Richard Muller, converted climate change sceptic, still a maverick

Tomorrow, the University of Hong Kong will host a lecture by one of the most colourful characters in climate science, Richard Muller. The US physicist is perhaps most famous for his "conversion", announced in July, from being a sceptic to a proponent of the reality of climate change.

The Berkeley (University of California) professor heads the Berkeley Earth Surface Temperature (Best) project, which has found that the long gradual temperature change over 250 years is an excellent match to our record of greenhouse gases, and concluded that virtually all of the warming of that period was caused by humans.

Though he obtained his PhD in elementary particle physics, Muller's research interests span astrophysics, including the cosmic microwave background and supernovae, along with aspects of geophysics. He has espoused a theory that our sun is partnered by an undiscovered small star he calls Nemesis, "the death star". Muller has written a historical novel, The Sins of Jesus ("he slowly slips deeper and deeper into sin") and a short essay titled "Why Dumbledore is Gay" - on the headmaster of fictional wizarding school Hogwarts. Muller even opened a restaurant; you won't be surprised that the cuisine was "eclectic".

Muller has a particular appeal as a climate scientist, as he formerly expressed doubts about methods and results, and is now a self-confessed "converted sceptic". In 2004, he wrote of a discovery that hit him like a bombshell: two sceptics had produced an analysis purportedly showing the "hockey stick" - a graph with temperatures long steady then suddenly rising in recent years - was an artefact of poor mathematics. "How could it happen?" asked Muller.

In 2010, Muller and his daughter Elizabeth established the Berkeley Earth project in order to take an independent look at temperature data. Sponsors included the Charles Koch Foundation, established by one of the two billionaire Koch brothers known for sponsoring denial of climate science and supporting Republican politicians. Anthony Watts, an ex-television-weatherman and energetic blogger on global warming denial, predicted "the BEST result will be closer to the ground truth that anything we've seen".

Last year, Muller testified before the United States Congress on the project's initial findings. "We confirm that over the last 50 years, temperature has risen 0.9 degrees Celsius, or 1.6 degrees Fahrenheit," he announced. "This is the same number that the IPCC [UN Intergovernmental Panel on Climate Change] says."

Though the results are yet to be published in a scientific journal, they have attracted considerable media interest, and this summer Muller wrote in The New York Times that he was going a step further and concluding humans are almost entirely the cause of the warming.