I understand the term perfectly well, and the carrying capacity of the earth is at least 15 perhaps 20 billion. Currently we produce more food that we can consume. The problem is we distribute it rather badly.
In terms of water, we wast so much of it, that this is not really a problem. Call me back when we have ripped out our lawns, moved to high efficiency European washing machines, 1 gallon toilets, drip irrigation, etc. Then I'll believe your claims of water shortages.
Just because Ehrlich was wrong doesn't mean we aren't facing a crisis.
Ah crisis, the most over used word of the environmental movement. Everything is a crisis. Ebola is a crisis of a million dead with an actual final tally of thousands, rape on campus (which happens at lower rates than elsewhere) is a crisis, water "shortages" are a crisis even though Israel seems to manage fine (though not without trouble and ingenuity), population is a crisis even though most countries are moving rapidly towards below replacement fertility levels .