Updated

The relevance of the Group of 20 exclusive club of nations and Australia's place on the world stage had a lot riding on the outcome of the weekend G-20 leaders' summit in the Australian city of Brisbane.

By most accounts, the summit was a success, delivering clear, quantifiable results including a plan to boost global GDP by more than $2 trillion over five years in an effort to jolt the lethargic world economy back to life.

Experts agree that a business-as-usual result would have threatened the survival of the G-20's annual leaders' summit, which emerged from the 2008 global financial crisis as the top economic forum for responding to global emergencies but has since lost a good bit of relevance.

Mike Callaghan, G-20 Studies Center director at Sydney's Lowy Institute for International Policy, said Monday that if the G-20 fades away through lack of relevance, Australia would not deserve to have a seat on its replacement.

While Australia has ranked in recent years among the world's 13 to 15 largest economies, it has a relatively small population of 23 million and doesn't represent a wider region.

The G-20 is a collection of 19 wealthy and emerging countries plus the European Union that meets annually with six guest national leaders invited by the summit host. Critics complain that the G-20's makeup is arbitrary and that worthy countries are excluded.

Callaghan said any replacement for the G-20 leaders' summit because of recent "all-talk, no-action" complaints would likely to be a smaller group that would make decision-making more efficient while maintaining a claim to represent all major regions.

"Let's face it. We say G-20 represents nearly 85 percent of the global economy. If a couple of countries dropped out — Australia, Argentina, even Korea — we could be saying it still represents 80 percent of the global economy and it would be a smaller organization," he said.

Callaghan was among those who rated the summit a success, despite chairman Prime Minister Tony Abbott's failure to keep issues such as climate change off a purely economic agenda.

Abbott's 14-month-old government has been widely criticized for repealing a carbon tax that had been paid by 350 of Australia's worst greenhouse gas polluters for two years, and Australia had resisted pressure from countries including the U.S., China and France as well as the European Union to include climate change on the G-20 agenda.

A surprise deal between the United States and China to reduce their greenhouse gas emissions announced days before the summit, plus President Barack Obama's $3 billion pledge over the weekend to help developing countries cope with climate change, made Abbott appear to have lost control of the agenda, according to Australian media.

"Putting aside climate change, I would say it was a success because there were a lot of substantive outcomes, although they're only promises," Callaghan said.