Fields of seaweed expand to the ocean’s horizons. During the day the kelp draws carbon from the air. At night the drones to which it is tethered lower it below the surface to absorb nutrients. When the drones sense a field is ready for harvesting it is towed to processing plants where bioethanol fuel is extracted. Carbon produced during the process is captured and stored underground.

Further inland cattle graze on open plains, with no farming machinery in sight. Herds till the earth with their hooves and move on. Seeds are planted in the rich soil they leave. When the fields are farmed the crop residues, saturated with the carbon the land has absorbed, are gathered and combusted to make biochar, a kind of charcoal that can be taken to cement plants to be mixed with aggregates to make carbon absorbent concrete. The carbon emitted by the cities of the past becomes building material for the cities of the future.

Is this geoengineering? Both of these systems are designed to alter the Earth’s climate, to draw carbon from the atmosphere and to cultivate new sources of fuel at scales capable of powering advanced economies. But they seem far from the popular images climate intervention conjures: sunshades in space, planes spraying particles into the stratosphere, tankers dumping iron into the ocean to fertilise algae blooms.

Promethean schemes for calibrating the infinite complexities of the Earth’s natural systems have dubious scientific and political foundations. Even the most thoughtful liberal commentaries on climate intervention, such as Oliver Morton’s influential The Planet Remade (2015), seem mesmerised by visions of a geoengineered ‘technological sublime’,¹ a complex of technologies acting as a global thermostat that can be calibrated as required to ‘move the earthsystem’,² unobtrusively cleaning up the mess produced by a carbon-fuelled global market that simply powers on.

Andreas Malm observes that for Morton geoengineering is “an attempt to treat the entire climate system as though it were a machine.”³ For Naomi Klein speculative climate interventions are a distraction from the long, hard process of system change, underlining “the urgent need for a real plan A - one based on emission reduction, however economically radical it must be.”⁴ And Geoff Mann and Joel Wainwright’s Climate Leviathan⁵ questions how these complex technologies, whose use and effects transcend national borders, could be brought under democratic control. Drawing on the image of the Biblical whale and Carl Schmitt’s authoritarian political philosophy, Mann and Wainwright anticipate the likelihood that as climate change worsens an elite group of nations— indeed, probably just the United States and China—will declare an indefinite ‘state of emergency’ during which they will arrogate to themselves the sovereign authority to design and manage climate intervention programmes on behalf of all of us.

Geoengineering has hardly featured in flagship ecosocialist climate change initiatives. Alexandria Ocasio-Cortez’s Congressional resolution for a Green New Deal made only passing reference to carbon drawdown technologies. And there is no reference at all in the most comprehensive version of the Deal yet proposed, Bernie Sanders’s $16 trillion programme, which focuses exclusively on investment in renewables, dismissing ‘false solutions like nuclear, geoengineering, carbon capture and sequestration, or trash incinerators’.

In her new book After Geoengineering, Holly Jean Buck, a fellow at UCLA’s Institute of the Environment and Sustainability, goes—gently—against the grain, making a subtle plea to progressives to reconsider a geoengineering. Buck defines geoengineering as a concept covering a diverse set of emerging technologies that suggest techniques for sustainable management of the Earth’s ecosystems, and acknowledge the hard truth that climate change targets require the drawing of carbon from the atmosphere as well as prevention of its further accumulation. For Buck, geoengineering is one of several vital tools necessary to address the urgency of the climate crisis, and should not be conceded to economic liberals. We should, she argues, understand climate engineering not as simply “technology”, but “as a variety of practices that include people in various relationships with nature and each other.”⁶

She notes that we already intervene, every day, to adjust the climate—only not by design. Our emissions not only heat the atmosphere through carbon build-up, but have a cooling effect, creating a film of particles that works to block sunlight just as if it was deliberately injected through some form of solar geoengineering. Climate intervention seeks to bring this process under control, to manage the ratio of energy coming in and going back out.

And the urgency of our situation requires significant climate intervention. Some 2,200 gigatons (Gt) of CO² and other greenhouse gases have been released since the Industrial Revolution. Releasing another thousand this century would raise temperatures by another two degrees Celsius. We are currently emitting 50 Gt of CO² and other greenhouse gases every year, generating another 1,000 Gt over the next 20 years. To hit the target of 2°C warming, let alone the Paris Agreement target of 1.5°C, a substantial withdrawal of carbon from the atmosphere will be necessary, as well as reducing emissions to net zero. Buck argues that ecosocialists must be open to the imaginative proposals for intervention that continue to proliferate, and to reconceiving those interventions as long-term forms of stewardship managed through democratic frameworks.

The most elegant, perhaps, are the ‘natural climate solutions’ that seek to restore and enhance the Earth’s natural capacities to absorb carbon. These include the well-established practice of afforestation, the repurposing of land for new woodlands to serve as natural carbon sinks. Less familiar is the cluster of evolving farming practices, grouped under the term ‘regenerative agriculture’, for restoring the degraded capacity of the world’s soil to absorb carbon.

Soil holds vast amounts of CO²—three times that currently in the atmosphere—although its absorbency has deteriorated since mass farming began. But this can be rehabilitated through simple measures. Rather than being cleared away, crop residues can be allowed to sink back into and thereby enrich soil. Fields can be seeded with crop strains that can store more carbon. And gentler tilling methods—grazing cattle for example—can give soil more time to recover. Crop residues not only nurture soil but can be combusted to make biochar, a useful element in cement and concrete aggregates. Restoration of the world’s wetlands, one third of which have been lost over the past century, will also help. Peatlands, tidal marshes, salt marshes and seagrasses are deep sinks into which layers of carbon can subside.

But, although fundamental to any long-term sustainable ecosystem, natural climate solutions are insufficient for the immediate challenge of carbon drawdown. Buck calculates that even their improbably swift and extensive adoption would remove only some 10 to 20 gigatons of CO² equivalent each year, and the capacity of these natural carbon sinks would be exhausted in half a century.

Their use must be supplemented, therefore, with the wide-scale deployment of some less organic drawdown technologies, most notably carbon capture and sequestration (CCS)—the removal of carbon at the source of energy production and its burial underground. CCS will have to be rapidly scaled. The International Energy Agency (IEA) estimates that some 3,500 CCS plants are needed by 2050 to absorb sufficient carbon to enables us to meet a 2°C target. There are currently fewer than 20.

CCS is complicated by its close association with the oil and gas sector, which has identified it as the key technology for legitimating their continued exploration for and extraction of fossil fuels. The hydrocarbons industry is ideally positioned to appropriate the technology, having ready access to the expertise and infrastructure required to inject carbon into caverns or depleted oil wells.

But CCS can be reconceptualised as a technique for use with cleaner fuels. Buck dwells on Bioenergy Carbon Capture and Storage (BECCS) technologies, which supersede the now discredited idea of burning plants and wood pellets as substitutes for fossil fuels. BECCS seeks to address the fundamental problems with the original biofuel concept: the diversion of vast quantities of crops and trees from other valuable uses, and the fact that burning them still emits carbon, just as burning fossil fuels does. BECCS can use biofuels that involve much less opportunity cost, such as algae and seaweed. And, crucially, carbon emissions are captured at the point of burning.

Buck also acknowledges that there might be progressive potential for solar geoengineering, those seemingly hubristic schemes for reducing global temperatures by blanketing the atmosphere through precisely-calibrated aerosol bursts. Buck suggests the idea could be employed selectively to prevent the extinction of particular ecosystems. Marine cloud brightening (a localised form of stratospheric injection), for example, might arrest the rapid deterioration of the Great Barrier Reef. Salt particles sprayed into the air immediately above the reefs could brighten local cloud formations, cooling the waters sufficiently to retain the algae on which the corals feed. It’s messy, but emergency measures like these could keep fragile systems on life support during a worldwide decarbonisation process.

Buck’s willingness to venture into the fraught territories of CCS and solar engineering brings into focus the deep question moving just below the surface of her text: the capacity and willingness of progressives to develop strategies and democratic frameworks for managing the application of complex technologies on a global scale. To that extent, she is in sympathy with arguments for the emancipatory potential of technology, popularised in recent books by Nick Srnicek and Alex Williams, Leigh Phillips and Michal Rozworski, Peter Frase, Aaron Bastani and others. Quoting the Xenofeminist collective Laboria Cuboniks, Buck appeals for a climate politics that is

proportionate to the monstrous complexity of our reality, a reality cross-hatched with fibre-optic cables, radio and microwaves, oil and gas pipelines, aerial and shipping routes, and the unrelenting, simultaneous execution of millions of communication protocols with every passing millisecond.

But Buck is less interested in salvation by technology than breaking down binaries that risk conceding the concept climate intervention to the right: geoengineering versus ecological purity; ‘capitalist’ techno-fixes versus ‘ecosocialist’ organic change; elitist technocracy versus democratic pastoralism; technology versus nature:

We need creativity, both technologically and socially; to think beyond the boxes of capitalist economics, on one hand, and binary formulations, on the other … People will accuse new ideas involving technology of planting false hopes. But the hope doesn’t inhere in the technology—it inheres in the people who would craft it.⁷

In feeling for a world ‘after geoengineering’, Buck breaks another binary: that of essay versus fiction. The argument is interleaved with microfictions imagining a future world in which climate intervention technologies have been folded into everyday, participative processes for managing sustainable energy systems. Workers at a co-operative biorefinery quarrel over the mix of plants that should be nurtured for fuel; a floating cafe bar serving workers at a seaweed farm is caught up in the storms that continue to ravage a climate system made volatile by past carbon build-up; engineers debate how to decommission a CCS plant with its vast infrastructure of pipes and old oil fields once its storage capacity has been saturated.

After Geoengineering is a book to be read on its own terms: an attempt to open up a critical dimension of the climate change discussion in which the left should participate. The book does not present a programme in the style of the recent powerful wave of manifestos for a Green New Deal from Klein, Ann Pettifor, and Kate Aronoff, Alyssa Battistoni, Daniel Aldana Cohen and Thea Riofrancos. Nor does it dwell on conundrums of strategy: those critical questions, contemplated by Mann and Wainright, of how to implement and manage climate intervention.

Rather, Buck’s eloquent and useful text seeks to disentangle a varied and complex cluster of technologies from the intimidating labels of ‘climate intervention’ or ‘geoengineering’. Many of those technologies are available now, and will be essential tools for addressing and mitigating climate breakdown. Ecosocialists need to evolve strategies for using them wisely. There are plenty of others ready to employ them for their own ends.

Holly Jean Buck’s ‘After Geoengineering: Climate Tragedy, Repair, and Restoration’ is published by Verso Books.