This is a linkpost for "This Can't Go On", part of the Most Important Century blog post series by Holden Karnofsky. In this post, Karnofsky argues that we should not expect the current trend of steady economic growth at around 2-3% per year to continue indefinitely, for two reasons. First, economic growth has been faster in the last two centuries than it has been in the rest of human history. Second, if the current trend continues, economic activity will eventually reach some as-yet-unknown physical limit within the next 10,000 years.

Instead, we should expect at least three possibilities:

• Stagnation: Economic growth will eventually slow down and stop as the economy reaches its maximum size.
• Explosion: Economic growth will accelerate further, perhaps due to a general-purpose technology like artificial general intelligence that accelerates innovation.
• Collapse: A global catastrophe permanently ruins the world economy and we never reach today's level of growth again.

For copyright reasons, I won't reproduce the entire post here, but here's an excerpt that I've found especially thought-provoking:

A good starting point would be this analysis from Overcoming Bias, which I'll give my own version of here:

• Let's say the world economy is currently getting 2% bigger each year. This implies that the economy would be doubling in size about every 35 years.
• If this holds up, then 8200 years from now, the economy would be about 3*10⁷⁰ times its current size.
• There are likely fewer than 10⁷⁰ atoms in our galaxy, which we would not be able to travel beyond within the 8200-year time frame.
• So if the economy were 3*10⁷⁰ times as big as today's, and could only make use of 10⁷⁰ (or fewer) atoms, we'd need to be sustaining multiple economies as big as today's entire world economy per atom.

...

Is it imaginable that we could develop the technology to support multiple equivalents of today's entire civilization, per atom available? Sure - but this would require a radical degree of transformation of our lives and societies, far beyond how much change we've seen over the course of human history to date....

It seems much more likely that we will "run out" of new scientific insights, technological innovations, and resources, and the regime of "getting richer by a few percent a year" will come to an end. After all, this regime is only a couple hundred years old.