The Council on Foreign Relations (CFR) posts an article at the end of every year with their opinions about what the 10 most significant world events were.

Examples of what they named the year's most significant event in the last 3 years:
2022 - Russia Invades Ukraine
2021 - Countries Fail the Climate Change Challenge—Again
2020 - The COVID-19 Pandemic

Link for the 2022 article: https://www.cfr.org/blog/ten-most-significant-world-events-2022

This should be an exciting market to track people's best guesses about the most important events of 2023 in real-time. You can suggest your guesses on what CFR will name as the year's most significant event.

EDIT: this is outdated: Note that if there are two similar proposed answers, I will resolve to the one that more closely matches CFR's language. E.g. for 2022, two suggested answers could have been "War between Ukraine and Russia" and "Russia attacks Ukraine." In that case, I would have resolved to the latter option because it is closer to CFR's framing of "Russia invades Ukraine."

EDIT: Updated resolution criteria: Please look at the suggested answers so far and only propose answers that haven't been suggested yet. For those entries where we already have two similar ones, I will multi-resolve if those are chosen by CFR. This is currently the case for these two pairs: "China invades Taiwan", "Chinese invasion of Taiwan" and "Catastrophic climate change", "Extreme weather events (floods, hurricanes, droughts) caused by climate change shock the world". From now on, if someone suggests an answer that I deem too similar to one of the existing answers, I will NOT multi-resolve, but only resolve to the answer that was suggested first.

If there is a lot of ambiguity after the CFR article comes out, I will hear arguments about what to resolve in the comments. If nobody suggests an answer close enough to CFR's number one most significant event, I will resolve N/A, but I think that is unlikely.

You can start making guesses about what you anticipate as the year's most significant event. Still, I expect that the winning suggestion will be put forward during the year once events unfold.

Jan 6, 11:30am: What will be the most significant world event in 2023, according to the Council on Foreign Relations? → What will be the most significant world event in 2023, according to the Council on Foreign Relations?