The origin of life is the unsolved problem of how geochemistry became biochemistry. On the early Earth, I argue that chemically reducing atmospheres were inevitable consequences of big impacts and made molecules essential for the origin of life. On land, evaporative soda lakes (i.e., rich in sodium carbonate) are also likely because such lakes arise in closed basins in basaltic rocks as the aquatic chemistry evolves. Evaporative lakes can concentrate critical species needed for prebiotic synthesis, such phosphate, and promote polymerization during wet-dry cycles. My group examined a modern natural lake, Last Chance Lake, Canada, as a geochemical origin-of-life analog, revealing why it is the world’s most phosphate-rich lake.

David Catling is an Earth & Space Sciences professor at the University of Washington, Seattle. His research deals with how Earth’s environment and early life co-evolved on long timescales and the general habitability of planets. He is a 2023 American Geophysical Union Fellow for “creative insights into coupling between Earth’s biota and its atmosphere over timescales of billions of years”. After finishing a doctorate in atmospheric, oceanic and planetary physics at the University of Oxford in 1994, he worked at NASA Ames Research Center for 6 years. Then, in 2001, he moved to the University of Washington. In addition to scholarly papers, he has written Astrobiology: A Very Short Introduction for the layperson and Atmospheric Evolution on Inhabited and Lifeless Worlds for researchers.