Hansen: Earth on Track for Catastrophic Warming

May 20, 2023

Jeff Berardelli tweeted out James Hansen’s latest email communication, with a summary of recent, as yet not peer reviewed research.
It’s sobering enough to discuss.

In the video above, in a lecture from 2010-ish time frame, Hansen lays out a masterful explanation of the last 66 million years of earth’s climate history. The sound is muted the first 20 seconds or so, but well worth your time if you have not seen, and good context for this new research.

James Hansen PhD:

Sorry to be slow in revising “Global Warming in the Pipeline.” It became apparent that looking at the whole Cenozoic era (past 66 million years) allowed the most persuasive case of where the planet is headed with today’s human-made climate forcings. With the help of Makiko Sato and Isabelle Sangha, I added a section on the Cenozoic, now perhaps the most informative part of the paper. For example, the present greenhouse gas forcing is 70% of the forcing that made Earth’s temperature in the Early Eocene Climatic Optimum at least +13°C relative to preindustrial temperature.

We are sending the paper today to the non-local co-authors and putting it on arXiv. It will likely take a couple of weeks for co-authors to review it, so there is the opportunity for others to make suggestions in the meantime, which we would welcome. I will ask the co-authors not to discuss the paper with the media until it is submitted, accepted, and is near publication.

The Cenozoic analysis is simple. The essential assumption is that there are 60 m of sea level in the Greenland and Antarctic ice sheets between today and an ice-free planet and an additional 120 m of sea level between today and the last glacial maximum. Sea level change is assumed to be linear in the oxygen isotope δ18O between today and either of those two states. Temperatures and sea level deduced from ocean core δ18O agree well with available independent data (Figs. 9 and S6).

The draft paper is available here. We will resume monthly communications on global temperature next month and deal with a backlog of other communications.

Below, how good have Hansen’s projections been in the past?


2 Responses to “Hansen: Earth on Track for Catastrophic Warming”

  1. rhymeswithgoalie Says:

    My first question if someone says “The climate has changed in the past” would be “How do you know that?”

    Could it be…science?

    We also know that Earth’s surface was once molten. We wouldn’t want to go back to those times, either.

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