by Daniel Brouse
July 19, 2025
One of the most fundamental principles in science is observation. For the past couple of decades, I have observed the evaporation rate from my swimming pool steadily increasing. While it may seem like a small backyard inconvenience, it’s a clear, everyday confirmation of our warming climate.
As global temperatures rise, the atmosphere’s capacity to hold moisture increases. According to the Clausius-Clapeyron relation, for every 1°C (1.8°F) increase in temperature, the air can hold about 7% more water vapor. Many summer days now run 10° above historical averages, meaning the air can hold around 70% more water than it once did. That’s why my pool is losing water faster and faster each year.
This isn’t just about pools; it’s about our drinking water, food systems, and safety. Higher evaporation rates are depleting reservoirs and other freshwater sources, shifting water into the atmosphere, and often returning it in damaging ways. With a warmer, wetter atmosphere, we are seeing a marked increase in the intensity and frequency of extreme rainfall events. The United States has already seen record numbers of so-called “1,000-year” and “500-year” floods this year, with nearly every state experiencing damaging flash floods.
This increase in flash flooding is part of a vicious cycle: water evaporates from critical freshwater sources, the air holds more moisture, and storms unleash torrents of rain that infrastructure cannot handle, causing catastrophic flooding while failing to replenish water sources in sustainable, usable ways.
So, to all the folks in New Jersey cleaning up after yet another round of flash floods: if you happen to come across my pool water, I’d appreciate it if you could send it back.
In the meantime, we must recognize that these local observations are snapshots of a much larger global system in crisis—one that demands rapid, systemic change if we hope to stabilize water resources, protect communities, and adapt to the climate realities already unfolding around us.
* Our climate model — incorporating complex social-ecological feedback loops within a dynamic, non-linear system — projects that global temperatures could rise by up to 9°C (16.2°F) within this century. This far exceeds earlier estimates, which predicted a 4°C rise over the next thousand years, and signals a dramatic acceleration of warming.
Tipping points and feedback loops drive the acceleration of climate change. When one tipping point is breached and triggers others, the cascading collapse is known as the Domino Effect.
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