Most central banks have foreign reserves ( https://en.wikipedia.org/wiki/List_of_countries_by_foreign-e... ) and and central banks' gold reserves are typically less than 1% of their reserves. So gold backing any currency is just a small part of all gold in existence (about 170 000 000 kg ~ 7T USD)
For "all currency", the money supply is a lot (converted to USD): US M0 is 10T, UK 2.85T USD, Eurozone ~8T, Australia ~1.8T. And China, Japan, India and so on also has big monetary bases.
Most central banks have foreign reserves ( https://en.wikipedia.org/wiki/List_of_countries_by_foreign-e... ) and and central banks' gold reserves are typically less than 1% of their reserves. So gold backing any currency is just a small part of all gold in existence (about 170 000 000 kg ~ 7T USD)
For "all currency", the money supply is a lot (converted to USD): US M0 is 10T, UK 2.85T USD, Eurozone ~8T, Australia ~1.8T. And China, Japan, India and so on also has big monetary bases.