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I'm skeptical of most economic forecasts, because nearly all of them will end up wrong. "We really can't forecast all that well," former Fed chairman Alan Greenspan said last year. "We pretend that we can, but we really can't." 

Still, a few things seem inevitable. 

The person who figures out cheap, mass-scale desalination will win the 21st century. There's too much evidence that water scarcity is becoming a problem, and too much logic that desalination is the solution.

People will need to work longer. Seventy-five is the new 65. A 25-year old female with a bachelor's degree can now expect to live to age 85. If you expect to retire at 65, that means spending almost a quarter of your life with no work income. Given how little we're willing to save, that's just not going to work. I like Carlos Slim's proposal: Rather than working nine-to-five, five days a week until your 60s, more workers should work in 11-hour shifts, three days a week, and plan to work well into their 70s.

There will be a big shift in cultural norms once millennials are old enough to dominate political office. Just look at how they feel about religion, gay marriage, and marijuana, to name a few. Max Planck said science accepts a new truth "when its opponents eventually die, and a new generation grows up that is familiar with it." Same with social norms. Like it or not, you can see exactly where it's going.

Internet comment sections will die. For every civilized article comment there are dozens of vicious, off-topic rants that highlight society's struggle to differentiate between "your" and "you're." This isn't harmless, as Anne Applebaum of Washington Post pointed out: Multiple studies show that anonymous comments change the way people interpret the news. That's dangerous. Several publishers, from Popular Science to the Chicago Sun-Times, have shut down their comment sections. Others only allow vetted comments. I think we'll see more of this in the future. At a minimum, comments will have to be connected to a Facebook account, ending anonymity.

Enormous energy will be devoted to small risks, while huge risks will be ignored and written off. This is just how history works.

Humility will be the most admired trait; vanity the most common. This is just how people work.  

Yellow cabs and radio stations will crumble. Uber has already caused San Francisco Yellow cab rides to fall 65% in the last two years. That will continue. Streaming music services like Spotify will do the same thing to radio stations. Radio is 1920s technology competing with Stanford computer geeks. After trying Spotify, I haven't used my car radio in months. This trend will continue, and ad sales for radio stations will shrivel just like it did for physical newspapers.

Financial fees will plummet; service will improve. "Financial transactions are just numbers; it's just information," venture capitalist Marc Andreessen wrote recently. "You shouldn't need 100,000 people and prime Manhattan real estate and giant data centers full of mainframe computers from the 1970s to give you the ability to do an online payment." Same for investing advice. One-percent management fees from financial advisors will shrivel as companies like Betterment and Wealthfront prove their worth. Flat fees will become more popular. Twenty years from now, we'll look back baffled at how cavemen in New York could make $800,000 for pushing numbers around.

College tuition growth will slow. It already has, actually. A lot of the reason college tuition spiked during the last two decades was to make up for a surge in grants and scholarships, causing wild price discrimination. My guess is that trend will reverse, and to gain a rare PR win, schools will cut tuition, but make up for it with fewer scholarships.

At least one company that is currently one of the largest and most admired in the world will be exposed as a giant fraud. I don't know which one, but this seems inevitable in a capitalist system where the rewards for success are so high.

Pessimism will overshadow progress. Twenty years from now, someone will be sitting in his or her self-driving car on the way home from a doctor's appointment that miraculously cured a disease that's currently a death sentence, and will be complaining about how awful the world is. It's always this way. The odds are incredibly high that the average American will have a higher standard of living 20 years from now; yet, we'll look back at untold numbers of books and articles lamenting that everything sucks. Few will notice how much progress we've made because it happens slowly; but they'll pay attention to the doom forecasts because they are repeated day in, day out. 

You can keep your shoes on at airport security. Pre-check will become the new normal, driven by frustration and a diminishing sense of fear, as 9/11 begins to feel like ancient news.

Median wages will rise. Paying workers so little that they're sick, stressed, worried, unproductive, and constantly looking for new work isn't good for business owners. A point will come where raising wages will be the best way to maximize profits. I suspect we're getting close.

The most important news story of the next 20 years is something nobody can even contemplate today. I don't think there's ever been a time in history when this wasn't true.

Everything else is a crapshoot.

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