CHINA ISN'T THE ONLY THREAT FACING THE GLOBAL ECONOMY IN 2016.

Billionaire investor George Soros had an ominous warning for the world on Thursday: A 2008-style financial crisis is brewing.

The main culprit, in his view, is China. Given Soros' reputation as a savvy trader and the turmoil in global markets right now, many investors would be inclined to agree with him. 

Chinese stock markets have fallen sharply this week, plunging more than 7 percent on Monday and Thursday and twice triggering new so-called circuit-breakers, which are designed to calm investors but have instead sparked a sell-off in financial and commodity markets around the world.

The catalysts were weak manufacturing data and Beijing’s decision to further reduce the value of the yuan to an almost six-year low, which have deepened concerns about the strength of the world’s second-largest economy and raised the prospect of a currency war with other emerging markets.

Markets “are in a panic over what’s happening in China,” Derek Halpenny, European head of global markets research at Bank of Tokyo-Mitsubishi UFJ in London, told The New York Times.

“People are saying, ‘Whoa, growth is way worse than we were expecting this year.’”

Soros suggested the Asian powerhouse was in crisis.

“China has a major adjustment problem,” he told an economic forum on Thursday, according to Bloomberg.

“I would say it amounts to a crisis. When I look at the financial markets there is a serious challenge which reminds me of the crisis we had in 2008.”

The concerns about China are not new. Since the huge sell-off in Chinese stocks last summer, investors have been fretting that Chinese policymakers’ attempts to kick-start economic activity were not working and that ongoing efforts to devalue the currency were a sign that Beijing had, to put it bluntly, run out of ideas — and was willing to risk the wrath of its trade partners in order to boost its exports.   

Given the size of the Chinese economy and its importance in global trade and investment, investors are rightly worried about its slowdown.

But if another financial crisis were to erupt this year, China wouldn't be the only trigger.

Here are four other issues that are keeping investors awake at night.

1. US interest rates

BRENDAN SMIALOWSKI/Agence France-Presse

The Federal Reserve’s decision in December to raise interest rates for the first time in almost a decade has huge consequences for the rest of the world, particularly emerging economies. South Korea, Mexico, Turkey and Brazil are on a long list of countries that have seen their currencies weaken as investors boost their holdings of dollar-denominated assets to profit from the relatively higher interest rates in the United States. A stronger dollar can make their imports more expensive and fuel inflation. Higher borrowing costs also affect the dollar-denominated loans taken out by companies by making them more expensive to pay back. “Economic collapse” in emerging economies is a risk this year, UC Berkeley’s Barry Eichengreen told the Atlantic.

2. Falling commodity prices

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Crude oil prices are at multi-year lows, which is great for American car owners who are enjoying cheap gasoline, but worrying for the global economy. One of the main reasons for the weakness is a global glut — the world is producing more oil than it can consume. A slowdown in China’s energy-guzzling economy has eroded demand, but so has the stronger dollar, which makes commodities priced in the greenback more expensive for traders using other currencies. OPEC members' refusal to cut production isn't helping, either. That’s forcing oil producers to slash capital expenditure and lay off workers. It's also hurting countries that rely heavily on oil revenues to keep their economies operating, such as Russia and Mexico.

And it’s not just oil. The price of iron ore, which is a key ingredient in steel, is also trading at its lowest level in years, while the copper price is at a near seven-year low. 

More from GlobalPost: Uh oh, copper has fallen to its lowest price since the financial crisis

3. European economic weakness

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European policymakers are still struggling to get the euro zone economy back on its feet. Very low inflation persists, and economic growth has been weak (although there were signs of a pick-up toward the end of 2015), despite their efforts to revive the region. As the Federal Reserve tightened interest rates in December — a move that reflected a strengthening of the US economy — the European Central Bank was cutting interest rates and leaving the door open to further monetary policy easing if required. The latest inflation data for the single currency area, a lackluster 0.2 percent in December, suggests it will be.

4. Brazilian disaster

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Brazil, the largest economy in Latin America, faces a "political and economic disaster," the Economist predicted at the beginning of 2016. As the country prepares to host the Olympic games in August, its economy is sinking deeper into recession, its public finances are in tatters, and the country is wracked by political instability. An ongoing corruption scandal involving the state-owned oil giant Petrobras and top government officials is erasing whatever faith Brazilian voters still have in their leaders. In addition, President Dilma Rousseff is fighting efforts to have her impeached.