US President Donald Trump, right, and Xi Jinping, China's president, greet attendees waving American and Chinese national flags during a welcome ceremony outside the Great Hall of the People in Beijing, China, on Thursday, Nov. 9, 2017. Photographer: Qilai Shen/Bloomberg via Getty Images

Editor’s Note: Myron Brilliant is executive vice president and head of International Affairs at the U.S. Chamber of Commerce. The opinions expressed in this commentary are his own.

All eyes will be on President Donald Trump and Chinese President Xi Jinping when they meet this week at the G20 summit in Japan.

The stakes couldn’t be higher. This summit offers an important chance to stave off a prolonged trade war between the world’s two largest economies, one that would throw the entire global economy into a tailspin.

Until May, US-China relations seemed on the mend. Top officials on both sides engaged in intense shuttle diplomacy and late-night trade talks. It looked like a year of tit-for-tat tariffs — which President Trump originally imposed to combat China’s forced technology transfers, intellectual property theft, market protectionism and other unfair trade practices — might soon come to an end.

But then negotiations faltered after months of progress. Both sides hiked tariffs yet again in May.

Tariffs have already hammered businesses in both nations. Total US exports to China from January through April fell roughly 21% compared to the same period last year. And costlier imports have forced US manufacturers to lay off workers to cut costs. Meanwhile, US imports from China from January through April dropped nearly 13% from the previous year.

The latest tariff hikes will prove even more painful. The taxes will cost the average US family more than $800 a year, as prices rise on thousands of products like washing machines, clothes and televisions. And by 2021, if the trade war continues to escalate, it could cost global GDP $600 billion, according to projections from Bloomberg economists.

And that’s just the short-term pain.

Over time, the economic fallout could prove catastrophic for American businesses. Nearly 1.4 billion consumers — about one out of every five people on Earth — call China home.

Walling off the Chinese market would hamstring American firms’ growth for decades to come. Many of the roughly seven million Americans whose jobs depend on US-China trade could face layoffs.

Unfortunately, tensions continue to rise as both nations penalize each other’s companies in the name of national security. China recently threatened to blacklist many companies outright. The Trump administration, meanwhile, imposed new restrictions on American companies that do business with Chinese telecom giant Huawei and supercomputing firms.

America’s national security grievances are legitimate and important. But it’d be more productive to address these concerns outside the realm of trade talks.

Further strained relations won’t benefit either country. Letting the trade war drag on will erode economic growth and eliminate jobs — leaving both nations and the world with less security and less prosperity.

The time is now — at the G20 — to redouble efforts to reach a strong, enforceable deal. The ideal agreement would expand access to Chinese markets for US exporters and investors, ensure nondiscriminatory treatment of US companies, and strengthen intellectual property protections. It would also eliminate China’s corporate subsidies and remove restrictions on digital trade and data flow.

Such a deal would lead to freer and fairer trade, support more innovation in both countries, and provide a stronger foundation to address nettlesome issues that cannot be tackled within a trade negotiation.

Prolonging the trade war would not only deprive US businesses of access to the second-largest economy, but it would also permanently alter supply chains, thereby raising costs and destroying jobs at countless US firms.

It’s up to Trump and Xi to end this mutually destructive conflict when they meet at the G20 this week.