It's only the second time Malcolm Roberts has played the Senate estimates game, so perhaps the One Nation senator could be forgiven for not knowing all the rules.
But he received a crash course in phrasing questions from the environment department boss early on Monday.
"Do you agree that much of the strategic direction of the department is underpinned by the belief that coal-fired power stations are not clean and that their emitted carbon dioxide will cause catastrophic heating of the planet so they must be replaced by wind and solar power?" was the climate-change-sceptic senator's opening gambit.
"You've asked my opinion," department boss Gordon de Brouwer replied.
Committee chair Linda Reynolds intervened with a warning to Senator Roberts it wasn't appropriate to ask officials for their personal opinion, only questions on matters of policy or fact.
Nevertheless, the senator continued undeterred for 15 minutes, with nearly every question using the word "belief" politely batted away with an, "I think you're asking for my opinion, senator."
Senator Roberts had better luck asking how the department deals with people who say - as he does - the belief humans are causing climate change is wrong (it starts a conversation, Dr De Brouwer said) and elicited a promise he'd get copies of all the science backing up its programs.
Eventually, Senator Roberts' declaration he'd had "a deplorable response" from the chief scientist to earlier questioning used up Senator Reynolds' patience.
"I have asked several times now if you could please make sure that you're actually asking questions of the officials, not commentary or asking for a personal opinion," the exasperated Liberal senator told him.
"This is not an opportunity for an editorial, that's what the chamber is for."
