What are the main problems that may arise if all countries close (or almost close) their borders for 1-2 years or more?
Fortunately, it cannot be said that some kind of isolation is felt now, because we can easily call (Skype) a person who lives in another country.
But what problems can arise?
Majority of the countries relies to other countries for their basic needs like oil, rice and flour, countries will suffer if the border and the trade in are close, of course some big city also relies revenues coming from tourist, so it's going to be a big blow for them if every country close their borders, we cannot last this long, because we need each other help.