Predictions beyond 2100 are fiction

In my Quilllete article on climate change, I briefly discussed the usefulness—or rather, uselessness—of trying to discover what might happen in hundreds or thousands of years. Those time scales literally do not belong to the foreseeable future. Trying to predict so far into the future is hubris. The recent example of this folly was the “Hothouse Earth” scenario, which prompted me to write:

This attention to the distant future shows that the question “what is the worst case?”—unless it’s purely academic—has to come with a time frame. We cannot even begin to imagine what technology and society will be like thousands of years from now. In fact, do we even have knowledge that could enable us to help our descendants much past 2100? Similarly, should—or even could—our ancestors have done anything to prevent today’s problems? Michael Crichton explored this question in 2003:

“Let’s think back to people in 1900 in, say, New York. If they worried about people in 2000, what would they worry about? Probably: Where would people get enough horses? And what would they do about all the horseshit? Horse pollution was bad in 1900, think how much worse it would be a century later, with so many more people riding horses?”

The idea that it is meaningful to plan for the future beyond a few decades has gradually come to seem normal, but has there ever been any serious discussion of its validity? The closest thing we have to a rational empirical approach to it—looking at historical experience—hardly supports it.

If historical experience so far is any guide, even in 2100 technologies will exist that are currently inconceivable, at least in practical terms. 2100 is 80 years from now. If we go 80 years back, to 1940, technologies that have shaped today’s world were in the process of being invented. Nuclear weapons considered possible in theory, but no one knew how powerful they might be. The first programmable general-purpose electronic digital computer had not yet been built, and in the early days, computers were seen as calculating machines and nothing more.

That does not mean there is absolutely nothing we can know about the distant future. Astronomical and geological events are predictable across eons. And it might be a reasonable guess that the human population will peak within a century and then decline. But none of that has much practical application.

That’s why I say it’s fiction. Fiction can have value, but we need to distinguish it from reality. And I see the current tendency to extend the time frame as an attempt to maintain or escalate the sense of alarm about climate change when even the worst-case projections for this century seem relatively benign.