stylistic:style_transfer, structural:reformatting
Near-term

In 2021, the IPCC Sixth Assessment Report estimated that under SSP5-8.5, the scenario associated with the highest global warming, Greenland ice sheet melt would add around 13 cm (5 in) to the global sea levels (with a likely (17%–83%) range of 9–18 cm (3 + 1 ⁄ 2 –7 in) and a very likely range (5–95% confidence level) of 5–23 cm (2–9 in)), while the "moderate" SSP2-4.5 scenario adds 8 cm (3 in) with a likely and very likely range of 4–13 cm (1 + 1 ⁄ 2 –5 in) and 1–18 cm (1 ⁄ 2 –7 in), respectively. The optimistic scenario which assumes that the Paris Agreement goals are largely fulfilled, SSP1-2.6, adds around 6 cm (2 + 1 ⁄ 2 in) and no more than 15 cm (6 in), with a small chance of the ice sheet gaining mass and thus reducing the sea levels by around 2 cm (1 in).

Some scientists, led by James Hansen, have claimed that the ice sheets can disintegrate substantially faster than estimated by the ice sheet models, but even their projections also have much of Greenland, whose total size amounts to 7.4 m (24 ft) of sea level rise, survive the 21st century. A 2016 paper from Hansen claimed that Greenland ice loss could add around 33 cm (13 in) by 2060, in addition to double that figure from the Antarctic ice sheet, if the CO concentration exceeded 600 parts per million, which was immediately controversial amongst the scientific community, while 2019 research from different scientists claimed a maximum of 33 cm (13 in) by 2100 under the worst-case climate change scenario.

As with the present losses, not all parts of the ice sheet would contribute to them equally. For instance, it is estimated that on its own, the Northeast Greenland ice stream would contribute 1.3–1.5 cm by 2100 under RCP 4.5 and RCP 8.5, respectively. On the other hand, the three largest glaciers - Jakobshavn, Helheim, and Kangerlussuaq - are all located in the southern half of the ice sheet, and just the three of them are expected to add 9.1–14.9 mm under RCP 8.5. Similarly, 2013 estimates suggested that by 2200, they and another large glacier would add29 to 49 millimetres by 2200 under RCP 8.5, or 19 to 30 millimetres under RCP 4.5. Altogether, the single largest contribution to 21st century ice loss in Greenland is expected to be from the northwest and central west streams (the latter including Jakobshavn), and glacier retreat will be responsible for at least half of the total ice loss, as opposed to earlier studies which suggested that surface melting would become dominant later this century. If Greenland were to lose all of its coastal glaciers, though, then whether or not it will continue to shrink will be entirely determined by whether its surface melting in the summer consistently outweighs ice accumulation during winter. Under the highest-emission scenario, this could happen around 2055, well before the coastal glaciers are lost.

Sea level rise from Greenland does not affect every coast equally. The south of the ice sheet is much more vulnerable than the other parts, and the quantities of ice involved mean that there is an impact on the deformation of Earth's crust and on Earth's rotation. While this effect is subtle, it already causes East Coast of the United States to experience faster sea level rise than the global average. At the same time, Greenland itself would experience isostatic rebound as its ice sheet shrinks and its ground pressure becomes lighter. Similarly, a reduced mass of ice would exert a lower gravitational pull on the coastal waters relative to the other land masses. These two processes would cause sea level around Greenland's own coasts to fall, even as it rises elsewhere. The opposite of this phenomenon happened when the ice sheet gained mass during the Little Ice Age: increased weight attracted more water and flooded certain Viking settlements, likely playing a large role in the Viking abandonment soon afterwards.