Virtually every fish in one of Arizona’s largest lakes has died after the reservoir fell to less than 1% of its capacity. This spring, the mountain snow that feeds the reservoir reached just 2% of its normal level. With almost no inflow, the lake shrank dramatically, the water overheated, oxygen levels collapsed, and nearly 100% of the fish suffocated. But drought wasn’t the only reason. Even as the reservoir was collapsing, water continued flowing downstream to supply farms under agreements written decades ago, when a snowpack collapse this severe was considered unthinkable. The ecosystem kept losing water while the climate that sustained it had already changed. The rules were built for a world that no longer exists. Climate change isn’t only testing ecosystems. It’s testing the systems we built to manage them. Before and after: San Carlos Reservoir, Arizona (2023 vs. 2026). [Source: NASA Earth Observatory, June 2026.]