Passengers wear face masks to protect against the spread of the Coronavirus as they arrive on a flight from Asia at Los Angeles International Airport, California, on January 29, 2020.

The World Health Organization has made it official: Coronavirus is the first "global health emergency" of our new era of major power competition. It will affect global markets, but also geopolitics, as well.

It's already clear that the coronavirus' impact, though too early to fully measure, will be significant on Chinese and global supply chains, markets and economies; on the legitimacy and the trust enjoyed by the Chinese Communist Party with its own people; and on Asian regional politics and U.S.-Chinese relations, where trust already was in such short supply.

So, it's not too early to contemplate the potential, unintended consequences of the virus, thought to have originated in a Wuhan wildlife wet market yet already having resulted in more than 210 deaths and more than 10,000 confirmed cases in 19 regions of China and 20 countries around the world. The cases now include the first person-to-person transmission in the United States, and a rare State Department level four advisory of "do not travel" to anywhere in China.

So even in a heavy news week during which the United Kingdom left the European Union, the United States announced a new Mideast peace plan, and the Senate advanced its impeachment trial of President Trump, none of that beats the potential of coronavirus for global impact.

The first effect, and perhaps the easiest of them all to measure, will be the hit to Chinese and other markets and economies, at a time when the world in any case was wary of a "black swan" event that might nudge it toward recession after the world economy's worst year in a decade in 2019. U.S. markets convulsed Friday, falling by more than 600 points.

The impact is all the greater as it coincides with what was already a slowing Chinese economy. It comes at a time when American and other countries' companies were already shifting supply lines from China to elsewhere due to new tariffs and trade tensions. The virus will serve as another reminder for companies to more rapidly diversify their supply chains.

Following the "phase one" trade deal with the United States, the coronavirus hit also undermines the whiff of bilateral trade optimism that had buoyed markets. It has quickly changed the narrative and increased the odds of a global market downturn in 2020. That's particularly true among emerging markets and investments in commodities from oil to copper, both down double-digits.

Should the crisis stretch out for another month, and experts now consider it more likely than not to reach well into summer, the cost could be a two-percentage point decline in Chinese growth to 4% or lower this year. First quarter growth figures in China could fall to 2% year-on-year – which would be the lowest in decades, and down from 6% in the last quarter of 2019.

The impact on the global economy will be far more significant than during the SARS pandemic of 2003, which is estimated to have provoked a global economic loss of $40 billion and a hit of 0.1% on global GDP. That's because China's share of global GDP has quadrupled since then to 16% from 4% – and fully a third of global growth has been coming from China.

Tourism markets will take an outsized hit, as about 163 million Chinese tourists in 2018 accounted for nearly a third of travel retail sales worldwide. Thailand, for example, has already reduced its 2020 GDP forecast, based on expected revenue losses of as much as $1.6 billion from 2 million fewer Chinese visitors, should travel restrictions continue for a further three months.

More difficult to calculate will be the impact of the virus on Chinese President Xi Jinping's legitimacy and that of his Communist Party.

Wall Street Journal columnist Daniel Henninger referred to a rare public apology by Wuhan's mayor, Zhou Xianwang, as "an epitaph" for the People's Republic of China. "As a local government official," said the mayor in explaining his slow response, "after I get this kind of information I still have to wait for authorization before I can release it."

Wrote Andy Xie in the South China Morning Post: "Wuhan's failure shows up the systemic weaknesses in the top-down structure of the China model, where everyone in the hierarchy is accountable to someone above."

"Though the economy will bounce back when the virus fades," writes The Economist, "the reputation of the Communist party and even of Xi Jinping may be more lastingly affected. The party claims that, armed with science, it is more efficient at governing than democracies. The heavy-handed failure to contain the virus suggests otherwise."