Analysis
Satellite and tide‑gauge records show global mean sea level rising at ~3.3 mm/yr over the past three decades, which equals roughly 33 cm (about one foot) per century. However, the rate is accelerating, and climate models project rises of 0.3–0.8 m by 2100 under high‑emissions scenarios, far exceeding a simple one‑foot‑per‑century extrapolation. Lomborg’s statement presents the current rate without acknowledging this acceleration, thereby understating the potential scale of future impacts.
Background
Sea‑level rise is driven by thermal expansion of warming oceans and melting of glaciers and ice sheets. Observations confirm a steady increase, but the IPCC reports a clear acceleration over recent decades. Policymakers and scientists warn that future rises could threaten coastal infrastructure, necessitating both mitigation and adaptation measures.
Verdict summary
The claim that sea level is rising about one foot per century is roughly correct for recent observations, but it omits the accelerating trend and future projections that could make the problem far larger than implied.