global warming and various environmental issues. Friends of Science maintains a "Climate Digest" of articles written by Ball in 2008–09. In 2007 Ball appeared on The Great Global Warming Swindle, an hour and a quarter-long British television documentary that aired on Channel 4 and that was described as a "deceptive and propagandist portrayal of the science of global warming". Also in 2007, he participated in Exposed: The Climate of Fear, a special presentation of the Glenn Beck Program, with Patrick Michaels, John Christy, and other climate sceptics. In 2010, he appeared on the Michael Coren Show. Controversies and lawsuits Ball claimed, in an article written for the Calgary Herald, that he was the first person to receive a PhD in climatology in Canada, and that he had been a professor for 28 years, claims he also made in a letter to then-prime minister of Canada, Paul Martin. Dan Johnson, a professor of environmental science at the University of Lethbridge, countered his claim on April 23, 2006, in a letter to the Herald stating that when Ball received his PhD in 1983, "Canada already had PhDs in climatology," and that Ball had only been a professor for eight years, rather than 28 as he had claimed. Johnson, however, counted only Ball's years as a full professor. In the letter, Johnson also wrote that Ball "did not show any evidence of research regarding climate and atmosphere," which Ball later admitted. In response, Ball filed a lawsuit against Johnson. Johnson's statement of defence was provided by the Calgary Herald. In the ensuing court case, Ball acknowledged that he had only been a tenured professor for eight years, and that his doctorate was not in climatology but rather in the broader discipline of geography, and subsequently withdrew the lawsuit on June 8, 2007. In 2011 climate scientist Andrew J. Weaver sued Ball over an article Ball wrote for the Canada Free Press which was later retracted. In the article, Ball described Weaver as lacking a basic understanding of climate science and stated, incorrectly, that Weaver would not be involved in the production of the IPCC's next report because he had concerns about its credibility. Andrew Weaver's defamation suit against Ball was dismissed in 2018. The judge noted that Ball's words "lack a sufficient air of credibility to make them believable and therefore potentially defamatory" and concluded that the “article is poorly written and does