Each December for the past fifteen years, the literary agent John Brockman has pulled out his Rolodex and asked a legion of top scientists and writers to ponder a single question: What scientific concept would improve everybody’s cognitive tool kit? (Or: What have you changed your mind about?) This year, Brockman’s panelists (myself included) agreed to take on the subject of what we should fear. There’s the fiscal cliff, the continued European economic crisis, the perpetual tensions in the Middle East. But what about the things that may happen in twenty, fifty, or a hundred years? The premise, as the science historian George Dyson put it, is that “people tend to worry too much about things that it doesn’t do any good to worry about, and not to worry enough about things we should be worrying about.” A hundred fifty contributors wrote essays for the project. The result is a recently published collection, “What *Should* We Be Worried About?” available without charge at John Brockman’s edge.org.

A few of the essays are too glib; it may sound comforting to say that ”the only thing we need to worry about is worry itself” (as several contributors suggested), but anybody who has lived through Chernobyl or Fukushima knows otherwise. Surviving disasters requires contingency plans, and so does avoiding them in first places. But many of the essays are insightful, and bring attention to a wide range of challenges for which society is not yet adequately prepared.

One set of essays focusses on disasters that could happen now, or in the not-too-distant future. Consider, for example, our ever-growing dependence on the Internet. As the philosopher Daniel Dennett puts it:

We really don’t have to worry much about an impoverished teenager making a nuclear weapon in his slum; it would cost millions of dollars and be hard to do inconspicuously, given the exotic materials required. But such a teenager with a laptop and an Internet connection can explore the world’s electronic weak spots for hours every day, almost undetectably at almost no cost and very slight risk of being caught and punished.

As most Internet experts realize, the Internet is pretty safe from natural disasters because of its redundant infrastructure (meaning that there are many pathways by which any given packet of data can reach its destination) but deeply vulnerable to a wide range of deliberate attacks, either by censoring governments or by rogue hackers. (Writing on the same point, George Dyson makes the excellent suggestion of calling for a kind of emergency backup Internet, “assembled from existing cell phones and laptop computers,” which would allow the transmission of text messages in the event that the Internet itself was brought down.)

We might also worry about demographic shifts. Some are manifest, like the graying of the population (mentioned in Rodney Brooks’s essay) and the decline in the global birth rate (highlighted by Matt Ridley, Laurence Smith, and Kevin Kelly). Others are less obvious. The evolutionary psychologist Robert Kurzban, for example, argues that the rising gender imbalance in China (due to the combination of early-in-pregnancy sex-determination, abortion, the one-child policy, and a preference for boys) is a growing problem that we should all be concerned about. As Kurzban puts it, by some estimates, by 2020 “there will be 30 million more men than women on the mating market in China, leaving perhaps up to 15% of young men without mates.” He also notes that “cross-national research shows a consistent relationship between imbalanced sex ratios and rates of violent crime. The higher the fraction of unmarried men in a population, the greater the frequency of theft, fraud, rape, and murder.” This in turn tends to lead to a lower G.D.P., and, potentially, considerable social unrest that could ripple around the world. (The same of course could happen in any country in which prospective parents systematically impose a preference for boys.)

Another theme throughout the collection is what Stanford psychologist Brian Knutson called “metaworry”: the question of whether we are psychologically and politically constituted to worry about what we most need to worry about.

In my own essay, I suggested that there is good reason to think that we are not inclined that way, both because of an inherent cognitive bias that makes us focus on immediate concerns (like getting our dishwasher fixed) to the diminishment of our attention to long-term issues (like getting enough exercise to maintain our cardiovascular fitness) and because of a chronic bias toward optimism known as a “just-world fallacy” (the comforting but unrealistic idea that moral actions will invariably lead to just rewards). In a similar vein, the anthropologist Mary Catherine Bateson argues that “knowledgeable people expected an eventual collapse of the Shah’s regime in Iran, but did nothing because there was no pending date. In contrast, many prepared for Y2K because the time frame was so specific.” Furthermore, as the historian of ideas Noga Arikha puts it, “our world is geared at keeping up with a furiously paced present with no time for the complex past,” leading to a cognitive bias that she calls “presentism.”

As a result, we often move toward the future with our eyes too tightly focussed on the immediate to care much about what might happen in the coming century or two—despite potentially huge consequences for our descendants. As Knutson says, his metaworry