“Measuring energy demand in primary energy is about as useful as measuring nutrition in acres because it's the input to the system. And if we're enormously inefficient and we waste most primary energy, which we do, then it's similar to saying, well, Africa may have vast amounts of acres under cultivation, but it's no good if it doesn't get to people and provide the nutritional needs.”

social media, people saying, I don't understand. And those aren't, that's not, you know, and there are no fusion reactors working on Earth. And I'm like, yes, I know. Look at the footnote. And of course, all of the nuclear bros were most angry at the idea. And in fact, last year, very interestingly, both wind and solar, each individually, overtook nuclear power output. And together, they overtook gas, which I bet not many people know. If you put wind and solar together, there's more electricity produced from them than there is now from natural gas.

Well, it may, I mean, so this is something I'm thinking a lot about at the moment because of my next book, actually, which is not about the ocean, but the planet. But, you know, this sort of planetary cascade of energy, the thing that powers Earth is solar power that comes from the fusion reactor in the sky. But it trickles through the system and where you tap into it is what determines how much of it there is, basically, because of thermodynamics. But so I think these questions of, I think we're going to have to get a lot better at understanding where energy actually is and isn't and where useful energy is, which is obviously what really matters. It's not about how much energy there is. It's about how much useful energy is accessible. And those are different things.

And the clarification here for people who don't think about the physics all the time is that whenever if you get, if you get your energy by combustion, you effectively waste a lot of it as heat. That's why it's inefficient.

Two-thirds of all primary energy is, I mean, it's called waste. Waste is actually not the right word for it. It's also called rejected, because if you want to have, if you want to ride up and down your building in an elevator and you've got a lump of coal, you actually, most of the energy in the coal goes to turning a small amount of it into electricity, which actually powers the elevator. And the rest of it is, you can call it waste or they just, you can call it rejected or used up in the process of turning a bit of the energy into something useful. And it's badly misunderstood by people who really need to know better.

Well, we can have our crusade on understanding Earth as an energy cascade that we can tap into. Helen,