Overview
- The two studies published June 10, 2026, use long-term tide gauges and model counterfactuals to attribute most recent increases in extreme coastal water levels to human-caused warming.
- One paper reports that events once labeled 1-in-100-year are now about 12 times more likely on average and that human influence alone has roughly quadrupled their frequency since 1900.
- The second study finds the signal of human-driven sea-level rise at about 97 percent of tide gauges and attributes roughly 58 percent of extreme-water days from 2000 to 2018 to climate change.
- Local factors such as land subsidence, tide range, and regional ocean behavior create wide variation so that places like Wellington now get 1-in-100 floods roughly twice a year and Sandy Hook shifted to about a 1-in-16‑year event.
- The rise in baseline sea level—about 20 centimeters since 1900 from thermal expansion and ice loss—means even small storms cause bigger floods and makes current flood-frequency estimates and coastal defenses out of date.