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


The Skeptics Handbook

Think it has been debunked? See here.

The Skeptics Handbook II

Climate Money Paper




The nerds have the numbers on precious metals investments on the ASX



The message from boreholes

There have been suggestions that Jo Nova might be trying to hide or ignore the most recent boreholes graph from Huang et al. So here it is. This is the last 2,000 years according to 6000 boreholes, with the last 100 years also using the “instrumental record” which gives us that hockey-stick uptick at the end. Below I explain the pros and cons of this study and update my thoughts.

Huang and Pollack 2008: Their latest boreholes published study


A borehole sounds like a bit-of-a-stretch as a proxy. How could we tell if the world was warmer in 1066 by drilling a hole in the ground? Yes, fair point. But what makes boreholes useful is that they are global and there is a lot of data: specifically 6,000 holes all over the world.

I’ve been looking at boreholes in more detail, analyzing them in the light of newer proxies. When all the evidence is considered, boreholes turn out be not-much-use at giving us meaningful numbers in degrees C, and in my opinion, not-too-hot at telling us the “when” of an event either. Too much depends on assumptions.

But what are they good for is that, when combined with [...]

Great Debate Part III & IV – Glikson accidentally vindicates the skeptics!

UPDATED Part IV: Andrew Glikson replies below.

I am impressed that Glikson replied politely, rose above any ad hominem or authority based arguments, and focused on the science and the evidence. This kind of exchange is exceedingly rare, and it made it well worth continuing. Links to Part I and II are at the end. Round 4 was copied from comments up to the post.

Depending on flawed models

by Joanne Nova

May 11, 2010

For a sentence, I almost think Dr Glikson gets it. Yes, it’s a quantitative question: Will we warm by half a measly degree or 3.5 degrees? It’s not about the direct CO2 effect (all of one paltry degree by itself), it’s the feedbacks—the humidity, clouds, lapse rates and other factors that amplify (or not) the initial minor effect of carbon.

Decades ago, the catastrophe-crowd made guesses about the feedbacks—but they were wrong. Instead of amplifying carbon’s effect two-fold (or more!) the feedbacks dampen it.

Dr Glikson has no reply. He makes no comment at all about Lindzen [1], Spencer[2] or Douglass[3] and their three peer reviewed, independent, empirical papers showing that the climate models are exaggerating the warming by [...]