OSLO (Reuters) - The terms of Britain's future membership of the World Trade Organization will depend a lot on how it separates from the European Union, the director-general of the WTO said on Friday.

In the case of a "hard Brexit", including leaving the EU's customs union, some argue Britain can fall back onto WTO terms to govern its global trading relationships.

Britain is a member of the WTO but once it leaves the EU, the bloc's schedules of commitments -- a list of its tariffs, quotas and subsidy entitlements -- will no longer apply to Britain.

"Once they (the British) leave, legally the EU schedules no longer applies to them ... The other WTO members arguably could say: 'I don't like it. We should change this, or we should change that'," Roberto Azevedo told a business seminar in Oslo.

"A lot will depend on the terms of separation in the negotiations between the UK and the EU. That may have a positive impact on how the other WTO members view this or not.

"I don't think the global economy at this point in time can afford the luxury of more turbulence. The less turbulence we have the better. The quicker trade relations are established between the UK, the EU and other WTO members, the better."

U.S. ELECTION

U.S. presidential candidate Hillary Clinton has criticized the TPP and TTIP trade deals concluded between the United States and the Pacific nations and the EU respectively, while her rival Donald Trump has spoken out against accords such as Nafta, enabling free trade between the United States, Canada and Mexico.

Azevedo said the anti-global trade rhetoric heard on the campaign trail may make it more difficult for the next U.S. president to come back on those comments, if required.

"My concern is that if you step up your rhetoric it becomes harder and harder to backtrack," he said.

He later told Reuters: "You need to bring rationality back in the conversation about trade. It cannot be an emotional conversation."

"It is very difficult because people are affected in their everyday lives by these shifts. But these shifts are not caused by trade," he said, citing that eight out of the 10 jobs lost are due to increased productivity, new technologies, automation, rather than jobs being delocalized to countries with cheaper labor costs.

He declined to comment specifically on Clinton's and Trump's comments on global trade deals and what actions either candidates would take as president.

"We have to see who wins and what kind of policies they want to implement," he said.

(Reporting by Gwladys Fouche and Stine Jacobsen; Editing by Toby Chopra)