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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Australian Environment Conference Oct 20 2012


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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 [...]

Ocean heat content around Indonesia shows Medieval Warm Period and 2C warmth in holocene

Rosenthal et al have put out quite a humdinger of a paper. They’ve reconstructed the temperature of the water flowing out of the Pacific to the Indian Ocean over the last 10,000 years and as deep as 900m. The Indonesian Throughflow  is pretty significant in global ocean currents. There’s narrow routes for Pacific upper waters to squeeze through to the Indian Ocean through the Makassar and Lombok Straits, and via the Lifamatola Passage through the Banda Sea, and water comes in from both the North and South Pacific.

An important point in global ocean currents where the Pacific flows through to the Indian Ocean.

Points to note (assuming the study is right):

Temperatures started rising around 1700AD –  long before our carbon emissions. That temperatures were much warmer (0.65C)  in 1100AD than they were in 1950. 8,000 years ago water was 1.5 to 2 degrees warmer — isn’t that meant to be a global catastrophe? Apparently coral reefs, fish, and turtles survived.

 

Figure 4.  Holocene changes in Pacific Ocean heat content. (A) Reconstructed anomalies in Pacific OHC in the 0- to 700-m depth interval for the early Holocene, mid-Holocene, MWP, and LIA periods. Reconstructed anomalies are calculated relative [...]

The Marcott Hockey-stick: smoothing the past and getting a spike from almost no data?

The message to the world is unequivocal:

“We are heading for somewhere that is far off from anything we have seen in the past 10,000 years – it’s through the roof. In my mind, we are heading for a different planet to the one that we have been used to,” said Jeremy Shakun of Harvard University, a co-author of the study.

Source: The-world-is-hottest-it-has-been-since-the-end-of-the-ice-age–and-the-temperatures-still-rising.

There are two factors in the new Marcott paper that are major red flags. For one, there is hardly any data in the modern end of the graph. Ponder how researchers can find 5,000 year old Foraminifera deposits, but not ones from 1940? Two: they’ve smoothed the heck out of longer periods. Marcott et al clearly say there is “…essentially no variability preserved at periods shorter than 300 years…” So if there were, say, occurrences of a warming rise exactly like the last century, this graph won’t show them.

Some of the data has a resolution as poor as “500 years” and the median is 120 years. If current temperatures were averaged over 120 years (that would be 1890 to now), the last alarming spike would blend right in with the other data. Where would the average [...]

Australian sea levels have been falling for 7000 years

It’s hard to measure sea levels, because land often moves up and down too (which is known as “isostatic“). But Australia is stable tectonically, so the Australian sea-level record is more useful than most. It preserves the holocene era and the rises and falls, and correspond more with glacio-eustatic (ice equivalent) sea-level changes, rather than changes in land masses.

During the coldest days of the last ice age (known as a glacial maximum) 20,000 years ago, the oceans were 125m lower than today. They peaked at around 1 -2 meters higher than present between 9000 and 5000 years ago, and have been trending down ever since. Our current rate of 30cm/century (if that continues) hardly seems unprecedented or highly unusual. And 10% of that is apparently due to an isostatic “adjustment”. Worse, if you look at the raw data, the rate is closer to zero. Hmm. Lucky we have all those adjustments eh?

If Australian sea levels keep falling at this rate, we might really need to save That Reef.

Clearly there are many details yet to be worked out about sea-levels.

That phenomenal rise out of the ice age:

 

WA and NSW coastlines are considered the [...]

The Warmest Year Antidotes

What do you say when the Big PR bell is rung? You know the litany: “2010 was the warmest since measuring began, and the previous decade was also the warmest decade on record.” (eg The AGE)

Sure, and the world has been warming for 300 years, long before the industrial revolution. The trend hasn’t changed as our emissions rose. No one knows exactly why it started rising back then, but it wasn’t CO2. Sure and 150 years of “records” is not long. It was warmer 1000 years ago, 2000 years ago, 5000 years ago and 130,000 years ago. In fact its been warmer for most of the last 10,000 years than it is today, and it’s been warmer for most of the last 500 million years. Only people who think CO2 matters keep repeating that it’s warmed from 1850 to now without pointing out the bigger perspective. Sure, and the records have been set with thermometers like this one (next to concrete and exhaust vents — see below).  There probably weren’t too many car parks or air conditioners in 1880 either. Not to mention the non-random adjustments, and that mystery about how 75% of thermometers are ignored.

Nothing about the [...]

The big picture: 65 million years of temperature swings

Greenland 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 on [...]