Editorial: Environmental geotechnology in a changing climate: challenges and opportunities

Climate change is no longer a distant boundary condition for our work – it is a first-order design variable, reshaping the performance requirements, and liabilities of the systems geoenvironmental engineers design and manage. Rising atmospheric carbon dioxide (CO2) concentrations and persistent global emissions are driving more frequent and severe extremes, with measurable economic consequences and fast-growing pressures on infrastructure performance, durability, and risk governance.For geoenvironmental engineers, this matters in practical, project-level terms. The waste and wastewater sectors remain material sources of methane and nitrous oxide, and decarbonising them requires changes in technology choice, energy sourcing, and operational control – not just policy intent. At the same time, decarbonising the built environment demands credible embodied-carbon data and defensible accounting methods – especially where product-specific emissions are often approximated or substituted, undermining procurement and design decisions. So, the challenge is clear: we must design ground–environment systems that both adapt to climate impacts and actively contribute to mitigation – through verified emission reductions, circular resource pathways, and scalable carbon management in the subsurface and within infrastructure materials.The editorial board selected “Environmental geotechnology in a changing climate: challenges and opportunities” as this issue’s theme title because it captures a defining shift in our discipline: climate change is simultaneously a stressor (higher hazard loads, changing hydroclimate, long-term deterioration mechanisms, and environmental pressures) and a design driver (decarbonisation of waste, water, remediation, and materials; deployment of CCUS; transparent carbon accounting, etc.). The title deliberately frames not only “challenges” but also “opportunities”, because geoenvironmental engineering is uniquely positioned to deliver solutions at scale: environmental systems can reduce emissions; industrial by-products can store carbon dioxide; low-carbon materials can lower project footprints; and new analytical tools can reduce environmental risks in emerging energy-geotechnics applications.Climate adaptation and mitigation have been priorities for Environmental Geotechnics since the journal’s inception. From the inaugural editorial (Singh, 2014) and the earliest issues (Khabbaz and Fatahi, 2016; Osselin et al., 2015), the journal has consistently foregrounded climate-responsive research – and the present issue builds directly on that foundation. This issue centres on mitigation: decarbonising the assets, materials, and processes that underpin modern society. A forthcoming themed issue will complement this focus by turning to adaptation, with emphasis on designing and maintaining infrastructure that remains functional under intensifying hazards. Together, these paired themes reaffirm the journal’s long-standing commitment to climate action. An emphasis that aligns strongly with several UN SDGs: SDG 13 (Climate action) is explicit across the issue, while SDG 6 (Clean water and sanitation), SDG 9 (Industry, innovation and infrastructure), SDG 11 (Sustainable cities and communities), and SDG 12 (Responsible consumption and production) are all directly advanced by the technologies and decision frameworks presented it this themed issue.We have ordered the five papers in this issue to move from “why this matters” to “how we implement,” and then to “what comes next” – linking climate drivers, decarbonisation pathways, decision tools, and frontier geotechnology.We open with Paleologos et al. (2026a) because it delivers the system-level “why now”, linking climate change to escalating economic impacts and infrastructure risk, and positioning CCUS as a near-term, high-priority mitigation measure during the transition away from fossil-fuel-based processes. The authors review the maturity of key capture routes (post-combustion, pre-combustion, oxyfuel, chemical looping, and direct air capture) before moving to what geoenvironmental engineers most directly control: utilisation and storage pathways, mineralisation using industrial materials, carbon dioxide as a geothermal working fluid, and the geomechanical and monitoring constraints that ultimately govern subsurface storage performance. Crucially, they highlight long-tail liability and insurability as an often-ignored, practical deployment gate – sitting alongside geomechanics and monitoring as a real-world constraint on scaling storage.That framing sets up the rest of the issue with a clear point: decarbonisation is not only about technology availability; it is about deployability, which depends on risk governance, monitoring, and system integration. This leads naturally into Paleologos et al. (2026b), who ask where geoenvironmental engineers can deliver measurable emissions reductions now – across waste, wastewater, and remediation.Paleologos et al. (2026b) translate decarbonisation into the operational reality of geoenvironmental systems. Focusing on methane (CH4) and nitrous oxide (N2O), they compare how the USA, EU, and China have pursued different pathways in municipal solid waste (MSW) and liquid waste management. Their message is practical: policy direction matters, but so do engineering and technology choices. They show that MSW decarbonisation has progressed further (e.g. landfill-gas capture and diversion), while wastewater decarbonisation is lagging, with persistent or rising nitrous oxide emissions and limited uptake of approaches that could shift treatment towards net-zero performance. They also emphasise that remediation footprints can vary dramatically by technology choice, and that renewable energy sourcing and lower-energy approaches can materially reduce emissions.Komine et al. (2026) then shift the narrative from reducing sources to creating sinks, proposing a scalable concept: using the mass and footprint of disposal infrastructure to drive carbon mineralisation. They develop and apply a constant-flow aeration carbon dioxide-fixation test, compile datasets for industrial by-products, and demonstrate facility-scale estimation of capture potential – illustrating what “scale” can mean by comparing estimated capture to forest sequestration equivalence. This also highlights a critical implementation issue: climate claims must be supported by transparent accounting and verified data, which leads directly to the contribution by Xue, Pokharel and Lin.Xue et al. (2026) tackle the data problem that routinely weakens carbon-informed decisions: embodied-carbon inputs for geosynthetics are often missing or substituted with generic values. They review calculation approaches, provide a geogrid example, and strengthen the evidence base by analysing 120 EPDs to propose representative regional values. Beyond the numbers, the authors provide a practical calculation method that can help industry estimate product EC without requiring commercial life cycle assessment software – an important step towards reproducible, comparable carbon reporting.In line with that emphasis on robust quantification, Yu and Uchida (2026) carry the principle into a frontier energy-geotechnology application requiring coupled thermo-hydro-chemo-mechanical analysis under environmental constraints. They employ multiphysics coupled numerical analysis to quantify reinjection effects in gas hydrates fields with regards to productivity and deformation. The results are nuanced and decision-relevant: re-injection can improve gas production and enhance hydrate dissociation, but it may induce heave and differential displacement near injection wells, raising stability concerns. The authors also explore heated produced-water injection, showing how thermal stimulation can further enhance dissociation but may drive larger expansion and risk, reinforcing that “more production” and “stable ground response” do not automatically align without careful multiphysics evaluation.Across the five papers, one message is clear: climate-aligned geoenvironmental engineering only delivers when performance and risk are quantified together – spanning emissions, materials, geomechanics, and long-term safeguards – so that solutions are not just innovative, but practical at scale. Building on this momentum, Environmental Geotechnics invites submissions to four forthcoming themed issues that extend the agenda from decarbonisation into circularity, hazard resilience, and nature-based innovation:We are grateful to all authors who contributed to this themed issue. We hope the work collected here sparks new ideas, accelerates research, and deepens collaboration on climate-aligned geoenvironmental engineering.