Earth's long-term climate has been profoundly influenced by the episodic assembly and breakup of supercontinents at intervals of ca. 500 m.y. This reflects the cycle's impact on global sea level and atmospheric CO₂ (and other greenhouse gases), the levels of which have fluctuated in response to variations in input from volcanism and removal (as carbonate) by the chemical weathering of silicate minerals. Supercontinent amalgamation tends to coincide with climatic cooling due to drawdown of atmospheric CO₂ through enhanced weathering of the orogens of supercontinent assembly and a thermally uplifted supercontinent. Conversely, breakup tends to coincide with increased atmospheric CO₂ and global warming as the dispersing continental fragments cool and subside, and weathering decreases as sea level rises. Supercontinents may also influence global climate through their causal connection to mantle plumes and large igneous provinces (LIPs) linked to their breakup. LIPs may amplify the warming trend of breakup by releasing greenhouse gases or may cause cooling and glaciation through sulfate aerosol release and drawdown of CO₂ through the chemical weathering of LIP basalts. Hence, Earth's long-term climatic trends likely reflect the cycle's influence on sea level, as evidenced by Pangea, whereas its influence on LIP volcanism may have orchestrated between Earth's various climatic states. 35 , 70 , 71 , 78 , 124 The cycle is likely driven by some combination of continental insulation, mantle plume dynamics, and slab rollback. The mechanism first proposed was that of continental insulation, 61 , 110 , 125 whereby the thermal insulating effect of continental lithosphere on mantle heat flow is considered to trap mantle heat beneath supercontinents resulting in their thermal uplift and breakup. 62 , 63 , 64 , 66 In fact, the close correspondence between the changes in global sea level predicted by the cycle for the Phanerozoic, 61 which amounted to several hundred meters, and the contemporary depositional record of sea level change over the same interval 146 was a key argument used in support of the original hypothesis (Figure 5 ). Supercontinents tend to correspond to intervals of very low global sea level 112 , 147 as a result of their epeirogenic uplift, either because continental insulation traps mantle heat beneath them, and/or because descent of the subduction girdle to the core–mantle boundary fosters mantle upwelling beneath them. Both of these processes would be amplified if true polar wander brings the supercontinent to the equator as a consequence of centrifugal forces acting on the positive dynamic topography (excess mass) created by its thermal uplift, 50 , 54 , 132 since the reaction rates of chemical weathering, and hence the rate of drawdown of atmospheric CO 2 , are strongly dependent on temperature and precipitation. 76 , 156 As a likely result of these processes, the amalgamation of both Pangea and Pannotia was accompanied by cold, “icehouse” climates (Figure 7 ) and widespread continental glaciation—respectively, the c. 335–260 Ma Gondwanan 115 , 157 , 158 and the c. 640–635 Ma Marinoan 159 and c. 580/565 Ma Gaskiers/post‐Gaskiers. 160 , 161 , 162 , 163 Conversely, continental glaciation accompanied the breakup of Rodinia (c. 717–663 Ma Sturtian 164 , 165 , 166 ), Kenorland/Lauroscandia (c. 2.44–2.3 Ga Huronian [Gowganda] 167 , 168 , 169 ), and perhaps even the earliest proposed supercraton Ur (c. 2.9 Ga Pongola 170 , 171 , 172 ). This could reflect the abrupt erosional release of dissolved Ca and Mg to the oceans following the onset of rifting, 145 , 173 the combination of uplift and subsidence in rift settings having been long thought to provide ideal conditions for both the initiation of glaciation and the preservation of the resulting glacigenic sediments. 174 , 175 The role of the supercontinent cycle in continental glaciation, however, is a complex one, and while supercontinents may foster ice ages, they do not mandate them as evidenced by the apparent absence of any glaciation associated with Nuna/Columbia and its unrelated presence during the Hirnantian (c. 445 Ma) 176 , 177 and the Pleistocene to present day. FIGURE 7 Distribution of warm (greenhouse) and cool (icehouse) global climatic conditions for the past 1 Ga 124 compared with times of supercontinent assembly and breakup for Rodinia, Pannotia, and Pangea. The Huronian glaciations accompanying Kenorland/Lauroscandia also coincide with the Great Oxidation Event (c. 54 FIGURE 8 Time scale for estimated changes in global mean surface temperature, based on energy‐balance calculations, and ice extent through one complete snowball event. 192 The global palaeogeography is for 750 Ma, some 30 m.y. before the Sturtian glaciation. Abbreviations: Am, Amazonia; Au, Australia; Ba, Baltica; Co, Congo; In, India; K, Kalahari; M, Mawson; Si, Siberia; Ta, Tarim; WA, West Africa; Y, South China Once initiated, the icehouse conditions of a Snowball Earth are thought to prevail until volcanically sourced atmospheric CO 2 , deprived by ice cover of a continental weathering (and photosynthetic) sink, rises dramatically to c. 350 present atmospheric levels. It has been argued, for example, that the equatorial continental paleogeography of the Cryogenian, which would have favored cool global climates as a result of climate‐enhanced chemical weathering and organic carbon burial, 233 may have been driven into runaway global glaciation of the Sturtian Snowball Earth by the weathering of extensive LIP continental flood basalts erupted throughout the break‐up of Rodinia, such as those associated with the Gunbarrel (c. 780 Ma), Mundine Well (c. 755 Ma), and Franklin (c. 723 Ma) provinces. 145 , 234 , 235 Donnadieu et al . 145 further suggest that this may also have been the case for the Marinoan Snowball Earth.