Prime Minister Shinzo Abe will join other leaders of the Group of 20 advanced and emerging economies gathering in Germany this week, with trade and climate change expected to be high on the agenda.

The unity and relevance of the G-20 is being increasingly tested at a time when the world economy has yet to gather strong growth momentum, and as a host of global challenges, ranging from terrorism to inequality, require collective efforts.

Abe is scheduled to attend the G-20 summit from Friday to Saturday in the German port city of Hamburg, amid lingering concerns about a tilt toward protectionism that shields domestic companies by using import taxes and other measures.

With his “America First” policy agenda and calls for “fair” trade, U.S. President Donald Trump plans to join the summit, bringing into focus his remarks on trade and climate change after he pulled the U.S. out of the 12-member Trans-Pacific Partnership free trade accord and the Paris climate agreement.

“The G-20 is now loaded with confrontations and they need to talk on many levels,” said Martin Schulz, a senior research fellow at the Fujitsu Research Institute.

“Many people think the United States is turning protectionist but that is actually not the case,” Schulz said. “They want to be mercantilist, meaning they want to make money with trade and they want to export.”

After four years of negotiations, Japan and the European Union are now trying to send a signal to the world that free trade is critical, by clinching a broad agreement on a free trade deal in the run-up to the summit.

For Tokyo, such a deal will likely inject momentum into its push for free trade after disappointment among the Abe administration over the U.S. pullout from the TPP.

Japanese officials say free trade has benefited economic growth in the postwar era and that Tokyo will continue to support it.

Whether the G-20 leaders can find common ground over trade is being closely watched after their finance ministers and central bankers dropped a pledge in March to fight “all forms of protectionism,” a move widely viewed as yielding to the U.S.

In May, leaders from the Group of Seven nations — Britain, Canada, France, Germany, Italy, Japan and the United States — vowed to keep markets open and fight protectionism, although they failed to reach a unanimous agreement on climate change.

German Chancellor Angela Merkel, the leader of the host nation of the G-20 summit, has said the world has become turbulent and divided.

On climate change, Merkel described the Paris deal as “nonnegotiable,” pledging to make it a success even after the U.S. decision to withdraw.

A successor to the Kyoto Protocol, the Paris agreement to fight global warming aims to hold the world’s temperature rise to “well below” 2 degrees above pre-industrial levels and curb greenhouse gas emissions.

Trump may discuss his decision to pull out of the climate deal with his peers from the G-20, a group that expressed commitment to “strong and effective support and actions to address climate change” after the previous summit in China last year.

Bridging differences is often a tall order for the G-20, which includes China, India, and other emerging economies with diverse interests.

Still, the G-20 is widely expected to confirm the importance of using all policy tools — monetary, fiscal and structural — to make economic growth sustainable, balanced, and inclusive.

The International Monetary Fund estimated in April that the global economy will grow 3.5 percent this year and 3.6 percent in 2018.

Schulz of the Fujitsu Research Institute said the issue of inequality, particularly income disparities, has taken on greater importance amid the rise of anti-globalization.

“Income disparities are at the heart of what is happening with Brexit and what Mr. Trump is doing in the United States,” he said, referring to Britain’s decision last year to leave the European Union.

The G-20 are the G-7 plus Argentina, Australia, Brazil, China, India, Indonesia, Mexico, Russia, Saudi Arabia, South Africa, South Korea, Turkey as well as the European Union.

A flurry of bilateral meetings is expected to be held on the sidelines of the G-20 summit.

KEYWORDS climate, trade, G20