The global temperature difference between the ocean’s surface and a depth of 200 m increased on average by 0.25°C from 1971 to 2010 (Levitus et al., Observations since 1971 indicate that thermal expansion and glacier melt (excluding Antarctic glaciers peripheral to the ice sheet) explain 75% of the observed rise. The contribution of the Greenland and Antarctic ice sheets has increased since the early 1990s, partly from increased outflow induced by warming of the immediately adjacent ocean (Church et al., Ocean physics and chemistry would be quite different in these two emissions scenarios, with the differences becoming ever more pronounced as we move through the 21st century.