We are in unprecedented times in case there's any doubt the amount of debt the world has right now has never been this much, ever. Public debt is very high in the euro zone, Japan and the US and private debt is at record levels all around the world.
Public Debt
Back in August 04 2011 Fox News published an article explaining that the US public debt was then $14.58 trillion which is equal to the GDP of the entire US economy and approximately 1/3 of the global GDP.
How big is the debt per head?
14.58 trillion dollars (100% of US GDP )equates to approximately 47k per US citizen or 135k per US taxpayer. source http://www.usdebtclock.org/
How does this compare Worldwide?
Looking at the Public debt in comparison to other countries from wikipedia. There is also another site with a view of some this information over time by country
How Does it compare over time?
Looking at the debt over time the graph below ends in 2009 but if you drew it out to 2012 with a GDP to debt percentage of 100% you would see that the US debt is the largest it has been since WW2. From wikipedia.
How does the debt compare to other Countries?
UK
Current UK debt is running at about 70% of GDP which is the highest it has been since 1965. source http://www.ukpublicspending.co.uk/debt_brief.php
Australia
Currently the debt is running at $112 billion (16k per person). source http://www.debtclock.com.au/.
2011 GDP is $925 US bn which equals 27% of GDP
Others
Greece's debt is 143% of GDP
Ireland 's debt is 112% of GDP
EU (2010) debt is 82.31% source wikipedia
Japan 205%
What About Private Debt?
Private debt is otherwise known as consumer or personal debt and is very significant.
United States
US government debt is at its highest it has been since the second world war. Private debt has never been as large as it is today
The chart above shows that public debt in the US is 320% of GDP in 2011. According to wikipedia in 2011 US private debt was $50.2 trillion (The global GDP). This means that in total US debt is around 420% of US GDP. As far as other countries go private debt is not as high as the US but in most cases it is an all time high.
UK
This figure was around 400bn in 1993 it is now 150bn
Others
Below is a chart that gives personal debt to income by country
Global Debt
So in conclusion debt levels have never been this large, ever.