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). […]

Fourier Analysis reveals six natural cycles driving temperatures, no man-made effect: predicts cooling

Thermometer circa 1790

UPDATED: Post note below, with a couple of extra caveats…

Lüdecke, Hempelmann, and Weiss found that the temperature variation can be explained with six superimposed natural cycles. With only six cycles they can closely recreate the 240 year central European thermometer record. There is little “non-cyclical” signal left, suggesting that CO2 might have a minor or insignificant effect.

The three German scientists used Fourier analysis to pick out the dominant cycles of one of the longest temperature records we have. The Central European temperature is an average of records from Prague, Vienna, Hohenpeissenberg, Kremsmünster, Paris, and Munich.

The dominant cycle appears to be about 250 years. There is also a cycle of about 60 years, corresponding to the Atlantic/Pacific decadal oscillations.

Data is of course, always the biggest problem. If we had 10,000 years of high quality global records, we could solve “the climate” within months. Instead, we have short records, and Lüdecke et al, make the most of what we have. The European records are only 240 years long, or (darn) one dominant cycle, and only one region, so to check that the results are valid over longer periods they also analyze a the 2000 […]

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 […]