evidence: Under ongoing global warming, further ice loss is to be expected for all of the four cryosphere components considered here; however, the corresponding time scales differ by several orders of magnitude. While substantial ice loss from Greenland or Antarctica might be triggered by anthropogenic climate change within the current century, these changes would manifest over several centuries to millennia15. Ice-free Arctic summers on the other side might already occur in the next decades1,7,9. Therefore, we also consider the regional warming caused solely by the loss of the Arctic summer sea ice (Fig. 1b). The additional warming in the Arctic region on a yearly average accounts for more than 1.5 °C regionally and for 0.19 °C globally. The meltdown of the Arctic sea ice and its regional warming effect is also simulated by CMIP-5 runs dependent on the future anthropogenic CO2 forcing scenarios, the RCP scenarios6,9. [...] Fig. 4: Additional warming due to meltdown of Arctic summer sea ice. [...] Notz, D. & Stroeve, J. Observed arctic sea-ice loss directly follows anthropogenic CO2 emission. Science354, 747–750 (2016).