Guest Post by Willis Eschenbach

Stuck in the Nadi Airport in Fiji for the day, waiting for my flight to Brisbane. So … I read. I found a most clearly written and fascinating article in Quanta Magazine entitled “‘Next-Level’ Chaos Traces the True Limit of Predictability“.

Basically, it seems to be Godel’s Theorem meet the Turing Halting problem.

And it seems to me that their conclusions mean that future climate states are indeed fundamentally unpredictable, but NOT for the reason usually posited, that we cannot specify the starting conditions. It’s been referred to as the “butterfly problem”, that in a chaotic system a tiny change in starting conditions can lead to huge changes in outcomes.

That issue you can kinda get around by doing a bunch of runs with different starting conditions, and by using an ensemble of a whole bunch of models … although, of course, you have no way of knowing if the starting conditions or the ensemble members have fully explored the parameter space.

But this kind of unpredictability is a brand new one. They’ve shown that even if we knew the position and motion of all the molecules in the ocean, the future state of ocean currents still isn’t predictable.

Me, I’m curious about other folks’ take on what this finding means to climate science.

Best to all from F1J1,

w.

… reminds me of an old joke. Werner Heisenberg is speeding in his car when he’s pulled over by a policeman, who asks him “Do you know how fast you were going?”

“No,” said Werner, “but I know where I was!”

PS—I’m at my mate’s house in Oz, and it’s my first time going online with SpaceX Starlink. Here’s the Ookla Speedtest results … not exactly blazing, but it works very well.