Some may be wondering... can this happen today with the rapid retreat of glaciers, ice caps and ice sheets?

Not really, not for the majority of the globe. As an example, the Cordilleran ice sheet, at its maximum extent contained a sea-level equivalent comparable to that of the present-day Greenland Ice Sheet^1, ^2 That amount of mass pushing down the crust simply isn't there anymore to yield the degree of decompression melting required to produce that much melt (magma) and ultimately trigger a volcanic response.

What about Greenland and Antarctica?

As far as Greenland goes, it doesn't seem likely we'll see any activity there as there are no active volcanoes in Greenland, nor are there any known mapped, dormant volcanoes under the Greenland ice sheet that were active during the Pliocene period of geological history that began more than 5.3 million years ago (volcanoes are considered active if they’ve erupted within the past 50,000 years).

Antarctica, however, does have active volcanoes. I suspect that with the rapid deglaciation of the Antarctic Ice Sheet it may be possible to see an increase in volcanic activity regionally. Though due to its location (at the south pole), and the circumpolar winds and currents, any volcanic ash would also be quite limited globally and would likely remain at the poles rather than spreading out and having any major climatic effects.

Study: Volcanic trigger of ocean deoxygenation during Cordilleran ice sheet retreat

>Abstract

>North Pacific deoxygenation events during the last deglaciation were sustained over millennia by high export productivity, but the triggering mechanisms and their links to deglacial warming remain uncertain. Here we find that initial deoxygenation in the North Pacific immediately after the Cordilleran ice sheet (CIS) retreat was associated with increased volcanic ash in seafloor sediments. Timing of volcanic inputs relative to CIS retreat suggests that regional explosive volcanism was initiated by ice unloading. We posit that iron fertilization by volcanic ash during CIS retreat fuelled ocean productivity in this otherwise iron-limited region, and tipped the marine system towards sustained deoxygenation. We also identify older deoxygenation events linked to CIS retreat over the past approximately 50,000 years. Our findings suggest that the apparent coupling between the atmosphere, ocean, cryosphere and solid-Earth systems occurs on relatively short timescales and can act as an important driver for ocean biogeochemical change.

Remember that nothing has to be "beneficial" for it to remain, it simply needs not be selected against.

This study is in good agreement with previous studies that examined the likes of the "clathrate bomb hypothesis". For example, see the following findings from 2017: https://www.usgs.gov/news/national-news-release/gas-hydrate-breakdown-unlikely-cause-massive-greenhouse-gas-release

Study: Negligible atmospheric release of methane from decomposing hydrates in mid-latitude oceans

>Abstract

>Naturally occurring gas hydrates may contribute to a positive feedback for global warming because they sequester large amounts of the potent greenhouse gas methane in ice-like deposits that could be destabilized by increasing ocean/atmospheric temperatures. Most hydrates occur within marine sediments; gas liberated during the decomposition of seafloor hydrates or originating with other methane pools can feed methane emissions at cold seeps. Regardless of the origin of seep methane, all previous measurements of methane emitted from seeps have shown it to have a unique fossil radiocarbon signature, contrasting with other sources of marine methane. Here we present the concentration and natural radiocarbon content of methane dissolved in the water column from the seafloor to the sea surface at seep fields along the US Atlantic and Pacific margins. For shallower water columns, where the seafloor is not within the hydrate stability zone, we do document seep CH4 in some surface-water samples. However, measurements in deeper water columns along the US Atlantic margin reveal no evidence of seep CH4 reaching surface waters when the water-column depth is greater than 430 ± 90 m. Gas hydrates exist only at water depths greater than ~550 m in this region, suggesting that the source of methane escaping to the atmosphere is not from hydrate decomposition.

Study (open access): Tunnel valley formation beneath deglaciating mid-latitude ice sheets: Observations and modelling

>Highlights

>• Numerical experiments and geophysical data are used to investigate tunnel valley formation beneath deglaciating ice sheets.

>• New high-resolution 3D seismic data reveal abandoned channel systems, slumps, and subglacial landforms inside tunnel valleys.

>• Migrating channels fed by seasonal surface meltwater erode tunnel valleys within 100s to 1000s of years during deglaciation.

>• Modelled tunnel valleys form time-transgressively close to the retreating ice sheet margin.

>• Our results explain the formation of tunnel valleys in most previously glaciated regions.

>Abstract

>The geological record of landforms and sediments produced beneath deglaciating ice sheets offers insights into inaccessible glacial processes. Large subglacial valleys formed by meltwater erosion of sediments (tunnel valleys) are widespread in formerly glaciated regions such as the North Sea. Obtaining a better understanding of these features may help with the parameterisation of basal melt rates and the interplay between basal hydrology and ice dynamics in numerical models of past, present, and future ice-sheet configurations. However, the mechanisms and timescales over which tunnel valleys form remain poorly constrained. Here, we present a series of numerical modelling experiments, informed by new observations from high-resolution 3D seismic data (6.25 m bin size, ∼4 m vertical resolution), which test different hypotheses of tunnel valley formation and calculate subglacial water routing, seasonal water discharges, and the rates at which tunnel valleys are eroded beneath deglaciating ice sheets. Networks of smaller or abandoned channels, pervasive slump deposits, and subglacial landforms are imaged inside and at the base of larger tunnel valleys, indicating that these tunnel valleys were carved through the action of migrating smaller channels within tens of kilometres of the ice margin and were later widened by ice-contact erosion. Our model results imply that the drainage of extensive surface meltwater to the ice-sheet bed is the dominant mechanism responsible for tunnel valley formation; this process can drive rapid incision of networks of regularly spaced subglacial tunnel valleys beneath the fringes of retreating ice sheets within hundreds to thousands of years during deglaciation. Combined, our observations and modelling results identify how tunnel valleys form beneath deglaciating mid-latitude ice sheets and have implications for how the subglacial hydrological systems of contemporary ice sheets may respond to sustained climate warming.