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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Surprise: The Last Ice Age was colder than anyone thought. Blame CO2!

We panic about the next half degree of warming (above the 1.5 we’ve already had) but the depth of the ice age was savagely cold. For years the experts told us what Earth’s temperature was then, but apparently they were wrong.

And yet corals and rainforest survived. Plus turtles, whales, kittens — lots of things. And all without research grants.

Nice line on the Nobel gas calibration with ground temperatures. Nice proxy.

Two studies have come out in the last 10 months both showing that at its coldest point about 25,000 years ago, the Earth was on average six degrees cooler Celcius than it is today. And this new study includes estimates of temperatures of tropical land near the oceans which ought to be more stable and less prone to big extremes.

This comes from a newer style of proxy based on noble gases dissolved in ground water. It appears to be quite an accurate proxy, judging by the graph to the right. And it solves a lot of problems with other proxies. We can take samples from all around the world instead of just the polar ice caps (like we can with ice cores). […]

Extinction level event? 42,000 years ago Earths magnetic field shrank to nothing

Don’t look now, it’s a climate disaster of massive proportions and it has nothing to do with CO2.

Scientists have just discovered what they say was a wild era 42,000 years ago — where the Earth’s magnetic field practically disappeared. They’ve called it the Adams Event (after Douglas Adams of Hitchhikers Guide fame).

This was hidden previously, just before the Laschamp Excursion which we’ve known about since 1969. That event happened about 41,000 years ago – during which the Earth’s magnetic field briefly flipped. It was a pretty big deal in itself. For 800 years the field strength fell to 28% of it’s current strength and was reversed North-to-south. Due to the weak magnetic field, the theory is that cosmic rays zinged further into the atmosphere and created a layer of enriched beryllium 10 and carbon 14 which remains to this day in a thin slice around the world buried under all the layers of dirt that came after it.

The giant kauri tree log preserved in Ngāwhā, New Zealand, was alive during the Adams Event. Photo: Nelson Parker https://www.nelsonskaihukauri.co.nz/

Extraordinarily, during all this, one giant Kauri tree managed to live for more than 1,700 years. It grew […]

1970s Spock documentary — Climate scientists believe the next ice age may have already started

Watch Spock in the 1970s describing how climate scientists were predicting a mile high wall of ice that could cover Canada down to Boston “in your lifetime”, and it may already have started. Commenter Bulldust found Gary Orsum’s droll commentary on that documentary. Great stuff.

Best part begins from 5:45 mins on:

In 1977 the worst winter in a century struck the United States… one desperate night in Buffalo, eight people froze to death…

the brutal Buffalo winter might become common all over the United States. Climate experts believe the next ice age is on its way.

Temperatures have been dropping for thirty years…

With 40 years headstart on climate scares, Orsum has all the answers.

Leonard Nimoy: Arctic cold and perpetual snow could turn most of the inhabitable portions of our planet into an Arctic wasteland.

Sure says Orsum, but there are ways to allieviate that threat even with your primitive caveman technology, just get the kids to take Fridays off school.

The opening five minutes explaining how he’s not a denier though he keeps being called one. Readers here have lived that landscape already. Just say “lukewarmer” and […]

Glaciers on the move: Two minutes of extreme climate change on Swiss Alps, Italian beaches

The next ice coming to Europe might look something like the last ice age shown in this simulation. A time when Venice will be top of a long paddock that stretches to Albania.

In school children are taught to hyperventilate about the last 30m retreat of glaciers that never stayed put ever.

Instead, they could be studying this… (click to start)

At the 24,000 year BC point glaciers have wiped out Zurich, Bern, Geneva.

Image the effect on people if this were shown everytime a Swiss Alps disaster story was run?

OK, so it is a model

Advance and retreat of the Alpine glaciers during the last glacial cycle from Julien Seguinot on Vimeo.

About 25000 years ago, Alpine Glaciers filled most of the valleys and even extended onto the plains. Using a computer model that contains knowledge on glacier physics based on modern observations of Greenland and Antarctica and laboratory experiments on ice, help from traces left by glaciers on the landscape, and one of the fastest computers in the world, this animation is an attempt to reconstruct of the evolution of Alpine Glaciers in time from 120000 years ago to today.

Meanwhile, WWF […]

Fossils show models can’t predict how climate affects animals

Fossils show those dang mammals lived in all the spots they weren’t supposed to live in. Climate models don’t predict the climate, and animal distribution models don’t predict (or in this case hindcast) animal distribution either. How little we know, and how adaptable is biology?

This calls into question all the headline prophecies about the extinction of cute furry critters due to climate change.

The modelers were sure that animals would be unable to cope with temperature changes and would not have lived in the same places as they do now during a climate so different. By crikey, it was an ice age! Yet those small mammals, whose defining biology is that regulate their own temperature, flummoxed the models by living nearer the glacier sheets where the models predicted they would not live.

All the alarming forecasts of local extinctions of mammals come from assumptions built into modern models that fail in multiple ways. The temperature changes from the last 20,000 years show that these mammals have already survived massive shifts, both colder and warmer, and that anything we face in the next century is but a flea on a hippo.

In the graph, the dots are the fossils, the […]

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 […]

Carbon rises 800 years after temperatures

Ice cores reveal that CO2 levels rise and fall hundreds of years after temperatures change

In 1985, ice cores extracted from Greenland revealed temperatures and CO2 levels going back 150,000 years. Temperature and CO2 seemed locked together. It was a turning point—the “greenhouse effect” captured attention. But, in 1999 it became clear that carbon dioxide rose and fell after temperatures did. By 2003, we had better data showing the lag was 800 ± 200 years. CO2 was in the back seat.

7.8 out of 10 based on 22 ratings […]