President Trump's outspoken dismay at China's continued trade with North Korea will make for a tense time with Chinese President Xi Jinping at this week's G-20 summit.

Following North Korea's successful intercontinental ballistic missile launch earlier this week, Mr. Trump has made it clear that his perception of China as a helpful partner is quickly deteriorating.

"The most important thing at the G-20 is the fact the U.S.-China relationship is considerably more tense," global risk consultant Ian Bremmer told "CBS This Morning" Thursday. Bremmer is founder and president of the Eurasia Group and the Harold J. Newman Distinguished Fellow in Geopolitics at the Asia Society Policy Institute.

According to Bremmer, this meeting is especially significant as it's the first time the two leaders have met in person since the U.S. has taken actions China considers against its interests, including an arms sale to Taiwan. It's also the first time since Mr. Trump has repeatedly called China out for not doing enough on the North Korea front.

"The two most important economies in the world—we thought that relationship was on a relatively calm footing, now it looks like it really isn't. That's the biggest takeaway of the G-20," Bremmer said.

Trade between China and North Korea grew almost 40% in the first quarter. So much for China working with us - but we had to give it a try! — Donald J. Trump (@realDonaldTrump) July 5, 2017

Citing a friendly encounter between President Xi and President Trump at his Palm Beach home back in April, "CBS This Morning" co-host Gayle King asked what it might take to get the relationship back on track.

"I think that Trump was in deal-making mode and 'let's see if we can get something done.' In relatively short order, he's pivoted away from that very dramatically. And I think this is not going to be an easy meeting at all between Trump and Xi Jinping. That's the body language you want to watch," Bremmer said.

On the other hand, Bremmer predicts that Mr. Trump's meeting with Russian President Vladimir Putin will be "warm and festive"—and in need of outside eyeballs.

"We want to have a lot of people in that meeting. It's important that it's not just a private bi-lat(eral) between Trump and Putin," he said. "That would inoculate Trump from a lot of the criticism he'd otherwise get."

While Bremmer thinks it would be unwise for Mr. Trump to bring up the investigation into Russia's election meddling, he does agree with the president's assessment that if Trump had appeared to be the front-runner during the campaign, President Obama probably would have more strongly addressed the hacking.

"I actually think that's an accurate analysis," Bremmer said.

Bremmer says that this G-20 is different than any other one we've seen due to a leadership void on the world stage.

"It's really not a G-20, it's a G-zero — there's an absence of leadership," Bremmer said.

Aside from the leadership deficit, Bremmer said the "elephant in the room" will be the general distrust of President Trump.

"The vast majority of these presidents do not like or trust the American president—'America First' will tell you that. And when he's not directly in front of them, you know what they're going to be talking about the entire time? Is that," Bremmer said. "All the side conversations, the leaks, and how all of these countries are going to deal with their increasing questions about the level of commitment they should have to the only superpower in the world."