Why are central banks buying more gold than at any time in 50 years?

http://news.goldseek.com/PeterCooper/1358781254.php

Gold bugs can hardly have missed the GFMS Gold Survey for 2012 that reported global central banks bought more gold in 2012 than at any time in the past 50 years, a net 536 tonnes of the yellow metal. The global money printers clearly know the value of the one money that they cannot create from thin air.
This is being hailed as a step by step move to a new Gold Standard. Before the global financial crisis of 2008 these same banks had an agreement to gradually sell-off their gold reserves. That has been reversed in the wake of the crisis and the money printing that has followed.
New gold buyers
The main buyers of gold are the rising powers of the East, including Central Asia and Russia, as well as Latin America. China has declared its intention to double gold consumption to 1,000 tonnes a year over the next three years while energy-rich Russia wants to exchange black for yellow gold. India is raising taxes on gold to dampen gold imports that are damaging its balance of payments.