[Rockhounds] The Effect of Ocean Salinity on Climate and Its Implications for Earth's Habitability

[Kreigh Tomaszewski]

The influence of atmospheric composition on the climates of present-day and
early Earth has been studied extensively, but the role of ocean composition
has received less attention. We use the ROCKE-3D ocean-atmosphere general
circulation model to investigate the response of Earth's present-day and
Archean climate system to low versus high ocean salinity. We find that
saltier oceans yield warmer climates in large part due to changes in ocean
dynamics. Increasing ocean salinity from 20 to 50 g/kg results in a 71%
reduction in sea ice cover in our present-day Earth scenario. This same
salinity change also halves the *p*CO2 threshold at which Snowball
glaciation occurs in our Archean scenarios. In combination with higher
levels of greenhouse gases such as CO2 and CH4, a saltier ocean may allow
for a warm Archean Earth with only seasonal ice at the poles despite
receiving ∼20% less energy from the Sun.

https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2021GL095748