“Take Lake Baikal for instance, in Siberia: the world’s largest freshwater lake. Greater volume than all of the American Great Lakes combined and then some. Roughly twenty-two percent of the world’s surface supply of freshwater.“Now let’s say for the sake of argument that that entire lake is drained. Right down to its last gallon, yes? Well the lake’s about 5,521 cubic miles, so converting that to US gallons gives you something like 6.0793e+15… that’s fifteen zeros at the end of that figure.“And that’s just one body of freshwater, okay? We’re seeing levels dropping at Lake Victoria in Africa; the Great Lakes here in the States; Lake Titicaca in South America; massive rivers; any number of enormous man-made reservoirs.”I pause and chuckle again: “Forgive my flippancy but honestly, if you want an estimate on how much total water we’re talking about… well, choose any number that pops into your head and start adding zeros to it… many dozens of zeros.“That’s what we’re talking about.”