Their estimate of SLR is the opposite of a conservative one, their estimate is at the upper range of previous estimates. Edwards et al. (2021) provided us with the most up-do-date results from the Ice Sheet Model Intercomparison Project (ISMIP6) for Coupled Model Intercomparison Project Phase 6 (CMIP6).

From Park et al. (2023), this paper,

>For the SSP1-1.9, SSP2-4.5 and SSP5-8.5 scenarios the GrIS contributes about 12 ± 1, 18 ± 0.9 and 23 ± 1.6 cm and the AIS adds 3 ± 0.8, 7 ± 1.4, and 15 ± 1.5 cm to SL by the year 2100 relative to pre-industrial levels (Fig. 2c, d). 2100 CE (2150 CE) LOVECLIP simulates for the respective scenarios a total ice-sheet contribution to SL of 15 ± 0.9, 24 ± 1.3, 39 ± 2 (19 ± 1.4, 48 ± 1.4, 136 ± 6.2) cm (Fig. 2b).

Compare this to Edwards, from Table 1, which reports median and 5th-95th percentiles, under SSP5-8.5 by 2100, the GrIS contributes 10cm [2,20], the AIS contributes 4cm [-4,14].

Note however, that Park is reporting SLR from pre-industrial, while Edwards is reporting post-2015 SLR, which means you would need to subtract the pre-2015 contributions for a complete comparison. This would have the effect of subtracting less than ~1cm from GrIS, and ~2cm from AIS in Park.

In fact, the AIS contribution found in Park is closer to the median in Edwards' worst-case "Risk-averse projection" which combine assumptions that lead to the highest AIS contribution.

In short, this paper's results for 21st century SLR are from from "conservative" in the sense that they actually fall within the upper range of probability of previous research. They themselves note,

>The GrIS and AIS contributions lie within the range of estimates obtained from uncoupled scenario-forced models for Greenland and Antarctica

Edit: A previous version of this comment was in complete error, mea culpa!