We All Live in a Cheesy Submarine

 Brexit explained.

More simply, if people don't like how they are treated, they tend to leave.  This is often messy.  That's just the way breakups are.  Telling people it is wrong or stupid to leave when they don't like how they are treated is not helpful, does not typically stop them from leaving, doesn't make the relationship better, and doesn't improve anyone's understanding of what a healthy relationship looks like.  If you don't like it, you can leave.  But understand, it's probably going to be a mess and you may lose a lot in the process. 

More and more countries in the European Union are feeling unhappy with their union.  Either the union fixes its shit, or a lot more are going to leave.  Since people don't all want the same things, it is impossible to make them all happy enough to stay.  This is a problem.  Much of it is based on totally obvious mistakes that I and a few other people pointed out from the very beginning (e.g. a half-assed union is wholly doomed) while others arise from recent developments (e.g. a flood of refugees driving berserk nationalism).  Good luck fixing any of that.

The Great Dying

 ... wiped out almost all ocean life, due to oxygen deprivation.  This is fairly obvious to anyone who's ever had a bucket of minnows die on them during a warm day.  It is also a concern due to the rapid warming of oceans today.  If those die dead, we are deeply fucked.