Do we have the technology to ease our melting ice sheets?

This past year, news outlets have been reporting that initial predictions for polar ice melt were overly optimistic: ice sheets are melting much faster than models for the 2021 Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report suggested. Irrespective of whether we achieve a low greenhouse gas (GHG) emission scenario, or continue within intermediate or high emission scenarios, we’re looking at an “ice-free” Arctic summer as early as the next decade (down from the initially estimated 2050s).

There’s a lot in that summary, though, which can easily create confusion. This is why better science communication around climate change is of critical importance, and why Kim Stanley Robinson’s The Ministry for the Future, which speculates about climate change mitigation, is the topic of this second series of Humanist Book Club. Today, we’re looking at the problem of glacial collapse from meltwater, but it certainly doesn’t hurt to first get a lock on the overall problem at our poles.

The pressing sea ice concern

For one, “ice-free” doesn’t mean zero ice. It’s a situation in which less than one million square kilometers (or around 386,000 square miles) is covered in sea ice, and in this case represents a highly plausible event during the lowest point of the Arctic’s annual cycle (in September) within a few years.

Ice levels fluctuate throughout the year, but the part that remains at the end of the Arctic summer is considerably thicker than its seasonal ice, and operates as a steady barrier for the transfer of heat and moisture between the atmosphere and ocean.

Whereas the ocean’s surface is dark and absorbs heat more readily, sea ice reflects sunlight. When this thickest part of our world’s ice barrier is eroded, we see an acceleration in further ice melt and glacier loss. This causes sea levels to rise and changes atmospheric conditions, giving way to new temperature and storm systems, and significantly impacting marine biology.

Some discussions of global warming treat rising water temperatures and ice melt (either on the surface of ice sheets or from glacial collapse) as separate phenomena. But the two feed into one another, which is why scientists and journalists are throwing around “ice-free” in the first place. Despite being an imperfect and easily misleading term for lay readers, this agreed-upon threshold draws attention to a consequential link between two critical climate change factors.

There are ice-free summers (the phenomenon under discussion) and ice-free winters, when the quantity of polar ice would be at this low point all year round (another problem, for another decade). In a non-global warming scenario, an ice-free summer isn’t necessarily an issue; there’s a cyclical stability that can reassert itself when the world isn’t warming at an accelerated rate. However, as the IPCC’s 2021 report noted, we’re undergoing a much more catastrophic transformation.

Ice sheets retreat more quickly than they grow because of processes that, once triggered, drive self-reinforcing ice loss. For ice sheets that are mostly resting on bedrock above sea level – like the Greenland Ice Sheet – the main self-reinforcing loop that affects them is the ‘elevation–mass balance feedback’. In this situation, the altitude of the ice-sheet surface decreases as it melts, exposing the sheet to warmer air. The lowered surface then melts even more, lowering it faster still, until eventually the whole ice sheet disappears. In places where the ice sheet rests instead on bedrock that is below sea level, and which also deepens inland, including many parts of the Antarctic Ice Sheet, an important process called ‘marine ice sheet instability’ is thought to drive rapid retreat. This happens when the part of the ice sheet that is surrounded by sea water melts. That leads to additional thinning, which in turn accelerates the motion of the glaciers that feed into these areas. As the ice sheet flows more quickly into the ocean, more melting takes place, leading to more thinning and even faster flow that brings ever-more glacier ice into the ocean, ultimately driving rapid deglaciation of whole ice-sheet drainage basins.

These (and other) self-reinforcing processes explain why relatively small increases in temperature in the past led to very substantial sea level rise over centuries to millennia, compared to the many tens of thousands of years it takes to grow the ice sheets that lowered the sea level in the first place. These insights from the past imply that, if human-induced changes to the Greenland and Antarctic ice sheets continue for the rest of this century, it will take thousands of years to reverse that melting, even if global air temperatures decrease within this or the next century. In this sense, these changes are therefore irreversible, since the ice sheets would take much longer to regrow than the decades or centuries for which modern society is able to plan.

“Chapter 9: Ocean, Cryosphere, and Sea Level Change”, IPCC Sixth Assessment 2021 Report (from Working Group I)

So forget about “ice-free”, except as a scientific shorthand for a key threshold.

The real problem is the whole cascade failure of our polar systems, and our failure to take more immediate and comprehensive action to bring it to a halt.

Challenges for the climate model

The other problem with most news summaries of this polar ice crisis is how they treat inevitable updates to our predictive modeling. The original IPCC report described key findings in terms of likelihood and confidence levels, based on simulations developed through Coupled Model Intercomparison Project Phase 6 (CMIP6) models. This system of “ensemble” modeling developed five scenarios for the 21st century, and produced around 30 models for each of the higher-temperature outcomes, and around 10 models for each of the lower-temperature outcomes, to seek average predicted impacts at different temperature thresholds. This work allowed the IPCC working group to conclude that

The Arctic is likely to be practically sea ice-free in September31 at least once before 2050 under the five illustrative scenarios considered in this report, with more frequent occurrences for higher warming levels. There is low confidence in the projected decrease of Antarctic sea ice.

“Summary for Policy Makers”, IPCC Sixth Assessment Report, Working Group I, 2021

The above italics can be found in the original, because the authors follow writing standards that emphasize limits to current knowledge. (A good way of combating misinformation.) A working model, after all, is only as good as its corroborating data, and the scientific community always expects refinements to its work.

Unsurprisingly then, a few scientists published work this year that countered the IPCC modeling. In March, for instance, American Meteorological Society gave us “The Deep Arctic Ocean and Fram Strait in CMIP6 Models”. Here, Céline Heuzé et al. reported that some of the baselines in the IPCC report were wanting:

Compared to observational climatologies and hydrographic profiles, the modeled Atlantic layer core is on average too cold by −0.4°C and too deep by 400 m in the Nansen Basin. The Atlantic layer is too thick, extending to the seafloor in some models. Deep and bottom waters are in contrast too warm by 1.1° and 1.2°C. Furthermore, the modeled properties hardly change throughout the Arctic.

… These models are very biased: too cold where they should be warm, too warm where they should be cold, not stratified enough, not in contact with the surface as they should, moving the wrong way around the Arctic, etc. Some problems are induced by biases in regions outside of the Arctic and/or from the sea ice models.

The key here isn’t just that these errors create a flawed baseline. The errors in contact points and water flows also impact the model’s ability to extrapolate to future data points as external factors intersect with the geography and hydrology under review. In interview, Heuzé shared a bleak view of the Arctic warming faster than these models report. In the paper itself, the team focused constructively on outlining the kind of metadata needed to make better predictions.

(This is why science must always be treated as a process: the IPCC released its findings, and work like this paper invite further refinements to a daunting project.)

A more recent round of critiques about the IPCC’s 2021 model then came from Yeon-Hee Kim et al.’s June publication in Nature Communications, “Observationally-constrained projections of an ice-free Arctic even under a low emission scenario”. There, the authors noticed that CMIP6 models drew from satellite data that measured “sea ice extent”, a concept that counts the total area of all grid squares with at least 15% sea ice in them. (Map gerrymandering? Sort of, but also often a necessary concession to the limits of satellite equipment.)

When “observationally constrained” simulations were run, drawing from data that showed higher rates of ice melt year-round and better tracked the role of GHG emissions in rising temperatures, the team found that all emissions scenarios would reach the ice-free threshold in the 2030s. This in turn meant that initial calculations had underestimated the rate of warming at the poles: now understood to be about four times the rate of the rest of the world over a 40-year period.

All of which raises a really important question about how to combat a problem, the magnitude of which is so difficult to assess. With the science still scrambling to catch up with the actual rate of planetary change, why wouldn’t we embrace informed speculation to help us try to cut off this escalating crisis at the pass?

Robinson’s The Ministry for the Future was published before the 2021 IPCC report, and just a little after the publication of the CMIP6 model projections, in September 2020. Even then, based on previous assessments, the scientific community was wondering about options to lessen ice melt. The problem then was Herculean, but the time scale for action was slightly more in their favor. Now, the problem remains Herculean and the odds are even more against us.

Does the solution that Robinson’s near-future book proposes, of drilling to lessen ice-melt acceleration, still work for us today? That’s the question we’re asking this week for Humanist Book Club. (And if not, is there any other hope for the ice?)

The pipe dream of Arctic drilling

Robinson’s depiction of a possible solution to polar ice melt and glacier loss takes place in stages: the proposal, the initial execution (and challenges therein), and the eventual success of the project.

Before we dive in, though, it’s important to highlight that none of the solutions in this text are meant to be read in isolation. When Robinson explores the possibility of drilling into the ice to pump out meltwater, he does not pretend that this solution could ever work on its own. This is meant as a stalling tactic, employed while the rest of the world works on reducing emissions at point of origin and reducing greenhouse gases in the atmosphere. Another such stalling tactic involves the use of dyes sprayed relentlessly over the oceans to improve the water’s reflectivity.

Drilling to pump up meltwater also requires staggering levels of international collaboration, which we also saw when wrestling with the possibility of a “carbon coin” and quantitative easing to incentivize sequestration. So it’s both an “easy” fix, and also one that would remain daunting and intricate in execution.

That said, here’s the problem and solution as it’s first pitched:

“Reality of the problem is that glaciers are sliding into the sea ten times faster than before. … [T]he reason for that is there’s more meltwater created on the ice surface every summer, because of global warming. That water runs down moulins until it reaches the undersides of the glaciers, and there it has nowhere else to go. So it lifts up the ice a bit. It lubricates the ice flow over the rock beds. The ice used to be in contact with the rock bed, at least in some places, and usually in most places. The ice is so heavy it used to crush out everything under it. It bottomed out. … Stuck.”

… “And so?” …

“You pump that water out from under the glaciers. Melt drillholes like we already do there when we check out subglacial lakes, or to get through the ice shelves. … Pump up the water from under the glaciers, and actually, the weight of the ice on it will cause that water to come up a well hole ninety percent of the way, just from pressure of all that weight. Then you pump it up the rest of the way, pipe it away from the glacier onto some stable ice nearby. … My modeling suggests that if you pump out about a third to a half of the water underneath the glaciers, you get them to slow down enough to reduce their shear heat also, and that water doesn’t appear in the first place. The glaciers cool down, bottom out, refreeze to the rock, go back to their old speed. So you only need to pump out something like thirty cubic kilometers, from under the biggest glaciers in Antarctica and Greenland. … Say the hundred biggest. It’s not so bad.”

Kim Stanley Robinson, The Ministry for the Future, 2020

This is ambitious modeling, but only because of the scale of the commitment, rather than the technology necessary for success. Today, we use drilling technology to save ancient ice samples from further ice melt, and to better understand the phenomenon of Arctic amplification. With extensive coordination and dedicated project management, it could be attempted on a mass scale.

The book goes on to illustrate, though, that there would be challenges in the follow-through. When a team is sent out to test the basic principle, it recognizes the variable hydrology that might change the height at which the water rises of its own accord, considers the possible negative impact on any silt at the bottom of the glaciers, and… ultimately pulls off a few days of steady water draw before a mysterious halt to proceedings. Did they reach the end of the meltwater, or did the shifting glacier cut off the well? Is there any way to keep the well open long enough to hit pause on the meltwater whisking the glacier off?

These sorts of questions were to be expected with experimentation, but the team also finds itself pressed by the human uncertainty in this equation. Does humanity have it in itself to keep going, even when plagued by initial setbacks?

Besides, what’s the alternative? someone pointed out

It’ll cost a ton!

What’s cost? I said. Postdocs can be so stovepiped, it would be funny if it weren’t so alarming. I clarified reality for them: Look, if you have to do something, you have to do it. Don’t keep talking about cost as if that’s a real thing. Money isn’t real. Work is real.

Money is real, Dr. G. You’ll see.

This method is the only way that will work.

But it didn’t work! It cut out on us!

Yes, but this was just the start. If at first you don’t succeed⁠—

You’l never get funded again.

Kim Stanley Robinson, The Ministry for the Future, 2020

It’s playfully done, this highlighting of financial interests and other excuses against taking action. But the narrator’s observation about the difference between money and work comes especially to bear on the ultimate result for their efforts, which (spoiler!) see them reach a point where there’s no more meltwater to drill from their wells in Antarctica. At that juncture, the positive impacts of the work are far-ranging:

So; ten years in Antarctica, with good work to do, and no more grant applications either. Papers got written, science got done, but mostly it was engineering the drills and pumps and dispersion technologies. There were papers to be had there too, even if it wasn’t exactly what we had gone down there for. Actually the glaciologists were getting data like never before, especially structures of ice and flow histories, and most of all, bottom studies. For sure no one had ever had the kind of information about glacial ice/glacial bed interactions that we have now! If we had been doing that research only for its own sake, it would have taken centuries to learn what we’ve learned. But we had an ulterior motive, an overriding concern.

Kim Stanley Robinson, The Ministry for the Future, 2020

It’s hard not to read this paragraph in light of another field day for researchers in recent years: the absolute explosion of medical sciences as a consequence of the COVID-19 pandemic. In “Wonder of wonders, miracle of miracles: The unprecedented speed of COVID-19 science” (Physiological Reviews, 2022), this recent crisis is contrasted with other disease outbreaks that significantly accelerated human learning. So too has war routinely proven a mother of (terrible) invention. Why then shouldn’t we expect that climate change mitigation could be leveraged, like everything else, to advance individual careers and specialized knowledge?

Robinson has been considered overly optimistic in his depiction of a concerted global effort to combat meltwater to stop glaciers from eroding at quite the same pace. So too was his notion of a carbon coin, which relies on mutual consent to treat the currency as valuable, seen by some as asking entirely too much.

But in sections like the above, it’s quite clear that Robinson isn’t expecting humans to be singularly noble or altruistic. He is expecting that “the work will out”, and that competitive pressure to be part of something that might earn you, your government, or your academic institution prestige will offer its own social lubricant for processes that might otherwise happen at a (traditionally) glacial pace.

We might not work together to save the planet for its own sake.

But maybe, just maybe, our desire not to miss out on an opportunity to secure or sustain our “lead” in the murky public markets of human striving will give us a chance all the same: at the poles, and everywhere else in our changing world.

What other options do we have?