One area where the WUWT blog post by Mikhail Voloshin is a bit misleading is that it gives the impression that this is a recent development that is coming from the financial industry, an industry which is much more wary of the idea of being fooled by randomness, and Voloshin (and other people who have worked in the financial industry like Doug Keenan) are imparting this knowledge to the general scientific community.
The first time the random walk idea was put forward was in 1991 in this free-to-view paper called "Global Warming as a Manifestation of a Random Walk":
Matt Briggs (or William Briggs, if you prefer) wrote a blog post in 2008 about the 1991 paper and his post includes the 'R' coding or commands ('R' is a free statistical analysis program that is used by quite a few AGW sceptic bloggers) to generate random walk anomaly temperatures versus time data yourself. The whole thing can be done in one command line on R - rnorm finds a random number from a normal distribution, and cumsum calculates the cumulative sum. I remember trying out the R coding (as I had a copy of R installed on a PC), and it only takes a few trials before you get what appears to be a disturbing trend, like a rise of 3 deg C over a century.
Back in the 1970s when global cooling was in vogue, it seemed to be implicitly assumed that climate was random. Random fluctuations of temperature were going to take us into a new ice age, and it was never made clear whether this was going to be a full-blown Ice Age with extensive glaciers, or just another Little Ice Age. The first time I got the idea that climate wasn't random, and that the future climate could potentially be predicted, was from the global warming brigade in the mid 1980s when the greenhouse effect started being talked about.