They show that saltier oceans result in warmer climates, partly because the salt depresses the freezing point of seawater and inhibits sea-ice formation, but mostly because the greater density of salty water alters ocean circulation patterns and aids heat transport to the poles. Under their Archean scenario they show that present-day levels of salinity produce a severely glaciated world with only a narrow strip of open water at the equator. But pushing salinity up to 40% greater than today revealed a warmer Archean world, with average surface temperatures of more than 20C, and ice only appearing seasonally at the poles. Their findings are reported in Geophysical Research Letters.
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