ALL INPredictions
Last updated Nov 29, 2025
Prediction
Chamath
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Chamath @ 00:18:32Wrong
climate
If (as expected by the speakers in this discussion) the U.S. Bureau of Reclamation declares a Tier 1 shortage on the Colorado River based on its end-of-2021 Lake Mead assessment, then in calendar year 2022 Arizona’s water allocation from the Colorado River will be cut by roughly 600,000 acre-feet (about 15% of the state’s demand), leading to noticeable water-use restrictions in Arizona.
there's a really important assessment that's going to happen in Lake Mead, um, at the end of this year. And the reason why it's critical is that if the US Bureau of Reclamation measures Lake Mead under, um, a certain threshold, uh, they can declare a tier one shortage. And what that means, just practically speaking, cutting through all the, you know, jargon is that initially, the state of Arizona will be denied around 600,000 acre feet of water next year. What does that mean? That's about 15% of the demand for that state. And so you're going to start to deal with these sort of like rolling...View on YouTube
Explanation

The conditional part of the prediction did occur, but the magnitude and especially the consequences were substantially misstated.

  1. Tier 1 shortage and size of Arizona’s cut
    • In August 2021, the U.S. Bureau of Reclamation’s August 2021 24‑Month Study formally declared, for the first time, a Colorado River shortage for 2022 at Lake Mead, triggering a Tier 1 shortage for the Lower Basin, including Arizona. (en.wikipedia.org)
    • Under that Tier 1 shortage, Arizona’s Colorado River allocation in 2022 was cut by 512,000 acre‑feet, about 18% of its 2.8 million acre‑feet allocation and roughly 8% of Arizona’s total water use, not “about 600,000 acre‑feet” and not ~15% of statewide demand. (kunc.org)
    • So, while he correctly anticipated that a Tier 1 shortage would be declared and that Arizona would face a large cut, his numerical claims (“around 600,000 acre‑feet” and “about 15% of the demand for that state”) were meaningfully off.

  2. Who actually got cut and by how much
    • Central Arizona Project (CAP) and state sources describe the 2022 Tier 1 cut as a 512,000 acre‑foot reduction, equal to about 30% of CAP’s normal supply, about 18% of Arizona’s Colorado River supply, and just under 8% of total statewide water use—almost all borne by CAP users. (cap-az.com)
    • Detailed impact analyses emphasize that the cuts fell primarily on agricultural users in central Arizona (especially Pinal County), with large areas of farmland fallowed and heavy reliance on groundwater. (farmprogress.com)

  3. Did this cause noticeable water‑use restrictions for Arizonans in 2022?
    • The Arizona Municipal Water Users Association explained that under the 2022 Tier 1 shortage, municipalities and tribes (which hold higher‑priority CAP rights) would not face water reductions, and that “a shortage on the Colorado River does not mean there will be a shortage at your tap” with no immediate impact on cities’ ability to serve customers. (amwua.org)
    • Major cities (Phoenix, Glendale, Mesa) did activate Stage 1 drought/water alerts in mid‑2022, but these focused on education and voluntary conservation, explicitly stating that there were no mandatory water restrictions for residents or businesses at that stage. (phoenix.gov)
    • In other words, while farmers experienced severe cuts and land fallowing, most Arizona residents did not face the kind of “rolling” or compulsory water‑use restrictions implied in the prediction during calendar year 2022.

Because the actual cut was notably smaller than he stated, his 15%-of-demand figure was wrong, and the Tier 1 shortage in 2022 did not lead to broad, noticeable water‑use restrictions on the public (only voluntary measures and agricultural impacts), the overall prediction is best classified as wrong, despite being directionally correct about there being a Tier 1 shortage and significant cuts to Arizona’s Colorado River allocation.