The Termination Shock

We investigate how a well-intentioned shipping regulation inadvertently removed the planet's sunscreen, unleashing the energy equivalent of twelve atomic bombs every second.

[Speaker 1]: There is a number from 2025 that is almost impossible to wrap your head around: 23 Zettajoules. That is how much heat the deep ocean absorbed last year. To put that in human terms, imagine detonating twelve Hiroshima-sized atomic bombs every single second, twenty-four hours a day, for three hundred and sixty-five days. That is the amount of energy we added to the oceans last year. [Speaker 2]: And the terrifying part isn't just the number. It’s that 2025 was supposed to be a cooling year. We were in a La Niña cycle, which historically brings global temperatures down. Instead, the oceans broke every heat record on the books. [Speaker 1]: Today, we’re unpacking why that happened. We’re looking at the evidence that we accidentally triggered a "termination shock" by cleaning up shipping pollution-essentially ending a Faustian bargain where smog was the only thing keeping us cool. [Speaker 2]: And we’re looking at what comes next. Because now that we’ve accidentally removed that cooling pollution, a group of venture capitalists have raised sixty million dollars to sell it back to us-on purpose. [Speaker 1]: It’s Sunday, January 18, 2026, and you’re listening to The Angle. [Speaker 2]: So to understand why 2025 was such an anomaly, we actually have to go back to January 1st, 2020. [Speaker 1]: Right, the day the shipping industry changed. [Speaker 2]: Exactly. On that day, a regulation called IMO 2020 went into effect. It forced international shipping companies to cut the sulfur content in their fuel by eighty-five percent. It was a massive win for public health. Sulfur causes asthma, lung cancer, acid rain. Getting rid of it was undeniably a good thing for human lungs. [Speaker 1]: But here is the catch. For decades, that sulfur pollution had been acting as a kind of planetary sunscreen. [Speaker 2]: That’s the mechanism, yeah. It’s called the Twomey Effect. Sulfate particles from ship exhaust float up into the atmosphere and act as seeds for clouds. They make marine clouds brighter, whiter, and more reflective. Those bright clouds bounce sunlight back into space before it can hit the ocean surface. [Speaker 1]: So we had this accidental geoengineering experiment running for fifty years. We were warming the planet with CO2, but simultaneously cooling it-masking that heat-with ship exhaust. [Speaker 2]: And on January 1st, 2020, we effectively wiped off the sunscreen. We slashed those emissions. The clouds got dimmer. And suddenly, the full force of the sun started hitting the Atlantic and Pacific oceans. [Speaker 1]: Scientists call this "aerosol unmasking." But "termination shock" feels like the more accurate term for what we saw last year. Because the timing lines up perfectly. It takes a few years for the ocean system to respond, but by 2025, the mask was fully off. [Speaker 2]: And that explains the paradox of 2025. We entered a La Niña phase in late 2024. In a normal world, La Niña pushes cold water to the surface of the Pacific and cools the global air temperature. And technically, the surface waters did cool slightly in certain patches. [Speaker 1]: But the heat didn't disappear. It just went deeper. That’s where that 23 Zettajoules figure comes in. While the surface skin of the ocean looked a little cooler due to the wind patterns, the ocean heat content-the energy stored deep underwater-was skyrocketing. The underlying warming signal from the unmasking was so strong, it completely overwhelmed the natural cooling cycle. [Speaker 2]: And this has split the scientific community down the middle. We are seeing a massive debate right now about whether…