Warming of the World Ocean

TLDR

The study quantifies interannual‑to‑decadal variability of the world ocean’s heat content from the surface to 3000 m during 1948–1998. Between the mid‑1950s and mid‑1990s, the world ocean’s heat content rose by ~2 × 10²³ J, yielding a volume‑mean warming of 0.06 °C (0.3 W m⁻²), with pronounced increases in the 300–1000 m and deeper North Atlantic layers and a 0.31 °C rise in the upper 0–300 m, while the Atlantic and Pacific warmed since the 1950s and the Indian Ocean since the mid‑1960s, though the warming was not monotonic.

Abstract

We quantify the interannual-to-decadal variability of the heat content (mean temperature) of the world ocean from the surface through 3000-meter depth for the period 1948 to 1998. The heat content of the world ocean increased by ∼2 × 10 23 joules between the mid-1950s and mid-1990s, representing a volume mean warming of 0.06°C. This corresponds to a warming rate of 0.3 watt per meter squared (per unit area of Earth's surface). Substantial changes in heat content occurred in the 300- to 1000-meter layers of each ocean and in depths greater than 1000 meters of the North Atlantic. The global volume mean temperature increase for the 0- to 300-meter layer was 0.31°C, corresponding to an increase in heat content for this layer of ∼10 23 joules between the mid-1950s and mid-1990s. The Atlantic and Pacific Oceans have undergone a net warming since the 1950s and the Indian Ocean has warmed since the mid-1960s, although the warming is not monotonic.