I read three books recently , which  throw some light on how  the  developed world got itself into its present mess, and how it might get out of it.
It is important to remember that it is developed countries that have  debt problems, not the entire world. There is actually a slight surplus of saving over debt in the world, but the saving is in one part of the world and the debt is somewhere else!
Capitalism 4.0 , by Anatole Kaletsky, has  the subtitle “ The birth of a new economy in the aftermath of crisis “. As the title indicates, Kaletsky is optimistic.  He believes that most of the forces, that gave us prosperity since 1990, still exist.
The mistake we made was putting too much faith is markets, on their own.  Markets need effective Governments if they are to work.
The problem was that Governments, including Central Banks, abdicated their responsibilities after 1980, and believed that markets would naturally correct themselves. He condemns the Efficient Market Hypothesis, that underlay the mathematical trading models of many in the financial world.  By definition, models based on this hypothesis failed to predict what happened, because all the data used in the models had been collected in benign conditions.
Economics became dominated by mathematics and forgot its roots in philosophy.
 There would have been a better chance in 2006 of a philosopher, an anthropologist, or a sociologist predicting the crash of 2007/8,  that there would of a mathematical economist doing so. Indeed the IMF produced one of its most optimistic ever  forecasts for the world economy in 2006! 
Kaletsky has some pretty startling things to say about banking. We need banks, and banking is a very important activity.  Allocating savings and investment in a complex economy is a socially valuable activity and that is what banks do, and sometimes do very well. Over emphasis on “greedy bankers” and their role, while not  unjust a lot of the time, can blind us to a much more complex reality. States need banks, and banks need states. As Kaletsky puts it,
 “the taxpayer is the silent partner in every  banking business , whether in it is nationalised like  RBS, or private, like Goldman Sachs.”
And he goes on
“the idea that a purely private financial system can exist without Government backing of some kind is a market fundamentalist illusion”
He says that 
“Situations are bound to arise, perhaps once in a  generation, when  Government simply  cannot allow any bank to fail”
That said, he is highly critical of how bankers, or more precisely bank employees, are paid.
He compares the behaviour of banks in recent times, and in particular the way they awarded employees big bonuses for short term  gains, to Workers Cooperatives, run for the benefit of  employees, to the detriment of shareholders. For years,he says, banks were systematically  undercapitalised in relation to the risks that they were taking. The big losers in all of this were the bank shareholders, many of whom lost everything, and the taxpayers.
Another book, that comes to similar conclusions about the modern world, is “Obliquity, Why our goals are best achieved indirectly” by John Kay.
His basic thesis is that straight line thinking often leads us to the wrong conclusions about what to do, because it focuses almost exclusively on things we can quantify, or express in a precise way, and thus leaves out things that we sense,  in less exact ways.
If we make happiness an explicit goal of our lives, we may end up unsatisfied. But if we work for a goal outside ourselves, we may become happy as well.
Companies that remunerate employees on the basis of a few narrow measures, like enhancing shareholder value, may not even achieve high shareholder  value,  because the devalue all the other unquantifiable things that  make a company successful, like  enjoyment of working towards a goal that is socially worthwhile.
A rather more pessimistic view is taken in “Endgame, the end of the debt super cycle and how it changes everything”  by John Mauldin and Jonathan Tepper.
They believe we are heading into a second economic crisis, caused this time not by the debts of the banks, but by the debts of Governments. They fear a period of deflation, which will makes debts unsustainable, followed possibly by a period of hyper inflation,  as Governments then try to get out of their debt  difficulties by printing money.
Some of the evidence they produce is quite convincing.  Countries, like Ireland, who are borrowing on international markets, may soon find increased competition for limited funds.
The United States political system is having huge difficulty facing up to its burgeoning deficits. Already “healthcare” in the United States costs an average of 8100 dollars for every American, including the healthy ones who never get sick. Yet politicians on both sides of the divide can agree neither to raise taxes, to cut entitlements, nor take on vested medical interests.
 Japan has a Government debt of 200% of its GDP, and is able to sustain this, because it is borrowing at only 1% interest from its own people. But when more Japanese retire, and then start drawing down their savings,  Japan may no longer be able to borrow all it needs at home and will be forced to borrow on world  markets, where the  rates of interest will be much higher. That could make its debts unsustainable.
There are also property bubbles developing in China, and in Australia, where house prices are too high.
Finally there is such a thing as Austerity Fatigue.  Electorates can agree to cut back for a while, if they see a clear goal in view. But if the process is dragged on for too long, with no goal except meeting interest payments, electorates lose patience, and may make irrational decisions, as the German electorate did in 1933.
That said, we are all much more prosperous than we were in the 1930s. We are also better educated, although the German electorate of 1933 was one of the best educated of its time.
I think people need a goal that appeals to their self interest and their altruism, at the same time.  Giving a positive meaning to austerity, appealing to peoples imagination, and constantly experimenting with new low cost employment intensive  ways of  solving long standing social problems  like   energy inefficiency, the  isolation of the elderly, and  lack of locally produced food, could help  us make sense of austerity and  get us through with our sense of self worth intact.
One thing alone  is clear, the future is unpredictable, and looking for complete certainty is a waste of time!