Climate & Energy · Thursday, 18 June 2026
01 · Briefing · what happened
The ocean took the heat for us. Now it's giving it back
A new global climate report shows the ocean has soaked up more than 90% of the heat we've trapped — and the warmth it stored for decades is starting to surface as marine heatwaves, rising seas, and stranger weather.
Key takeaways
- A new global climate report finds the ocean has absorbed over 90% of the heat we've trapped, and Earth is now storing that heat twice as fast as in the late 20th century.
- The stored warmth is surfacing as record marine heatwaves, faster sea-level rise, and wilder swings between flood and drought on land.
- Clean energy is slowing how fast we add heat — California gas generation is down 60% from 2024 — but slowing the inflow doesn't lower a level that's already this high.
The most-shared climate story this week wasn’t a storm or a policy fight. It was a quiet sentence from a scientist who spends her career tracking where the planet’s extra heat goes. The answer, she wrote, is the sea — and the sea is now running a fever
What the new report says
A fresh global stocktake, the Indicators of Global Climate Change report, was published this week — the work of more than 70 researchers across 50-plus institutions, meant to fill the gap between the UN’s big assessments
That is simply the gap between the energy arriving from the sun and the energy the planet radiates back to space. In a stable climate the two roughly match. Greenhouse gases — the insulating blanket we keep thickening — trap heat that would otherwise escape, so more energy comes in than goes out. The report finds that imbalance has more than doubled since the late 20th century
Almost all of that stored heat — more than 90% — has gone into the ocean
The warmth is surfacing
The clearest sign the buffer is straining is in marine heatwaves — long stretches when a patch of sea turns abnormally, dangerously warm. In 2025 the number of marine-heatwave days was more than triple what it was in the early 1990s
That is not an abstraction. A severe marine heatwave bleaches coral, strips the kelp forests that shelter young fish, and empties fishing grounds. It also scrambles the ocean’s chemistry — its acidity, its oxygen, the carbon it trades with the air
The stored heat shows up on land too. A study published Wednesday in Earth’s Future modelled 698 UK river catchments and found that warming sharply raises “hydroclimatic whiplash” — rivers swinging fast between heavy downpour and long drought
The other half: the inflow is starting to bend
Here is the part that doesn’t fit the doom headline. The rate at which we pour heat into the system — the inflow — is, in places, beginning to slow.
In California, gas-fired power generation ran about 60% lower through 2026 than in 2024, as solar and imports filled the gap, according to grid figures reported this week
None of that cools the ocean. It slows how fast we keep adding to it. That gap — between bending the inflow and lowering the level — is the whole story.
What ordinary people are doing with it
US political and media attention to climate has thinned; coverage on major broadcast networks fell sharply in 2025, and several outlets cut climate reporters
The report’s author ends on the tool we’re now losing sight of, not gaining: four of five ocean-monitoring sites across the Pacific and Atlantic are set to close, with equipment already being pulled from the water
02 · Lesson · why it matters
The tap can slow and the bath still fills
Some harms come from a level, not a rate — and cutting the inflow leaves the level you already poured exactly where it is.
Two different questions
There are two ways to ask whether a thing is getting better, and they don’t give the same answer.
One is about the rate: how fast is it happening right now? The other is about the level: how much has piled up? Most of the time we ask the first and feel the second, and we don’t notice we’ve mixed them.
A bathtub makes it plain. The tap is the flow — water arriving per minute. The water in the tub is the stock — the level that’s accumulated. Turn the tap down and the flow drops. But the tub doesn’t drain. It just fills more slowly. If the drain is small, the water keeps rising even as you turn the tap toward off.
The ocean is a tub
The new climate report describes exactly this shape. The ocean has absorbed more than 90% of the extra heat we’ve trapped. That heat is the water in the tub. Our emissions are the tap.
For decades the tub had room, so the land barely felt the rise. Now the level is high enough to show — marine heatwaves running at more than triple their early-1990s rate, seas that have risen 23 centimetres since 1901 and are rising faster each decade.
Here’s the trap. You can do everything right on the tap and still watch the level climb. The ocean’s drain — the rate it sheds heat back to space — is slow. So even a real cut in emissions slows the filling without lowering what’s already in. The harm we feel is a function of the level, not the rate. And the level is the part we can’t undo by being better.
Why “doing better” doesn’t feel like winning
This is why climate progress can be real and disappointing at the same time, and why the two halves of this week’s news sit side by side without contradicting.
On the tap side, things genuinely moved. California burned 60% less gas this year than in 2024. A new line carries clean hydropower into New York. Ford started building cheaper batteries for an affordable electric truck. Each one slows the inflow.
On the level side, the ocean kept warming, the seas kept rising, the rivers kept swinging harder between flood and drought. Both are true. One is about the tap; the other is about the tub. Confuse them and you’ll either despair at good news or feel safe while the water climbs.
The shape is everywhere
Once you see it, the bathtub turns up far from the ocean.
Public debt is a tub — a balanced budget stops it growing but doesn’t pay it down. A repaired reputation is a tub — you can stop the bad behaviour today and still carry years of stored distrust. A skill, a friendship, a body’s wear and tear: built up by accumulation, not undone by a single good week. In each, the rate is the thing you control and the level is the thing you live with, and they move on different clocks.
The mistake is always the same one: judging a stock by its flow. “We cut emissions” answers a question about the tap. “Is the ocean cooler” is a question about the tub. They are not the same question, and only one of them is the one doing the harm.
What this asks of the reader
Seeing the difference doesn’t make the level drop. It changes what you expect from your own effort.
If a problem is a stock, then slowing it is worth doing and won’t feel like victory — because the thing already poured is still there, doing its work, on its own slow schedule. Patience isn’t optimism here; it’s just reading the gauge correctly. The reward for turning down the tap is a tub that fills slower, not a tub that empties.
And it places you inside the picture rather than above it. The heat in that ocean was poured over a lifetime, by everyone, for ordinary reasons — light, heat, travel, food. No single hand fills a tub this size, and no single hand drains it. The humility is in noticing that the level you’re judging is one you helped pour, on a clock far longer than your attention, into a system that holds the heat long after the tap is turned.
03 · Lab · your turn
The Bathtub
Move the tap and watch the level: rehearse why slowing the inflow of a stock never lowers what's already poured.
04 · Hope · carry this
The same report that measures how full the tub has grown also proves we now read the gauge better than ever — and the hands turning the tap down, from a California grid to a New York power line, are already moving. The level falls slowly, but it only ever falls because someone chose to stop pouring.
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