It’s now more than 10 years since the subprime mortgage crisis in the U.S. forced banks around the world to stop lending to each other as fears rose over the unknown quality of balance sheets.Within months, factory output and trade collapsed, forcing unemployment to rise quickly.While central banks and lawmakers acted to oil the wheels of finance, the recovery has been fragile and expensive. The prospect of another global recession is real with obvious economic slowing in the U.S. and the largest economies of Europe and Asia.CNBC looks at some of the situations around the world that could soon create yet more political and financial stress.A slowdown in the US economyBrendan Smialowski | Getty Images”When America sneezes, the world catches a cold,” so the saying goes. And as the effects of a President Donald Trump’s $1.5 trillion tax overhaul begin to tail off, the U.S. economy is showing signs of a sniffle.From April to June this year, business investment fell by 1% when compared to the same quarter in 2018. Additionally, consumer confidence slumped by the most in nine months in September. Expectations among consumers for the short-term outlook also fell sharply in the same month.Then came a data set that made everyone sit up and take notice. One gauge of U.S. factory activity suggested that manufacturing had dipped to its lowest level in 128 months. That number appeared to trigger an 800-point loss on the Dow Jones Industrial Average over two days. Corporate profits are stumbling too. The S&P 500 as a whole reported a fall in earnings in both the first and second quarters of 2019.The Fed now expects growth this year, as measured in U.S. gross domestic product (GDP), to come in at 2.2%, well below the Trump administration’s long-held 3% target.Countering the argument are robust retail sales in the United States which continue to exceed forecasts as well as historically high levels of employment and disposable income.For the White House to hit its headline economic target as it heads into an election year, it will hope that any fear of the future is outweighed by the American consumer’s continued desire, and ability, to spend.China’s debt pile blows upWorkers labor on a construction site for a residential property in Wuhan, China.Tomohiro Ohsumi | Bloomberg | Getty ImagesChina has fueled its economy by loading up on debt and the numbers have gotten breathtakingly large. The Washington-based Institute of International Finance (IIF) has estimated that in the first quarter of 2019, the total amount of corporate, household and government debt in China hit an eye-watering 303% of GDP.The report said Beijing’s attempt to rein in non-financial corporate debt had been rather defeated by borrowing in other sectors which had brought China’s total debt pile to more than $40 trillion.China has said time and again that its borrowings are manageable, but policy levers are hampered by the risk that choking off further debt could accelerate the slowing of economic growth that is already underway.Moody’s ratings agency confirmed China’s A1 debt rating in July this year but warned: “Episodes of financial stress for some local banks or state-owned enterprises (SOEs) are likely to continue to test the capacity of the central and regional governments to prevent contagion.”Over the last decade, China has accounted for about one-third of global growth each year. Any hard landing for the economy would immediately sound alarm bells in other parts of the world and investors would rush to protect assets.Andy Rothman, an investment strategist at Matthews Asia, said in March that Chinese debt is “a serious problem” but is unlikely to run the risk of a hard landing or banking crisis.Rothman said that while China’s main problem is corporate debt, which has steadily risen since the 2008 global financial crisis, most of the borrowings were taken out by state-owned enterprises from state-run banks.Hong Kong protestsRiot police detain a woman as anti-government protesters gather at Sha Tin Mass Transit Railway (MTR) station to demonstrate against the railway operator, which they accuse of helping the government, in Hong Kong, China September 25, 2019.Tyrone Siu | ReutersPublic unrest in Hong Kong has been going on for more than four months. It began with the aim to oppose powers which could have seen Hong Kong authorities extradite fugitives to mainland China, but has now morphed into wider demands from citizens who want property reform and fear the strengthening hand of Beijing.Violence and loud protest have horrified onlookers and it seems there is little chance that Hong Kong Chief Executive Carrie Lam has the voice to quell the anger.Hong Kong is an essential hub for financial activity and trade. The Bank for International Settlements has calculated that the city oversaw $437 billion in foreign exchange transactions in 2016. It is also a huge export source — delivering merchandise all over the world from its port.The finance center also acts as one gateway in and out of the Chinese economy with banks based there funneling capital from international investors. Continued civil unrest could, therefore, affect economies all around the world as trade is disrupted and investments seize up.Western firms may also think again about basing employees or deploying capital in Hong Kong, especially following the vivid example of Cathay Pacific. Under pressure from Beijing, the airline’s chief executive was forced to resign after it was found that employees, including pilots, had been active in the protests.Should China decide it has to tighten its grip further then the future of the “one country, two systems” arrangement in place since 1997 could be called into question. That might drag the United States into the fight as it has legally promised to treat Hong Kong separately from mainland China for matters concerning trade and economic policy.Contagion from ArgentinaAlberto Fernandez at a polling station during the Primary, Open, Simultaneous and Mandatory elections (PASO), in Buenos Aires, Argentina, on 12 August 2019. Argentines vote for pre-candidates to be defined in the general elections of October 27.Anadolu Agency | Anadolu Agency | Getty ImagesAt the beginning of 2019, the renowned emerging markets investor Mark Mobius announced his firm was staying away from Argentina.”Quality of life has declined; education levels have gone down, and we are not happy with the macroeconomic situation yet. There has been a lot of pain and people can only take so much.”Mobius said he would look again only if then President Mauricio Macri could get a strong mandate in upcoming elections. The primary vote came in August, Macri lost heavily, and the market followed Mobius out of the door.Argentina’s stock market plunged more than 30% in the days following that shock result. According to one data set, it was the biggest stock market index fall in any country since 1950. In the immediate hours following the surprise poll, the peso shipped 15% of its value versus the U.S. dollar.This will make dollar-denominated loans more expensive. The country has $80 billion worth of debt due in 2019 and 2020 — raising the prospect that the country could default on investor debt for the third time in less than 20 years.The country is to impose currency controls until the end of 2019 to inhibit losses and wants the International Monetary Fund to relax debt payments.Andrea Iannelli, investment director at Fidelity International, told CNBC in August that he expected “a spillover (or) contagion of some sort,” into other countries.Aberdeen Standard Investments is also bearish on Argentina and have reduced exposure.”We think pretty big challenges remain in Argentina and some sort of a debt extension is inevitable,” said the firm’s head of global emerging market debt, Brett Diment.The fall of Trump’s ‘favorite dictator’Donald Trump, Melania Trump, King Salman bin Abdulaziz al-Saud and Abdel Fattah el-Sisi put their hands on an illuminated globe during the inauguration ceremony of the Global Center for Combating Extremist Ideology in Riyadh.Bandar Algaloud /Saudi Royal Council/Handout | Anadolu Agency | Getty ImagesLast month, various worldwide media outlets reported demonstrations against the Egyptian government in several cities including Alexandria and the capital Cairo.Demonstrations in Egypt have been illegal without government approval since 2013 when President Abdel Fattah el-Sisi led a military coup against the Muslim Brotherhood’s Mohamed Morsi. Morsi died during his trial in June this year.The protests had a direct effect on Egypt’s EGX 30 stock market, causing an 11% slump that wiped out all gains accumulated in 2019, as investors appeared to take their profits and run.Goldman Sachs analyst Farouk Soussa said in a September note that the negative impact on Egyptian risk assets could be more sustained should the political instability continue.State Department figures reveal U.S. direct investment in Egypt was $21.8 billion and, on the surface, relations between the two countries have recently improved. President Donald Trump is reported to have asked “Where’s my favorite dictator?” when waiting to meet Sisi at the G-7 summit in August.Sisi has also been strengthening ties with neighboring Saudi Arabia. Any attempt to remove him would likely lead to a heightening of tension, at least in the short term, between Riyadh and Cairo. Oil traders will be keeping a keen eye.