JoNova

A science presenter, writer, speaker & former TV host; author of The Skeptic's Handbook (over 200,000 copies distributed & available in 15 languages).


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Now that was “climate change” 8200 years ago — California lashed by 150 years of storms

Don’t tell me that cold is nice and the climate was ever ideal

A few scientists thought that the climate was stable and well behaved during the Holocene until we invented coal power and the Ford Model T and everything fell apart “unprecedentedly”.

But 8200 years ago things apparently got pretty wild. See the GISP graph below where there was a three degree fall in temperatures suddenly (circled in red below). A new study found that at the same time China and California also cooled. Strangely, this cooling effect probably did not produce calm, happy days for the Californians at the time. Instead it looks like they got 150 years of intense winter storms and a lot of wet weather.

UPDATE: This graph shows the ice-core data up until 1855. The last 150 years (1705 to 1855) are highlighted in red to show the warming as the Earth began coming out of the LIA. Obviously that red line would continue up further if it was drawn to the present.

Looks like real climate change….

The reason for the sudden snap is possibly that a couple of massive glacial lakes in North East America collapsed and suddenly drained out [...]

Greenland ice cores show natural swings are large and warming means less storms

A new high resolution ice core in Greenland surprises even me with the wild swings and detail. The authors are discussing wind direction and storms that occurred in specific years 12,000 years ago, which is extraordinary information if accurate. They use elements like sodium (from sea salt) to figure out how many storms have dumped salt on the ice and take bands so thin they identify each summer so long ago*. The slices are so thin, they claim to have hundreds of samples per year.

The message here is that the cold younger dryas period ended abruptly (within one year) and so did the storms. Naturally, they warn that the abrupt changes mean the climate is unstable, “be afraid” type stuff. My take on this is that if natural factors cause abrupt climate change, we need to know what those natural factors are. The obsession with CO2 is hindering that. Also if warming brings less storms, that’s probably not such a bad thing. The caveats being that this is only one site, and less storms over the GISP site doesn’t tell us if less storms occurred elsewhere. It could be that jet streams shifted and moved the storms to another [...]

The big picture: 65 million years of temperature swings

Greenland Interglacial Temperatures – last 10,000 years. Are we headed for an ice age? (See below for more detail.)

David Lappi is a geologist from Alaska who has sent in a set of beautiful graphs–including an especially prosaic one of the last 10,000 years in Greenland–that he put together himself (and which I’ve copied here at the top).

If you wonder where today’s temperature fits in with the grand scheme of time on Earth since the dinosaurs were wiped out, here’s the history. We start with the whole 65 million years, then zoom in, and zoom in again to the last 12,000 from both ends of the world. What’s obvious is that in terms of homo sapiens history, things are warm now (because we’re not in an ice age). But, in terms of homo sapiens civilization, things are cooler than usual, and appear to be cooling.

Then again, since T-rex & Co. vanished, it’s been one long slide down the thermometer, and our current “record heatwave” is far cooler than normal. The dinosaurs would have scoffed at us: “What? You think this is warm?”

With so much volatility in the graphs, anyone could play “pick a trend” and depending [...]