The climate's slow answer to a fast question

Climate & Energy 4 min 80 sources

A new study finds that reaching net-zero really does stop the warming, and then slowly reverses it, even as this year's electricity demand and oil keep the carbon flowing.

Key takeaways

A new Nature study finds that reaching net-zero does not just stop warming; over centuries the planet slowly cools by at least 0.6 degrees Celsius.
But emissions are still rising: global electricity demand is outgrowing even a fast clean-energy boom, so more carbon keeps entering the air.
A record "super" El Nino and deadly European heat show the warming already banked, even as the long-run picture turns hopeful.

Does stopping actually work?

The question under every climate headline is simple. If we cut emissions to nothing, does the planet stop heating, or are we already locked in? A new analysis in Nature Climate Change gives the clearest answer yet [9]. Reaching net-zero, where any greenhouse gas still emitted is matched by an equal amount removed, does more than halt the warming. Over the following centuries, temperatures slowly fall, by at least 0.6 degrees Celsius, the authors find [9].

For years this was genuinely uncertain. Some climate models showed extra warming after emissions stop; others showed cooling [9]. The study pins the answer down using three well-measured properties of the carbon cycle, and settles on a small, downward drift [9]. It is one modelling result, not the last word. But it lands on the reassuring side: we are not condemned to keep heating once we stop adding carbon.

That “once we stop” is the whole catch. And on that front, the news this week is mixed.

The tap is still open

Global electricity demand is growing faster this year than last, up 3.6%, with a forecast 3.8% next year, the International Energy Agency says. The IEA is the West’s energy watchdog [6]. Total power use rises from 28,600 terawatt-hours in 2025 toward 30,700 by 2027 [4]. Industry, air conditioning, electric cars and data centres are all pulling harder [6].

Clean power is racing to keep up. Renewables are set to overtake coal as the world’s largest source of electricity this year, the IEA says [4]. Solar alone adds around 600 terawatt-hours in 2026, and passes wind to become the second-biggest renewable source after hydropower [4]. Renewables’ share of the mix climbs from 33% to 37% by 2027 [4].

Here is the rub. Even with clean power growing fast, the total is growing too, so fossil fuels can still burn more in absolute terms. US power-sector carbon dioxide rose 4% last year, in the middle of a clean-energy boom, as demand and coal use both climbed [45]. A bigger clean slice of a bigger pie can still leave more carbon in the air.

The switch speeds up anyway

The move away from oil is visible on the roads. Australians bought more electric vehicles in the first six months of 2026 than in all of last year [1]. That is nearly a quarter of new car sales, as Middle East tension keeps petrol prices jumpy. In Europe, Renault’s electric models helped it fend off Chinese rivals and rebound in the latest quarter [3]. Cheaper batteries and nervous petrol prices are doing what mandates alone could not.

The heat we have already banked

While the long run looks more hopeful, the near term does not. A “super” El Nino, a periodic warming of the tropical Pacific that lifts temperatures worldwide, is developing. Forecasters give it a 90% chance of being the strongest in 150 years [59]. It is expected to peak around 3.6 degrees Celsius above average, far past the 2.75-degree record of 2015 to 2016 [59]. Berkeley Earth, the group behind the forecast, said the numbers genuinely shocked them [59].

The cost lands first on those least able to bear it. The African Development Bank warns the event could knock 10 to 20 billion dollars off African economies through drought and failed harvests [8]. Europe is already counting the dead: France recorded about 5,700 more deaths than usual during its historic June heatwave [27]. Scientists note the planet is now heating faster than at almost any point in its long past [26]. It is the speed, not the peak, that strains living things.

Oil still calls the shots

For all the clean growth, oil still moves the world day to day. Kazakhstan’s daily output roughly halved after drone attacks forced its main export terminal to close [7]. OPEC+, the group of major oil producers, is likely to raise output targets again from September [20]. Supply wobbles like these are exactly what push petrol prices around, and, this week, what nudge more Australians toward an electric car [1].

A source we are only now counting

One quieter finding is worth filing away. Researchers report natural methane seeping from beneath the North Greenland ice sheet, identified by its chemical fingerprint [56]. Methane is a greenhouse gas far more potent than carbon dioxide over the short term. It is a reminder that the carbon flowing into the air is not only ours to switch off. The more we learn about the system, the more carefully we have to count every source feeding it.

02 · Lesson · why it matters

The difference between the tap and the water

A bath fills as long as the tap beats the drain, so easing the tap only slows the rise; only closing it lowers the water.

Two true stories that seem to fight

Today carried two climate facts that sound like they contradict each other. A new study says that if we stop adding carbon, the warming stops and then slowly reverses. And yet emissions are still climbing, the heat already banked is breaking records, and a super El Nino is forming. Good news about the far future, bad news about now.

They only seem to fight. They are describing two different things: the flow of carbon we add each year, and the level of carbon already in the air. Keep those apart and the whole picture snaps into focus.

The tap and the water

Picture a bath. The tap is our emissions: the carbon we pour in, measured per year. The water in the tub is the stock already up there: the total carbon in the air, built up over more than a century. Warming tracks the water level, not the tap.

There is a drain, too. Oceans and forests pull some carbon back down. But the drain is slow, far slower than the tap has been running. So for a long time now, water has been rising in the tub.

Why turning the tap down is not enough

Here is the part that trips everyone up. Turn the tap from full to half and the bath does not start emptying. It just fills more slowly. As long as any water comes in faster than the drain takes it out, the level keeps climbing.

That is why the world can add record amounts of clean power and still see more carbon in the air. Cleaner does not mean the tap is off; it means the tap opened a little less than it would have. The level responds to the tap’s total, not its direction. A year of smaller emissions is still a year of a fuller bath.

This is the honest reason climate progress feels so slow. We measure the tap, because that is what we can change. But we live under the water.

The only thing that holds the level

So what actually stabilises the climate? Closing the tap down to the drain’s pace. When the carbon we add each year finally matches the trickle nature pulls back out, the water stops rising. That point has a name: net-zero.

And this is where today’s study matters. It looked past net-zero and asked what the water does next. Its answer: the level holds, then very slowly falls, by a fraction of a degree over centuries. The drain, once the tap is near shut, at last gets ahead. Nothing dramatic, nothing fast. But it means we are not trapped. The bath is not designed to keep rising forever. It rises because the tap is open.

One bath, and the water is old

Now notice whose bath this is. There is only one. Every country pours into the same tub, and everyone lives under the same level. A ton of carbon added in one place raises the water for all of them.

And most of the water up there is old. It was poured over decades, mainly by the countries that industrialised first. The drain belongs to no one and cannot be hurried. Yet the heat that the level makes does not fall evenly. It lands first and hardest on people who added least: the African economies facing billions in losses from a warming they did little to fill. Who got to run the tap, and who stands lowest in the tub, is not a fact of nature. It is an arrangement, built over time, and it decides who feels the water first.

Standing in the tub

The last thing to see is where we are. Not above the bath, reading the gauge. In it, water at our ankles. Our instinct says turn the tap down and the water should drop, because that is how a sink behaves when you are the only one at it. A shared tub with a slow drain does not behave that way, and no single hand on a single tap can lower the level alone.

That is the humbling part, and the useful one. The gap between the flow and the level is why good years can still feel like losing. It is why no country’s effort shows up quickly in the one number that counts. Seeing that does not tell anyone what to do. It just makes the slowness legible, and makes it harder to mistake a smaller tap for a falling tide.

03 · Lab · your turn

The Bath

Rehearse why easing the tap only slows the rise, and why the water holds or falls only once you add no more than the slow drain removes.

04 · Hope · carry this

The warming is not a one-way door. Reach net-zero and the level holds, then slowly eases back down - the bath was never built to rise forever, only for as long as we keep filling it.