The research team, led by Aditya Sengupta of the University of Melbourne, combined two complementary modelling frameworks. The first was the Zero Emissions Commitment Model Intercomparison Project, or ZECMIP, in which nine Earth system models branch off a transient warming simulation at the point where cumulative emissions reach 1000 petagrams of carbon and then run with emissions set to zero. The second was a set of bespoke, millennial-length simulations with the Australian Earth system model ACCESS-ESM1-5, in which emissions cease at seven different points between 2030 and 2060 and the climate is then allowed to evolve freely for 1000 years. Together, these experiments let the researchers ask a question that standard climate scenarios rarely address: what happens to the tropical Pacific after humanity stops emitting?

The answer is sobering. Under transient warming, nearly all models agree that the zonal temperature gradient of the equatorial Pacific—the difference in sea surface temperature between the warm western Pacific and the cooler eastern Pacific—weakens, producing a mean state that resembles a permanent El Niño. In the ZECMIP simulations, this weakened gradient persists for decades to centuries after emissions cease, with no meaningful recovery. The global mean surface temperature stabilises at roughly 2 degrees Celsius above pre-industrial levels, but the Pacific does not bounce back to its pre-industrial configuration.

The consequences for extreme weather are equally persistent. The researchers used a metric linking the meridional temperature gradient across the eastern equatorial Pacific to local rainfall, a well-established proxy for extreme El Niño events of the kind seen in 1997/98 and 2015/16. In the unforced pre-industrial control runs, only about 9.8 percent of El Niño events in the ZECMIP ensemble were extreme. During transient warming, that share more than doubled to about 21.3 percent—and after emissions stopped, it remained at 20.25 percent. In the longer ACCESS-ESM1-5 runs, the baseline was even lower, at 1.73 percent of El Niño events, yet in the late-cessation B2060 simulation, extreme events still accounted for 26.3 percent of all El Niño events centuries after net zero was achieved. Crucially, the changes scale with warming level: the later emissions cease, the larger and longer-lived the shift.

Not every aspect of El Niño–Southern Oscillation behaviour behaves so coherently. Changes in ENSO amplitude—the typical strength of the oscillation—turn out to be non-monotonic and strongly model-dependent. Seven of the nine ZECMIP models showed amplification during transient warming, and the ensemble median stayed elevated after cessation, but the 30-year rolling time series wobbled considerably, dominated by multi-decadal internal variability. Only when the researchers applied a 100-year averaging window in the ACCESS simulations did a sustained elevation of ENSO amplitude emerge clearly from the noise, particularly in the late-cessation pathway. The forced signal, in other words, is real but only reveals itself on multi-centennial timescales.

The mechanism behind this persistence lies in the uneven way the ocean absorbs and releases heat. After emissions stop, the surface of the Northern Hemisphere stabilises or even cools, but the Southern Ocean and the deep ocean continue to warm for a very long time. This delayed warming shrinks the temperature difference between the hemispheres, which shifts the tropical convergence zones—the ITCZ and the South Pacific Convergence Zone—net equatorward and drives cross-equatorial atmospheric flow. The result is a sustained weakening of the easterly trade winds over the equatorial Pacific, which reinforces the El Niño-like background state.

Beneath the surface, the story continues into the upper ocean’s circulation machinery. During warming, the slope of the equatorial thermocline—the tilted boundary between warm surface water and cold deep water, tracked by the 20 degree Celsius isotherm—flattens, shoaling in the west and deepening in the east. After cessation, sea surface temperatures cool slightly while the subsurface keeps warming, so the flattened thermocline never recovers its tilt. The researchers also found hemispherically asymmetric changes in the Subtropical Cells, the shallow overturning circulations that carry cold water toward the equator. Anomalous low pressure and cyclonic winds over the South Pacific drive Ekman suction that slows the southern cell, reducing the upwelling of cold water, while the water that does upwell in the east is anomalously warm. Both effects inhibit any recovery of the zonal temperature gradient.

Feedback diagnostics add a final piece to the causal chain. Using linear regression, the team showed that the atmospheric wind–SST feedback strengthens during transient warming but returns to within its pre-industrial range once emissions cease—atmospheric coupling adjusts quickly. The oceanic feedbacks, by contrast, intensify and stay intensified: the thermocline–SST feedback remains elevated for centuries, meaning eastern Pacific surface temperatures become more sensitive to subsurface anomalies, and wind anomalies tilt the thermocline more efficiently. This reorganisation of oceanic feedback, combined with the persistently weakened zonal gradient and equatorward-shifted convergence zones, keeps ENSO variability amplified long after radiative forcing has stabilised.

The findings fit into a broader, non-linear picture of how ENSO responds to climate change. Palaeoclimate proxies and previous modelling work indicate that ENSO amplitude does not scale simply with warming: moderate shifts of the convergence zones under moderate warming can enhance variability, while extreme warming under very high carbon dioxide concentrations can suppress it, producing a permanent El Niño-like state with weakened variability. Net zero scenarios, which branch off at moderate warming levels, appear to sit in the amplifying regime—locking in a weakened gradient and elevated variability for centuries without ever reaching the extreme concentrations of idealised abrupt-forcing experiments. The study also differs from earlier work suggesting robust ENSO weakening under fixed high carbon dioxide, underscoring that the response depends critically on both the level and the trajectory of forcing.

The authors are careful about limitations. The millennial-scale feedback analysis rests on a single model, and ACCESS-ESM1-5 shares common biases such as a cold tongue and double ITCZ that could exaggerate eastern Pacific convection changes. Yet checks across the ZECMIP ensemble suggest the direction of the response is robust: in eight of nine models, the zonal gradient continues to weaken after cessation regardless of each model’s background state. The clear message for policy is that early mitigation matters twice over—delaying net zero not only increases the magnitude of the Pacific shift but also its persistence, committing generations to more frequent extreme El Niño events and altered rainfall patterns over regions such as East Asia and Australia. Net zero slows further change, the study concludes, but it does not restore the Pacific we knew.

Subject of Research: Persistence of an El Niño-like tropical Pacific mean state under net zero emissions due to ocean thermal inertia

Article Title: Ocean thermal inertia sustains a tropical Pacific mean state shift under net zero

Article References: Ocean thermal inertia sustains a tropical Pacific mean state shift under net zero. (n.d.). https://doi.org/10.1038/s43247-026-04082-x

Image Credits: AI Generated

DOI: 10.1038/s43247-026-04082-x

Keywords: El Niño, ENSO, net zero emissions, tropical Pacific, ocean thermal inertia, Southern Ocean, thermocline, climate modelling, ZECMIP, ACCESS-ESM1-5, extreme El Niño, ITCZ

A team led by Abigail Swann of the University of Washington, together with Charles Koven of Lawrence Berkeley National Laboratory and colleagues across fifteen institutions, analyzed simulations from ten Earth system models run under the new flat10MIP experimental protocol, an idealized framework adopted for the Coupled Model Intercomparison Project Phase 7. Unlike earlier experiments that prescribed atmospheric carbon dioxide concentrations, flat10MIP specifies emissions directly, letting each model calculate how much carbon dioxide actually accumulates in the air as its land and ocean components absorb or release carbon. That design allows scientists to probe two crucial climate metrics, the transient climate response to cumulative emissions and the zero emissions commitment, while simultaneously tracking where carbon ends up on land.

The experimental architecture is elegantly simple. In the core flat10 experiment, carbon dioxide is emitted at a constant 10 petagrams of carbon per year, close to present-day rates, for at least a century, accumulating 1000 petagrams of cumulative emissions. From that point, two branches diverge. In the zero-emissions branch, emissions drop instantly to zero and the simulation runs for another 200 years. In the carbon-dioxide-removal branch, emissions decline steadily, turn negative, and eventually reach minus 10 petagrams per year, so that by year 300 the cumulative emissions over the whole experiment return to zero. Ten models, including ACCESS-ESM1-5, CESM2, NorESM2-LM, GFDL-ESM4, UKESM1.2, MPI-ESM1-2-LR, MIROC-ES2L, CNRM-ESM2-2, NASA-GISS-E2.1-G-CC2, and HadCM3LC-Bris, completed all three scenarios.

During the positive emissions phase, the models agreed on a broad pattern: land gained carbon, on average about 246 petagrams by year 100, and the majority of that gain, roughly 60 percent, landed in vegetation rather than soil. The mechanism is familiar. Elevated atmospheric carbon dioxide enhances photosynthesis, a process represented in every model, and the carbon flows first into leaves, wood, and roots before slowly leaking into litter and soil pools. The gains were largest in the tropics and mid-latitudes, and in most models carbon accumulated on land nearly linearly with cumulative emissions, at least through the first 1000 petagrams. A few models, notably ACCESS-ESM1-5, showed the accumulation rate tapering off earlier, as tropical gross primary productivity began to saturate under heat and moisture stress.

Then the picture darkened. When emissions were cut to zero, atmospheric carbon dioxide continued to fall as land and ocean sinks kept drawing it down, but the land’s internal accounting shifted dramatically. In seven of the ten models, tropical latitudes lost carbon during the net-zero phase, and in every single model, tropical vegetation carbon declined. Meanwhile, mid- and high-latitude regions kept gaining carbon, mostly in soils. The explanation is a cruel asymmetry. As carbon dioxide concentrations fall, the fertilization effect that boosted tropical growth partially reverses, yet temperatures remain high, accelerating respiration and stressing plants in the hottest regions. The tropics, which gained the most during the emissions phase, become the biggest losers once emissions stop.

The negative emissions branch told a similar story at a different baseline. By the point of cumulative zero emissions, when all the carbon ever emitted had hypothetically been removed, vegetation carbon had declined in most models and tropical carbon had fallen in all of them, relative to the pre-industrial starting state. Mid-latitude soils and high-latitude vegetation and soils, by contrast, often ended up above their initial stocks. The similarity between the net-zero and cumulative-zero responses suggests that the same processes, faster turnover of vegetation under heat stress and the reversal of carbon dioxide fertilization, operate in both cases, just from different starting points.

Perhaps the most striking result concerns timing. Peak atmospheric carbon dioxide arrived about 15 years before net-zero emissions, and global temperature peaked roughly 6 years after net-zero. Vegetation carbon peaked a remarkably consistent 10 years after net-zero, with a spread of only about 7 years across the ensemble, suggesting that the processes governing vegetation growth and decay are represented similarly across models. Soil carbon was another matter entirely. Its peak arrived on average 33 years after net-zero, but ranged from 9 years before to a staggering 126 years after, with GFDL-ESM4’s late peak reflecting its unusual soil model in which turnover slows as productivity rises. Because the zero emissions commitment depends on century-scale carbon sink behavior, this soil carbon disagreement directly undermines confidence in projecting how much warming will persist after emissions stop.

The study also exposed uncomfortable gaps in what the models actually contain. Pre-industrial land carbon stocks varied enormously, from 978 petagrams in GFDM-ESM4 to 3119 petagrams in NorESM2-LM, against an IPCC benchmark of about 3350 petagrams for the present day, and many models appear to hold too little soil carbon, particularly in high latitudes where permafrost processes are missing from most land components. Only three models resolve soil carbon by depth, and just two of those represent permafrost; both showed stagnation or losses of high-latitude soil carbon under zero emissions, consistent with warming-driven permafrost thaw. Even more puzzling, none of the structural differences the team examined, whether nutrient limitation, dynamic vegetation, fire, or soil complexity, correlated with model behavior. Models with and without nitrogen cycling, with one soil pool or eighty, spread across the full range of outcomes, implying that parametric uncertainty and unrepresented processes swamp the visible architecture.

That last point carries a warning for carbon dioxide removal efforts. The models in this study lack many mechanisms that would make tropical losses worse: heat damage to enzymes and reproduction, hydraulic failure and mortality, pests and pathogens, and some fire-related disturbances. The simulated tropical declines are therefore likely underestimates. And because most afforestation and reforestation projects are planned for low latitudes, precisely the regions where the models show carbon being gained and then lost, the study raises the prospect that tree-planting schemes could see their stored carbon evaporate under the sustained heat of a zero-emissions world. The idealized flat10MIP scenarios also impose removal as a boundary condition rather than modeling the physical side effects of specific removal methods, which could add further complications.

The takeaway is sobering but precise. Tropical carbon is the most likely to be gained during rising emissions and the most likely to be lost under zero, declining, and negative emissions, making it a fragile foundation for net-zero accounting. Mid- and high-latitude soils, meanwhile, behave more reliably but on timescales so uncertain and so model-dependent that they dominate the spread in the zero emissions commitment. As nations design removal portfolios and net-zero pledges, the message from this ten-model ensemble is clear: stopping emissions does not stop the carbon cycle from rearranging itself, and the places we most depend on to store carbon may be the places least able to keep it.

Subject of Research: Land carbon sink responses to positive, zero, and negative CO2 emissions across Earth system models

Article Title: Land carbon response to positive, zero, and negative CO2 emissions across Earth system models

Article References: Swann, A. L. S., Koven, C. D., Proistosecu, C., Fisher, R. A., Sanderson, B. M., Brovkin, V., Hajima, T., Jones, C. D., Kiang, N. Y., Lawrence, D. M., Liddicoat, S., Liddy, H., Romanou, A., Séférian, R., Sentman, L. T., Steinert, N. J., Tjiputra, J., & Ziehn, T. (2026). Land carbon response to positive, zero, and negative CO 2 emissions across Earth system models. Earth System Dynamics, 17(5), 1237-1275. https://doi.org/10.5194/esd-17-1237-2026

Image Credits: AI Generated

DOI: 10.5194/esd-17-1237-2026

Keywords: land carbon sink, Earth system models, net-zero emissions, negative emissions, tropical forests, soil carbon, CO2 fertilization, flat10MIP, zero emissions commitment, carbon dioxide removal, permafrost, climate modeling

The core of the problem lies in a mismatch between two very different modeling worlds. Integrated assessment models, or IAMs, simulate the global economy, energy systems, agriculture, and land use, and they decide where and when carbon removal technologies should be deployed based on costs, resource demands, and policy assumptions. Earth system models, or ESMs, simulate the physics, chemistry, and biology of the atmosphere, ocean, and land surface in fully coupled detail. In the current state-of-the-art setup, used for the fifth and sixth phases of the Coupled Model Intercomparison Project and planned again for the seventh, the IAM simply hands the ESM a net emissions number in which the carbon removed by technologies like bioenergy with carbon capture and storage is folded in as a prescribed negative flux. The Earth system model never sees the bioenergy crops growing, never simulates the forests being planted, and never computes the ocean chemistry changes caused by dumping alkaline material into the sea. Everything the model does in response to that removal is therefore invisible.

Schwinger and colleagues argue that this prescribed approach must give way to what they call activity-driven simulation of carbon dioxide removal. Instead of prescribing a negative emission, the ESM explicitly represents the activity that draws down atmospheric CO2. For bioenergy with carbon capture and storage, that means growing the crops inside the model, harvesting the biomass, and routing a scenario-dependent fraction of the harvested carbon into geological storage. For ocean alkalinity enhancement, it means adding an alkaline agent such as slaked lime to the surface ocean and letting the model’s carbonate chemistry, circulation, and biology determine how much CO2 is actually sequestered, and how quickly. Only afforestation and reforestation have always been simulated this way, because the land-use patterns passed from IAMs to ESMs implicitly contain the forest transitions. Extending the same philosophy to other methods harnesses the full power of Earth system models: climate change effects on removal efficiency, from drought stress on bioenergy crops to ocean circulation changes, are computed rather than assumed.

But simulating the activity is only half the challenge. To measure what carbon removal actually achieves, scientists need a reference against which to compare, and this is where the study makes its most consequential conceptual contribution. The team defines two distinct metrics. The first is Process Carbon Removal, the gross amount of carbon a removal process takes up minus its own positive emissions, without any feedback effects. This is essentially what IAMs estimate, and it is the quantity relevant for carbon accounting, in the same way that emissions are priced per tonne regardless of how natural sinks respond. The second is Net Atmospheric Removal, the true difference in atmospheric carbon content between a world with the removal technology and a world without it, including every carbon-cycle and biogeophysical feedback the Earth system can muster. Crucially, the authors show that these two numbers can diverge substantially, because the planet’s carbon sinks respond to removal in ways that partially undo the benefit.

The reason for that divergence is the buffering nature of the carbon cycle. Today, terrestrial and oceanic sinks absorb more than half of every tonne of CO2 humanity emits. Models project that under declining emissions these sinks will take up less carbon, and under net-zero or net-negative emissions they can even flip into carbon sources, releasing CO2 back to the atmosphere as the reversed feedbacks operate in reverse. The practical consequence is stark: the net atmospheric reduction achieved by any carbon removal portfolio will always be less than the gross amount removed. How much less is a question the new framework is designed to answer quantitatively, scenario by scenario and model by model.

Constructing the necessary no-CDR baseline turns out to be anything but trivial. The authors distinguish two fundamentally different approaches. The first is an ex-post adjustment: take an existing IAM mitigation scenario and surgically remove the carbon removal, for instance by freezing the land-use transitions associated with afforestation or by omitting the alkalinity flux to the ocean. This preserves the original scenario’s geography and allows regional attribution of effects, but it produces a socio-economically inconsistent world, one where land earmarked for bioenergy simply sits idle rather than being reallocated to food production. The second is a counterfactual IAM scenario: re-run the economic model in a world where carbon removal was never an option, letting the energy system, land use, and emissions evolve consistently without it. This counterfactual world is socio-economically coherent but so different in its land-use and emissions geography that regional biogeophysical effects of the original removal deployment cannot be isolated. The two approaches are complementary, and the authors recommend that IAM teams begin producing counterfactual no-CDR baselines for selected scenarios, something that, to their knowledge, does not yet exist in the scenario literature.

To demonstrate the framework in action, the team turned to the Norwegian Earth System Model NorESM2-LM and a deep mitigation scenario generated by the REMIND-MAgPIE integrated assessment model, expanded to include ocean liming as a removal method. The scenario reaches an end-of-century carbon budget of 500 gigatonnes of CO2 from 2020, corresponding to 1.5 degrees Celsius of warming in 2100 after a substantial overshoot, with a peak cumulative budget exceeding 1000 gigatonnes around 2060 before massive upscaling of removals pulls it back down. In the Earth system model, ocean alkalinity enhancement was simulated activity-driven, with alkalinity deployed within exclusive economic zones excluding polar regions, while bioenergy removals remained prescribed. Three ensemble members were run for each of the required simulations.

The results are striking and, for anyone banking on ocean-based removal, sobering. For a deployment of 4.93 petamoles of alkalinity between 2050 and 2100, equivalent to 182.5 gigatonnes of calcium hydroxide, the model simulated a Process Carbon Removal of 28.2 petagrams of carbon by 2100. Carbon-cycle feedbacks from both land and ocean then clawed back 7.9 petagrams, roughly 28 percent, leaving a Net Atmospheric Removal of just 20.3 petagrams of carbon, equivalent to a 9.7 parts-per-million reduction in atmospheric CO2. The ocean and terrestrial biosphere contributed roughly equally to the feedback losses, at 4.8 and 3.1 petagrams respectively, though the authors caution that the land feedback in particular may vary greatly between models. Equally revealing was the comparison with the IAM’s own estimate: REMIND-MAgPIE, which assumes a constant efficiency of 0.57 moles of CO2 per mole of alkalinity and instantaneous uptake, overestimated the removal by about 7.4 petagrams, roughly 20 percent, partly because real ocean chemistry takes ten to fifteen years to fully equilibrate an alkalinity addition.

Perhaps the most humbling finding concerns the noise floor of the climate system itself. Even a tiny initial difference in carbon removal deployment acts as a perturbation that causes the scenario and baseline simulations to diverge chaotically, exactly as separate ensemble members with different initial conditions do. Within a few years of the alkalinity deployment beginning around 2040, the El Niño-Southern Oscillation states of the two simulations had become completely uncorrelated. The resulting internal variability in calculated removals and feedback fluxes remained comparable in magnitude to the global annual mean signal, and even decadal averages carried a noise level exceeding 0.25 petagrams of carbon per year. The implication is uncomfortable: detecting the small signals associated with carbon removal and its feedbacks in emission-driven simulations requires either sufficiently large initial-condition ensembles or averaging over long periods, and for some applications, such as quantifying regional biogeophysical effects, stylized modeling approaches may simply remain preferable.

The timing of this work could hardly be better. The upcoming seventh phase of the Coupled Model Intercomparison Project has adopted emission-driven scenario simulations as a priority, yet its ScenarioMIP protocol still foresees only prescribed carbon removal and no no-CDR baselines, limiting what those simulations can say about removal effectiveness. The authors argue that the next phase of the Carbon Dioxide Removal Model Intercomparison Project should adopt their framework, and they issue concrete recommendations to the modeling community: IAMs should provide gross positive and negative emissions separately for each removal method, deliver spatially explicit information on bioenergy with carbon capture in future land-use datasets, and flag the difference between passive forest regrowth and deliberate afforestation. As nations and companies commit billions to carbon removal portfolios whose real-world performance remains deeply uncertain, this framework offers something the field has lacked: a transparent, physically consistent way to separate what a removal technology promises from what the Earth system actually delivers.

Subject of Research: Earth system modeling of carbon dioxide removal efficiency and feedbacks in mitigation scenarios

Article Title: Assessing Earth system responses in mitigation scenarios with activity-driven simulation of carbon dioxide removal

Article References: Schwinger, J., Merfort, L., Bauer, N., Bernardello, R., Butenschön, M., Bourgeois, T., Gidden, M. J., Gupta, S., Lee, H., Mengis, N., Moustakis, Y., Muri, H., Nieradzik, L., Peano, D., Pongratz, J., Sauer, P., Tourigny, E., & Wårlind, D. (2026). Assessing Earth system responses in mitigation scenarios with activity-driven simulation of carbon dioxide removal. Earth System Dynamics, 17(5), 1341-1363. https://doi.org/10.5194/esd-17-1341-2026

Image Credits: AI Generated

DOI: 10.5194/esd-17-1341-2026

Keywords: carbon dioxide removal, Earth system models, integrated assessment models, ocean alkalinity enhancement, BECCS, afforestation, carbon cycle feedbacks, no-CDR baseline, CMIP7, net-zero emissions, NorESM2, climate mitigation scenarios

The scale of the problem the material targets is considerable. Industrial activity, including the burning of fossil fuels for energy, accounts for a substantial share of the carbon dioxide accumulating in Earth’s atmosphere. In the United States alone, the Environmental Protection Agency estimates that roughly 30 percent of total greenhouse gas emissions come from industry. Capturing carbon dioxide at the point where it enters the atmosphere, before it can disperse and contribute to global warming, is widely regarded as one of the more practical avenues for mitigating climate change, because point-source technologies are comparatively mature compared with the still-nascent field of direct air capture.

Metal-organic frameworks, or MOFs, are the class of materials at the heart of the new study. They are crystalline solids built from positively charged metal ions surrounded by organic linker molecules known as ligands. The metal ions act as nodes that bind the arms of the linkers, assembling a repeating, cage-like architecture riddled with nanosized pores. Those pores behave something like a molecular sponge, adsorbing gas molecules onto their interior surfaces. Because chemists can swap out the metal nodes and the organic linkers almost at will, the design space is enormous: researchers have already synthesized more than 100,000 distinct MOFs, and the properties of hundreds of thousands more have been predicted computationally.

That structural versatility is precisely why MOFs have long been considered promising candidates for carbon capture. Kyriakos Stylianou, professor of chemistry in the Oregon State University College of Science and director of the university’s Materials Discovery Laboratory, known as the MaD Lab, has emphasized that capturing carbon dioxide is critical for meeting net-zero emission targets and that MOFs have shown considerable promise thanks to their porosity and adaptability. Yet the same porous interiors that make MOFs effective adsorbents also make them vulnerable. In many promising materials, water molecules compete with carbon dioxide for the same adsorption sites, and in humid conditions the water wins, effectively shutting down the capture process.

BVR-X sidesteps this failure mode through an unusual internal organization. Rather than allowing water and carbon dioxide to compete for the same space, the material directs the two molecules to different regions inside its pores, a strategy the researchers describe as pore compartmentalization. Water is shepherded away from the sites where carbon dioxide is captured, so moisture no longer blocks the adsorption chemistry. As Stylianou explained, this internal organization helps the material work under conditions that more closely resemble real industrial emissions, where humidity is not an inconvenience to be engineered away but a constant feature of the gas stream.

The implications of that design choice are economic as much as scientific. Flue gases can, in principle, be dried before they reach a capture bed, but dehumidifying enormous volumes of exhaust adds significant expense, enough to render the carbon dioxide removal process nonviable for many industrial applications. A material that tolerates or even exploits humidity removes that cost barrier entirely. Stylianou noted that water usually makes capturing carbon dioxide more difficult, but that the new material responds to water by changing in a way that lets it keep capturing the greenhouse gas effectively even under very humid conditions, an adaptive behavior that sets it apart from conventional adsorbents.

Laboratory testing put that claim to the test under deliberately challenging conditions. The MOF efficiently captured carbon dioxide from a highly humid stream containing just 4 percent carbon dioxide, a composition relevant to emissions from natural gas combustion. Separating a small amount of carbon dioxide in the presence of substantial water is particularly challenging, Stylianou observed, which makes the result especially relevant for gas-fired power plants and similar facilities. A dilute, wet gas stream is close to a worst-case scenario for many adsorbents, and demonstrating strong performance there suggests the material is built for the messiness of real smokestacks rather than the tidy conditions of a laboratory bench.

Durability and reusability, the qualities that determine whether a laboratory curiosity can become an industrial workhorse, also feature prominently in the findings. According to the researchers, the material can be regenerated and reused, maintaining its performance through dozens of capture-and-release cycles while tolerating demanding conditions. Regeneration, the step in which captured carbon dioxide is released so the adsorbent can be used again, is central to the economics of any capture technology, since a sorbent that degrades after a handful of cycles would need constant replacement. Sustained performance across repeated cycles, combined with tolerance for the heat and chemical variability of flue gas, are important qualities for practical carbon capture technologies.

The study was a collaborative effort. Working alongside Stylianou were MaD Lab members Ankit Yadav, Emmanuel Musa and Andrzej Gładysiak, along with Micah Hickethier, Chun-Wai Chang and Kai Shen Choong of the Oregon State College of Engineering. Scientists from the University of California, Berkeley, the University of Oregon and the ARAMCO Research and Development Center also contributed. Funding came from Saudi Aramco, the Murdock Charitable Trust, and the donor-advised fund of Oregon State alumni and retired public school teachers Brian and Marilyn Kleiner through the OSU Foundation. Saudi Aramco applied for a patent on the synthesis and carbon dioxide capture properties of BVR-X, with several of the researchers listed as co-inventors.

The advance arrives at a moment when the world’s carbon removal infrastructure remains soberingly small. Facilities that filter carbon directly from ambient air are beginning to appear around the globe, including the world’s largest such plant, which opened in Iceland in 2024, but as Stylianou notes they are not yet capable of making a large dent in worldwide emissions; in a year, that Icelandic plant can draw out carbon dioxide in quantities comparable to the annual emissions of roughly 7,200 cars. Point-source capture at factories and power plants, where carbon dioxide is far more concentrated, offers a nearer-term path, and materials like BVR-X, which thrive in the humid, dilute conditions of real exhaust streams, could help close the gap between laboratory promise and industrial deployment in the race toward net-zero emissions.

Subject of Research: A water-tolerant metal-organic framework for industrial carbon capture

Article Title: New material developed at Oregon State provides boost to carbon capture technologies

Article References: New material developed at Oregon State provides boost to carbon capture technologies. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: carbon capture, metal-organic frameworks, MOFs, flue gas, carbon dioxide, greenhouse gas emissions, Oregon State University, adsorption, climate change mitigation, porous materials, net-zero emissions, industrial emissions