The article "Observations: Oceanic Climate Change and Sea Level" provides a comprehensive overview of recent observations on oceanic climate change and sea level rise. Key findings include the warming of the oceans, with global ocean temperature increasing by 0.10°C from 1961 to 2003, and a significant increase in ocean heat content, equivalent to absorbing energy at a rate of 0.21 ± 0.04 W m⁻² globally. The warming is most pronounced in the upper 700 meters of the ocean, with a notable increase in the period 1993 to 2003, followed by some cooling after 2003. Salinity trends show a global freshening in subpolar latitudes and a salinification in tropical and subtropical regions, consistent with changes in precipitation and atmospheric water transport. Key oceanic water masses are changing, though there is no clear evidence for ocean circulation changes. The Southern Ocean mode waters and Upper Circumpolar Deep Waters have warmed significantly since the 1960s, while the Gulf Stream and Kuroshio mode waters have shown weaker warming patterns. Long-term cooling is observed in the North Atlantic subpolar gyre and the central North Pacific. Ocean biogeochemistry is also changing, with the total inorganic carbon content of the oceans increasing by 118 ± 19 GtC between the end of the pre-industrial period and 1994. This has led to a decrease in the depth at which calcium carbonate dissolves and a decrease in surface ocean pH by an average of 0.1 units since 1750. There is evidence for decreased oxygen concentrations in the thermocline, likely driven by reduced water renewal. Global mean sea level has been rising, with an average rate of 1.8 ± 0.5 mm yr⁻¹ from 1961 to 2003. The rate of sea level rise has increased between the mid-19th and mid-20th centuries, with significant regional variations. The rise in sea level is linked to changes in ocean circulation and is influenced by factors such as thermal expansion and melting of ice sheets. The article also discusses the variability in ocean heat content and salinity, highlighting the importance of these factors in understanding climate change. The patterns of observed changes in ocean heat content, salinity, sea level, and biogeochemical parameters are consistent with the observed ocean surface changes and the characteristics of large-scale ocean circulation. The article concludes that the ocean plays a crucial role in climate variability and change, and that understanding these changes is essential for predicting future climate scenarios.The article "Observations: Oceanic Climate Change and Sea Level" provides a comprehensive overview of recent observations on oceanic climate change and sea level rise. Key findings include the warming of the oceans, with global ocean temperature increasing by 0.10°C from 1961 to 2003, and a significant increase in ocean heat content, equivalent to absorbing energy at a rate of 0.21 ± 0.04 W m⁻² globally. The warming is most pronounced in the upper 700 meters of the ocean, with a notable increase in the period 1993 to 2003, followed by some cooling after 2003. Salinity trends show a global freshening in subpolar latitudes and a salinification in tropical and subtropical regions, consistent with changes in precipitation and atmospheric water transport. Key oceanic water masses are changing, though there is no clear evidence for ocean circulation changes. The Southern Ocean mode waters and Upper Circumpolar Deep Waters have warmed significantly since the 1960s, while the Gulf Stream and Kuroshio mode waters have shown weaker warming patterns. Long-term cooling is observed in the North Atlantic subpolar gyre and the central North Pacific. Ocean biogeochemistry is also changing, with the total inorganic carbon content of the oceans increasing by 118 ± 19 GtC between the end of the pre-industrial period and 1994. This has led to a decrease in the depth at which calcium carbonate dissolves and a decrease in surface ocean pH by an average of 0.1 units since 1750. There is evidence for decreased oxygen concentrations in the thermocline, likely driven by reduced water renewal. Global mean sea level has been rising, with an average rate of 1.8 ± 0.5 mm yr⁻¹ from 1961 to 2003. The rate of sea level rise has increased between the mid-19th and mid-20th centuries, with significant regional variations. The rise in sea level is linked to changes in ocean circulation and is influenced by factors such as thermal expansion and melting of ice sheets. The article also discusses the variability in ocean heat content and salinity, highlighting the importance of these factors in understanding climate change. The patterns of observed changes in ocean heat content, salinity, sea level, and biogeochemical parameters are consistent with the observed ocean surface changes and the characteristics of large-scale ocean circulation. The article concludes that the ocean plays a crucial role in climate variability and change, and that understanding these changes is essential for predicting future climate scenarios.