Some internet-surf results:
According to Wikipedia one needs approximately 6 to 7 litres milk for 1 kg milkpowder.
Assuming a consumption of half a liter of milk per human, this gives a consumption of 182 kg milk per year, which can be substituted by a consumption of approx. 30.4 kg milk powder per human per year.
According to Wikipedia (unfortunately without source) the milk powder production in Europe is 800.000 tons (per year?). A similar amount is produced in the US according to the website of the US Dairy Export Council:
Approximately 10% of the world’s milk powder production — over 800,000 metric tons — is manufactured at more than 80 plants in the United States, making the United States one of the largest milk powder producers in the world.
800.000 tons divided by 30.4 is roughly 26 million.
So if this computation is right then the annual US milk powder production would suffice for roughly 26 million people.
I couldn’t find good numbers on the soy milk production, there seem to have been some increased production in China concluding from the financial times.
Japanese people have in comparision to other asian people a rather good milk tolerance according to Gastroenterol Jpn. 1975;10(1):29-34.
Studies on the etiology of milk intolerance in Japanese adults, by Yoshida Y, Sasaki G, Goto S, Yanagiya S, Takashina K.
Eventually the US quality powder may be better then the European .
According to this german website a typical container ship takes about a month to the Far East and carries about 128.000 tons. Looking at the map it seems that a ship from the US to the Far east takes about half a month.
According to this website a cargo plane carries about 128 tons.
This post is not adressed to food speculators.