I'm surprised that water is a problem given that we can economically desalinate seawater. Regarding inflation, it's not a huge problem if you're invested in assets that grow sufficiently faster than inflation (e.g., stocks, real estate, bonds - some of the time, etc.). As for population, some projections show it peaking around 10 billion before gradually falling to as little as one billion. That's a potential disaster for retirees who're counting on investment portfolios to fund their expenses. That's because fewer people means shrinking economies, less demand for real estate, negative profit growth, etc. Imo, that may be the far greater risk long term. However, it probably won't happen in our lifetime.