Editing IPCC:AR6/SROCC/Chapter-1 (section)

=== 1.2.2 Interactions Between the Ocean and Cryosphere ===

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The ocean and cryosphere are interconnected in a multitude of ways (Box 1.1, Figure 1). Evaporation from the ocean provides snowfall that builds and sustains the ice sheets and glaciers that store large amounts of frozen water on land (Section 4.2.1). The vast ice sheets in Antarctica and Greenland currently hold about 66 m of potential global sea level rise (Fretwell et al., 2013 <sup>[[#fn:r50|50]]</sup> ), although the loss of a large fraction of this potential would require millennia of ice sheet retreat. Ocean temperature and sea level affect ice sheet, glacier and ice shelf stability in places where the base of ice bodies are in direct contact with ocean water (Section 3.3.1). The nonlinear response of ice-melt to ocean temperature changes means that even slight increases in ocean temperature have the potential to rapidly melt and destabilise large sections of an ice sheet or ice shelf ( Section 3.3.1.5).

The formation of sea ice leads to the production of dense ocean water that contributes to the deep ocean circulation (Section 3.3.3.2 ). Paleoclimate evidence and modelling indicates that releases of large amounts of glacier and ice sheet melt water into the surface ocean can disrupt deep overturning circulation of the ocean, causing global climate impacts (Knutti et al., 2004 <sup>[[#fn:r51|51]]</sup> ; Golledge et al., 2019 <sup>[[#fn:r52|52]]</sup> ). Ice sheet melt water in the Antarctic may cause changes in surface ocean salinity, stratification and circulation, that feedback to generate further ocean-driven melting of marine-based ice sheets (Golledge et al., 2019 <sup>[[#fn:r53|53]]</sup> ) and promote sea ice formation (Purich et al., 2018 <sup>[[#fn:r54|54]]</sup> ). The cryosphere and ocean further link through the movement of biogeochemical nutrients. For example, iron accumulated in sea ice during winter is released to the ocean during the spring and summer melt, helping to fuel ocean productivity in the seasonal sea ice zone (Tagliabue et al., 2017 <sup>[[#fn:r55|55]]</sup> ). Nutrient rich sediments delivered by glaciers further connect cryosphere processes to ocean productivity (Arrigo et al., 2017 <sup>[[#fn:r56|56]]</sup> ).

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