Australian Prime Minister Malcolm Turnbull has inherited a hard-right climate-change skeptic for his deputy after the retirement of his current No. 2 on Thursday, an appointment that could block any revamp of an emissions trading scheme.

Agriculture Minister Barnaby Joyce, an outspoken lobbyist for farmers and for tougher controls on foreign investment, was voted to lead the coalition government's minor partner, the Nationals, in Canberra late on Thursday. The leader of the Nationals traditionally takes the job of deputy prime minister.

"We will likely see a more assertive Nationals under Barnaby," said University of Sydney political scientist Rod Tiffen. "He and Turnbull really have very opposing views on climate change and they will butt heads over this."