rainfall events.
Compounding the problem, continued residential development in known flood-prone areas exacerbates risks. Disseminating accurate and current flood-risk information is crucial to guide individuals away from vulnerable zones. Enhanced government planning and financial resources for community recovery are also essential when floods inevitably occur.
Infographic: Learn how natural infrastructure can mitigate flood risks (PDF)
