The Second Great Depression was caused by a combination of factors, the biggest one was the rise in cost of gas to put it out of reach of most people (a barrel of oil was over $250/barrel and the price at the pump was over $10/gallon).

The US, much like the first great depression, was the first hit and the worst hit. With the average person having been told they needed to own a 8mpg SUV for decades and living in the suburbs while working in city. This made a 20 mile drive to work (or back from work) cost $30, or a single trip to and from work was $60 each day. Few people could afford the drive to work and at least in the US public transport was a joke and couldn’t even attempt to make up the difference, so people lost there jobs and couldn’t find local employment.

The second major cause was related to the first. Very few things were made in the US anymore and the cost of shipping rose dramatically which in turn made prices of all goods and services rise. Even locally produced goods such as basic food stuffs had major issues being transported to stores so people could buy them. So even working people would often have insufficient money to actually buy anything. This created a spiraling rate of inflation as prices continued to rise out of control.

So few had money while the cost of anything kept increasing. This spurred a demand for charities and social safety nets, such as unemployment and social security. None of these systems could deal with unemployment as high as 50-60% and systems began to fail. The first industry to fail was the hospitals who simply couldn’t afford to take in patients anymore. Few patients coming in had health insurance as they no longer had jobs while at the same time having inheritable medical issues. The elderly were the first to die. This was especially true when the single highest issue was malnutrition which strained of social safety nets such as homeless shelters and food pantries.

These conditions would require a bit more than a decade to correct and with the entire US market taken out it dragged other nations into their own depressions. This started with the EU and Japan which were tied directly to the US economy, but was also true for other nations around the world. It was true for China, who still sold massive amounts of goods to the US, but they had the advantage of their own growing internal markets and had the smallest depression period.