Geo-engineering glaciers: perspectives on our recent Nature comment
Last week, a team of scientists, of which I was one, published a comment in Nature arguing that proposals to geo-engineer glaciers to ameliorate their melting must take into account the downstream effects of destablising glacier ecosystems:
The writing process was very interesting for several reasons. I certainly felt that I was among very esteemed colleagues with deep expertise on glacier ecology and glaciology. It was really an honour to be included in the group and participate. I am on board with the overall message that geoengineering of glaciers should be carefully addressed, necessarily considering interactions between interlinked glacial and extraglacial environments and microbial ecosystems. I’m proud to have worked on the paper! However, I also felt I had some perspectives that contrasted with the rest of the group.
Here, I’m laying out some of those perspectives.
Note: paper writing is a deeply collaborative process - there is always some compromise and healthy disagreement, especially on tricky and controversial topics like this one. This post is in no way a gripe - I’m very grateful to have been part of this and proud of the work that was done!
Also, a disclaimer that I’m liable to use hyperbole and extrapolation to make my points here - consider the following slightly tongue in cheek.
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Glacier microbial conservation is not a compelling counterargument to geoengineering
One of the arguments that was prevalent in the drafts but was toned down in the final version was that glacier ecosystems must be protected for the ecosystem services they convey, or because glacier microbial conservation is in itself, inherently an important outcome. I consider these perspectives to be questionable, for several reasons. First, the arguments in favour of glacier microbial ecosystems being net beneficial to humans are tenuous, mainly boiling down to:
a) Net autotrophy (the idea that glacier microbes photosynthesise more than they respire, acting as a carbon sink similar to trees in extraglacial environments). However, net autotrophy is probably not the default configuration for glacial ecosystems, in fact net heterotrophy may well be the most common state when these systems are viewed year-round and across large spatial scales. I’d suggest the net autotrophy / net heterotrophy debate is unresolved, making the argument that glacier microbes should be preserved due to their role as a carbon sink quite weak. This is especially true when you consider that evben in a state of net autotrophy the capacity of the global glacier microbial ecosystem to sequester carbon is probably very small compared to other carbon sinks.
b) Glacier microbial ecosystems can be mined for valuable biomolecules. While this is possible, the bioprospecting potential of glacier microbes is largely unproven and mostly relies upon speculation that loosely specified genetic and antimicrobial compounds might exist that are unique to the glacier surface ecosystem. I’ll be interested to see any further developments in this space, but for now, speculation about possible hidden value isn’t enough to justify action to conserve these systems if that action is expensive or blocks other action that might have positive human externalities.
c) Glacier microbes are model systems for life elsewhere in the universe. While this has been said many times about several glacier microbes, I’ve become very sceptical that it is true. Glacier microbes mostly exist on glacier surfaces where water ice is melting, which is not the case anywhere in the solar system except for Earth’s glaciers in the summer. Other ice masses are frozen solid year-round and are bombarded with harmful cosmic radiation that our terrestrial organisms don’t have to deal with thanks to the Earth’s protective atmosphere. The likelihood that terrestrial supraglacial microbes are good models for life on, say Mars or Europa, seems pretty small.
So the conservationist arguments feel quite weak. At the same time, one of the best known effects of glacier microbes is their albedo-reducing (darkening) effect on the ice surface. Darker materials warm up more in the sun and melt faster. This microbial darkening is a negative externality as it accelerates glacier melting. So there’s an argument that allowing the demise of glacier ecosystems might be more beneficial for humans than sustaining them. Removing them might even be an effective geoengineering solution as it would raise the ice albedo!
I’ve been fascinated by glacier microbial life for nearly two decades and have studied them prolifically - they are beautful and fascinating. However, I would trade their wellbeing for a realistic shot at real, scalable climate change mitigation!
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2) There are much more important factors
The fact that I don’t find the microbial conservationist arguments compelling does not mean I’m necessarily in favour of glacier geoengineering. However, the pertinent arguments against it are unrelated to glacier microbial life. The most compelling counterargument, for me, is that I don’t believe anything I’ve seen proposed so far will work. The interventions I’m aware of seem likely to incur huge financial costs and possibly environmental harms without much evidence of a payoff in the form of climate mitigation. So the key argument against glacier geoengineering is not a microbial conservationist one but an economic one - the chance of payoff is very small but the costs and negative externalities (including for glacier life and its downstream connections) are probably large.
If we consider glacier loss and the associated sea level rise and albedo feedbacks to be a dreadful problem then the primary decision making factors in determining whether to carry out some intervention should be:
- Efficacy - will the solution actually work?
- Cost - is the solution more costly than the problem? Would funds have to be pulled from other critical programs?
- Maintenance burden - how sustainable is the solution? Does it rely on continual maintenance or reapplication?
- Termination shock - what happens if/when the solution stops being applied?
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3) We risk proliferating red tape and busywork
The recommendations to do expansive, longitudinal field studies, impose regulations and block private enterprises from participating all give me pause for thought. Regulation isn’t typically a good solution when the quality or speed of the outcome is consequential. In the UK we have recently had high profile examples of the failures of state bureacracy including bat tunnels, fish discos and a 14 mile road that took 66 miles of paperwork and 16 years to approve. These are emblematic of the effectiveness of state bureacracy in preventing important actions while also generating exorbitant expenses. In our example, it’s not hard to imagine a scenario where scientists call for regulation and end up in a situation where we can’t implement a climate-change solving wonder-project because of some bureacratic or legislative burden put in place to protect esoteric glacier microbes. Mitigating glacier melting could become our very own HS2.
The article implies that private initiatives are necessarily unethical and bound to monetary incentives that can’t align with positive environmental externalities. I’ll concede that there are indeed plenty of reasons to distrust commercial organisations, but perhaps not moreso than government or other non-commercial ones that are mired in their fair share of scandal and misdemeanour. Good solutions can come from anywhere, and commercial organizations are usually at least more agile. In my opinion, it’s silly to be ideological about who solves a problem, especially under the implication that only a state-managed solution is acceptable. Instead, design a set of criteria for what a good solution looks like and judge proposals on their merits: efficacy, cost efficiency and speed of delivery.
At the same time, calling for lots more research and longitudinal studies runs counter to the narrative that there is an urgent problem to solve. If the melting of glaciers and ice sheets is truly an urgent issue, and someone proposes an engineering solution to mitigate it, then blocking it due to an insufficient amount of published research into glacier microbial communities is unjustifiable. Conducting and publishing new research takes years. The speed of academia is simply not well suited to the pace of action required if the problem really is urgent. Furthermore, who defines the threshold when the body of research on glacier ecology is sufficient? A cynic might suggest this line of argument is one that benefits career researchers more than the environment they aim to preserve.
Summary
In summary, the nuances I want to highlight are the potential to overvalue glacier microbes in a cost-benefit analysis based on shaky evidence of their role as carbon sinks, fertile ground for bioprospecting or alien analogs (said even as a died-in-the-wool glacier ecology enjoyooor) and the risk that the calls for research and regulation risk counterproductive outcomes. The disaster scenario is that someone finally lands on some engineering solution with potential for real world mitigation of glacier and ice sheet melting, and it is blocked by the red tape we demanded for the protection of glacier microbes. If glacier melting is really an emergency situation and if it can really be addressed using engineering interventions, then we need to cut red tape and deregulate so we can address it at the necessary pace.
As a final thought, I am on board with the content of the paper, overall - otherwise, I wouldn’t have put my name to it. I agree that taking the downstream consequences of destabilizing glacier microbial systems into account when risk-assessing a melt-rate intervention is very important and likely to be overlooked. More thorough knowledge about these systems is a very worthwhile endeavour, I’ve got plenty of skin in that game. Glacier microbes probably are sensitive to many of the propsoed interventions and it’s true that we don’t know what the consequences of that might be. If some bioprospecting breakthrough happens, or we find that these algae wash off to play a critical role in the ocean food web, or they turn out to be a huge net autotrophic carbon sink, then I’ll gleefully rethink the positions I outlined above!