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.
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