1. A pandemic kills at least 2 million people. There are theories that the pathogen is bioengineered; they may even turn out to be true.
2. At least one of Amazon/Apple/Google/Microsoft/Facebook's market capitalization on 1/1/2030 is lower than its market capitalization on 1/1/2020.
3. There's a 60%+ drawdown at some point in the 2020s in US equities, exacerbated by baby boomers panic selling their retirement funds.
4. Mean global temperatures are at least 1K over the 1951-1980 baseline every year in the latter half of the decade.
5. US prime-age labor force participation trends downward -- the Keynesian post-work future is here, it's just not evenly distributed.
6. A non-Chromium-based browser has at least 25% market share.
7. Humans return to the Moon, but Mars is still at least a few years away.
8. Practical nuclear fusion is also still just a few years away.
9. There are still hundreds of millions of cases of malaria killing hundreds of thousands of people a year; rich Westerners still talk way more about the hundreds of Westerners a year killed in mass shootings.
And just to get some sports in:
10. LeBron James Jr. is not playing in the NBA in 2030.