Just not recently. CNN blares that “Scientists discover an alarming change in Antarctica’s past that could spell devastating future sea level rise”. Which is the sort of thing the scientists involved have to say when they’re looking for a grant even when what they found happened a long time ago, as in “Evidence from a 2,000-foot-long ice core reveals that the West Antarctic Ice Sheet shrank suddenly and dramatically around 8,000 years ago, according to new research – providing an alarming insight into how quickly Antarctic ice could melt and send sea levels soaring.” Of course the fact that they’ve discovered massive climate instability long before humans had any influence actually proves that, well, climate instability is normal, even if scary, so it’s foolish to assume that the most recent trivial changes prove we’re responsible, as if until now climate never changed, it just sat there cool and benevolent.

When we say “scary” we use the term advisedly. As the story notes:

“Part of the ice sheet thinned by 450 meters (1,476 feet) – a height greater than the Empire State Building – over a period of just 200 years at the end of the last Ice Age, according to the study published Wednesday in the journal Nature Geoscience.”

Though we are going to throw in our habitual “unless it didn’t”. The story blathers that:

“It’s the first direct evidence that shows such a rapid loss of ice anywhere in Antarctica, according to the study’s authors.”

But it’s not “direct evidence”. It’s a reconstruction. They didn’t get in a time machine, go back and watch. They sliced up ice cores and looked at water isotopes and air bubble pressure. So while it could be correct, it’s not yet carved in stone. Indeed, the settled science is as usual highly unsettled:

“While scientists knew the ice sheet was bigger at the end of the last Ice Age than today, much less was known about when exactly that shrinking happened, said Eric Wolff, a glaciologist at the University of Cambridge in the UK and a study author.”

We are not disparaging the creative generation and testing of hypotheses when we say that just because one paper claims to have established it more precisely, the file isn’t necessarily closed.

Naturally doom looms and it’s our fault. That part is settled:

“Now it’s clear the ice sheet retreated and thinned very rapidly in the past, Wolff said, the danger is that it could begin again. ‘If it does start to retreat, it really will do it very fast,’ he added.”

True. It might. Nature is variable. And if it did, we’d be in a heap of trouble, the soggy kind. Or at least owners of beachfront mansions like Bill Gates and Barack Obama would be. Whether it happened naturally or unnaturally, mind you. But it’s also worth noting that nothing of the sort has happened in the intervening 8,000 years so it’s not exactly an everyday occurrence.

Instead, we remind you, the same Western Antarctica seems to have been cooling for 4,000 years, as the Holocene Climatic Optimum gradually cycles downward toward the next glaciation. (Not, we carp again, “ice age”.)

Now, to repeat, when we say climate is naturally variable we do not add “so don’t worry.” On the contrary, we repeatedly emphasize the crucial importance of resilience because any sudden change, from a return of the glaciers to the melting of a major ice sheet, would strain our resources. As the story points out:

“The West Antarctic Ice Sheet holds enough water to raise sea levels by about 5 meters – more than 16 feet – which would cause devastating flooding in coastal towns and cities around the world.”

And we’d look like fools if we crippled our economies then it happened anyway.

To repeat, the situation is complex. Remember, significant warming might be happening or it might not. If it is, it might portend disaster or it might not. And if it is and it does, it might be human-caused and it might not. If it’s not, it’s silly to impose a man-made economic disaster anyway. If it is, but we’re not causing it, ditto. And if it is, and we’re causing it, but it’s too late to stop it, again, we need to gird our loins to meet it not clobber ourselves into helplessness just when we need every resource we can muster.

The authors of course say otherwise, painting a simple binary picture based on wild speculation disguised as mathematical certainty:

“The crucial thing ‘is not to test it too far,’ Wolff said, and that means tackling climate change. ‘We can avoid these tipping points still,’ he said.”

Bosh. The last one wasn’t man-made, nor was it avoidable. Which are, we say again, two separate questions. There’s also no sign of another one and, if it comes, we may very well not be able to avoid it. But instead of tackling the complexity and uncertainty, the story throws Doomsday at us:

“The study comes as scientists continue to sound the alarm about what is happening to the Earth’s most isolated continent. For example, the Thwaites Glacier, also in West Antarctica, is melting rapidly. A 2022 study said the Thwaites – dubbed the Doomsday Glacier for the catastrophic impact its collapse would have on sea level rise – was hanging on ‘by its fingernails’ as the planet warms. This new study adds to these concerns, Scambos said.”

Scambos being “Ted Scambos, a glaciologist at the University of Colorado Boulder” not connected with the study but good for a quotation on deadline. Although that 2022 study has been debunked, glaciers don’t have fingernails and natural climate variability is not proof of lack of natural climate variability even if experts say.