One of the points in the paper is that the flame of the burning of this gas is relatively cold, 130°C, which is consistent with what Bob Greenyer measured with the Optris, albeit I don't know how the guys that report that temperature that King quotes performed the measurement (I e-mailed them asking, hope they answer).
The reference for the 130 C is  this website , unless there is another 130 C mentioned.
The website reference seems to be regarding the torch tip temperature, not a flame temperature. The website comment is correct that the BG flame radiates very little heat.
Later I found the same reference  above repeated , but also  is referenced for 130 C, found here . The first sentence of the report mentions George Wiseman, owner of the website above, and is therefore likely the source of the 130 C (134 C) temperature again.