Ocean Heat Absorbed Today

Estimated heat entering the ocean since midnight UTC, in exajoules. One exajoule is about 15 hours of the whole world's primary energy supply.

Ocean heat content is assessed from float and float-derived data over months, not continuously. The per-second figure conveys the scale of that assessment, not a moment-by-moment count. The measured reading paired with it is NOAA's heat content of the upper ocean, published once a year: the stock this counter adds to, not the flow itself. Its change from one year to the next is the heat this counter accumulates over a year, less the part that reaches the deep ocean below the layer the reading covers, which it leaves out — and because the counter runs at a long-term average rate, it will not match any single year's change.

Nobody counts this as it happens. EarthNow takes a published figure for the whole day, divides it by the 86,400 seconds in a day, and multiplies by the seconds elapsed since midnight UTC. So the value climbs smoothly and is the right order of magnitude — but the smoothness is arithmetic, not observation. Nothing happening in the world is being watched in real time.

value = daily total ÷ 86,400 × seconds since 00:00 UTC

A consequence worth knowing: the counter resets at midnight UTC, not at your midnight. And because the figure advances at a constant rate, this page cannot tell you whether today is unusual. For that you need a measurement.

Ocean heat content rises by about 11.3 zettajoules (~11,300 EJ) a year — NOAA's 1993–2024 trend, not any single year's reading.

Daily total

30 EJ

Published by

NOAA NCEI (2026)

The figure is theirs; the running total is ours. Cite them for the number, and EarthNow for what it looks like as it accumulates.

NOAA publishes a real measurement related to this signal: Ocean heat content (0–2,000 m). It is an instrument reading with a date attached, not an estimate. It measures a related quantity, not this counter's own: cite it for what it measures, and never as a measured value of the figure above.

This counter

Heat entering the ocean since midnight UTC, at every depth, at a long-term average rate

In EJ · a flow, what is added

The reading

Heat held in the upper ocean, measured against a long-term average, as a yearly mean

In ZJ · a stock, one part of what this flow adds to

The reading is the stock this flow fills, down to the depth in its name. Heat that goes deeper is in this counter and not in the reading.

Heat held in the top 2,000 metres of the ocean, from Argo floats and ship profiles, as a yearly mean measured against a long-term average. The ocean absorbs most of the heat greenhouse gases trap, so this is where warming accumulates. One zettajoule (ZJ) is 10²¹ joules.

• The imbalance between sunlight arriving and heat escaping, which greenhouse gases control
• How deep the heat mixes, which decides whether it returns in a decade or a century
• Ocean circulation, which moves heat away from where it entered