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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Chinese 2,485 year tree ring study shows natural cycles control climate, temps may cool til 2068

A blockbuster Chinese study of Tibetan tree rings by Liu et al 2011 shows, with detail, that the modern era is a dog-standard normal climate when compared to the last 2,500 years. The temperature, the rate of change — it’s all been seen before. Nothing about the current period is “abnormal”, indeed the current warming period in Tibet can be produced through calculation of cycles. Liu et al do a Fourier analysis on the underlying cycles and do brave predictions as well.

In Tibet, it was about the same temperature on at least four occasions — back in late Roman times (those chariots!), then again in the dark ages (blame the collapse of industry), then in the middle ages (the Vikings?), then in modern times (blame the rise of industry).

Clearly, these climate cycles have nothing to with human civilization. Their team finds natural cycles of many different lengths are at work: 2-3 years, 100 years, 199 years, 800 years, and 1,324 years. The cold periods are associated with sunspot cycles. What we are not used to seeing are brave scientists willing to publish exact predictions of future temperatures for 100 years that include rises and falls. Apparently, it will […]

Climate helped drive Vikings from Greenland

Qassiarsuk: This is the site of the Viking settlement of 972 and unlike much of Greenland, offers relatively sheltered grazing land for sheep. Photo: John McLean. (Click to see more images of Greenland).

For the first time temperatures over the last 5,600 years have been reassembled from the inhabited area of Greenland. (Other estimates were from ice-cores that are far inland.)

William D’Andrea, the paper’s first author says: “.. we can say there is a definite cooling trend in the region right before the Norse disappear.”

7.8 out of 10 based on 4 ratings […]

The Medieval Warm Period hit west Antarctica

What do you know? The Medieval Warm Period, which either “didn’t exist” or “only happened in Europe”, also hit Western Antarctica.

Booth Island and Mount Scott are also on the Antarctic Peninsula. Photo: Stan Shebs.

The climate models don’t know why the world was warmer 1000 years ago. They don’t know why it cooled into the Little Ice Age either. The models don’t do regional projections well, and they don’t do seasonal projections with any skill, and they (in the last ten years) don’t work on short decadal timeframes either, but surely when it comes to big global temperature changes the models have got all the major forces figured out? Surely they’d be able to predict large movements across the entire globe eh? — but the first test we come to, a mere thousand years ago, shows the models have a predictive ability not significantly different from a coin toss.

Just because it was warmer 1000 years ago (due to some other reason), doesn’t mean that CO2 isn’t responsible for this warming cycle, but when all the evidence for CO2’s guilt comes only from models that can’t get the last warming cycle right, and from argument from ignorance (“Our […]

Is the Western Climate Establishment Corrupt? Part 4: Past Temperatures

The public might not understand the science, but they do understand cheating

Dr. David Evans

6 October 2010

[A series of articles reviewing the western climate establishment and the media. The first and second discussed air temperatures, the third discussed ocean temperatures.]

Click to download a pdf file containing the whole series

They Don’t Tell You: The Current Global Warming Trend is Over 300 Years Old

A Scene on the Ice by Hendrick Avercamp, circa 1600

Satellite data only goes back to 1979, and global land-thermometer records only go back to 1850. Before that we have to resort to “proxies”, which are various natural phenomena from which temperature can be deduced. As we go further back in time, the errors and uncertainties increase.

6.6 out of 10 based on 7 ratings […]

News from the Non Intergovernmental Panel on Climate Change

A sample of recent scientific news from NIPCC * The Glaciers of Greenland were smaller 5000 years ago; * African savanna trees thrive with increases in CO2; * It was hotter in China a thousand years ago, and by a whole degree; * Marine-life-with-shells can’t agree on their favourite CO2 level and * Temperatures make no difference to the 5000 year record of hurricanes. […]

Mann sues: Minnesotans say “Go ahead. Make my day”

A joint post with Baa Humbug

It’s all about audacity.

Michael Mann’s contribution to modern science may one day be remembered as the guy who made it statistically possible to get a thousand year temperature graph using any local telephone directory as a data source. (Who needs tree-rings?)

If you were a guy who’d been caught producing scientific work so inept that people could pour in random data and get the same “curve”, then you might take a satirical video on the chin (or crawl into a hole). But if you’re Michael Mann, and you also used the wrong proxy, you hid your data, used graphs upside down, and invented deceptive “tricks” to hide declines, then you might call your lawyers.

The Minnestoans for Global Warming (M4GW) made the hilariously popular Hide The Decline video, which has now been removed from YouTube. Mann claims they defamed him “by leaving viewers with the incorrect impression that he falsified data to generate desired results in connection with his research activities”. The Minnesotans said “please do”, and responded undaunted by producing a new version (see below).

10 out of 10 based on 3 ratings […]

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 […]

Unscientific hockey sticks and hidden data

These maps and graphs make it clear just how brazenly unscientific the Hockey Stick is.

It’s clear that the world was warmer during medieval times. Marked on the map are study after study (all peer-reviewed) from all around the world with results of temperatures from the medieval time compared to today. These use ice cores, stalagmites, sediments, and isotopes. They agree with 6,144 boreholes around the world which found that temperatures were about 0.5°C warmer world wide.

8.3 out of 10 based on 34 ratings […]

A simple proof that global warming is not man-made

Guest post by Dr David Evans PDF at sciencespeak.com

Now that ClimateGate has buried the fraudulent hockey stick for good, it is easy to prove that global warming is not man-made: just compare the timing of our carbon dioxide emissions with the timing of global warming.

Human Emissions of Carbon Dioxide

Emissions of carbon dioxide by humans are easy to estimate from our consumption of coal, oil, and natural gas, and production of cement:

Figure 1: Carbon emissions by humans. Source: Carbon Dioxide Information Analysis Center.

The vast bulk of human emissions occurred after 1945, during post-WWII industrialization. Half of all human consumption of fossil fuels and cement production has occurred since the mid 1970s.

7.7 out of 10 based on 37 ratings […]