Climate Trivia: Ocean Salinity
Melting ice and intensification of Earth’s water cycle appear to be impacting how salty ocean waters are. How salty the water is affects sea levels as well as Earth’s thermohaline circulation – the ocean currents driven by differences in temperature and salinity. Both changes in sea levels and the thermohaline circulation can have consequences for Earth’s climate.
Trivia Question: Which of the following best characterizes recent trends in ocean surface salinity?
a) Fresher tropics, saltier high-latitudes
b) Fresher Atlantic and Indian Oceans, and a saltier Pacific
c) A fresher Pacific, a saltier Atlantic, and no change in the Indian Ocean
d) Ocean waters are freshening near the poles and getting saltier near the equator
The correct answer is d. Increased input of fresh water into the higher latitude parts of the oceans as glaciers melt and precipitation increases is being largely counteracted by increased evaporation (and thus saltier waters) in the tropics and especially the subtropics. The areas immediately around the Equator are also freshening. The Atlantic Ocean is experiencing a freshening of the waters between 45 and 70 degrees North, as well as in waters near Antarctica. Most of the Indian Ocean, which lies largely in the tropics, is becoming saltier. The Pacific also follows the general rule, with an especially strong freshening around the Equator, and the tropical and subtropical waters are becoming more saline. The far South Pacific and the Indian Ocean around Antarctica are also freshening.
Seasons: Winter, Spring, Summer, Fall
Source: Boyer, TP et al. “Linear Trends in Salinity for the World Ocean, 1955-1998.” Geophysical Research Letters 32 (2005): L01604 and Durack, P and Wijffels, S. “Fifty-year Trends in Global Ocean Salinities and Their Relationship to Broad-Scale Warming.” Journal of Climate Preprint (2010): Accessed Online:
