Inés Camilloni, professor at the University of Buenos Aires and senior researcher at CONICET, recently spoke with One Earth about the science, uncertainties, justice implications, and governance challenges surrounding solar radiation modification. The views expressed are her own and do not necessarily represent those of the University of Buenos Aires or CONICET.
Solar radiation modification (SRM) is moving from a largely theoretical proposition toward an increasingly active field of research. Models have revealed its potential to reduce some climate risks, while exposing major uncertainties over regional impacts, ecosystems, and societal consequences. Progress may require new observations and experiments, improved models, sustained international research capacity, and approaches that account for how risks, benefits, and research priorities are distributed. In this Voices, we ask: what advances are most needed to produce decision-relevant knowledge on SRM?
Afforestation and reforestation are central to climate mitigation, yet their feasibility and viability depend on more than biophysical suitability. Without considering socioeconomic constraints, carbon dioxide removal (CDR) assessments risk mistaking biophysical potential for deployable removal, obscuring where projects can succeed and which investments are needed for durable, equitable implementation. Here, we combine an assessment of 200 studies with 78 machine-learning models to quantify socioeconomic associations with standing afforestation and reforestation and assess implications for future CDR. Poverty, food insecurity, insecure land tenure, and weak governance emerge globally as the most important constraints, alongside inadequate forestry infrastructure and stakeholder support. Approximately 73% of biophysical afforestation and reforestation carbon removal potential lies in countries facing medium-to-high socioeconomic constraints. These results show that socioeconomic feasibility and viability must be integrated into removal assessments, with poverty reduction and effective institutional capacity treated as enabling conditions for equitable and durable climate action.
Lithium-ion batteries (LIBs) underpin the clean energy transition, yet their supply chains remain carbon-intensive and risk becoming a major source of greenhouse gas (GHG) emissions. Supply-side decarbonization is therefore crucial, but can it curb emissions fast enough as demand grows globally? Combining dynamic material flow analysis and life cycle assessment, we show that annual GHG emissions from the global LIB supply chain could rise more than 10-fold over 2024–2050. While supply-side strategies lower GHG intensity substantially, cutting cumulative emissions by 3.5–4.7 Gt CO2-eq, they face mitigation limits from technical ceilings, deployment dynamics, and cross-strategy interactions. Demand-side strategies are essential to further constrain supply-chain emissions, unlocking 6.0–7.2 Gt CO2-eq of cumulative mitigation beyond what supply-side decarbonization alone can achieve. Demand-side strategies also consistently lower broader environmental impacts (e.g., land occupation and human toxicity) that respond weakly to supply-side decarbonization, extending their value beyond climate mitigation.
Plastic waste, bauxite residues, and emission-intensive cement production are pressing environmental challenges. While multiple attempts are made, an integrated solution addressing all three, delivering both environmental and economic benefits, remains a major challenge. Here, we develop an integrated approach using bauxite residue (red mud, RM) as a catalytic bridge to upcycle mixed plastic waste (polyethylene [PE], polypropylene [PP], and polystyrene [PS]) into cement additive. During RM-catalyzed pyrolysis at 850°C, in situ reduction of iron oxides generates active Fe0/Fe3C species, yielding 391 mg/gplastic carbon nanotubes (CNTs) while co-producing 26.4 mmol/gplastic H2. Adding just 0.1 wt % CNTs into cement enhances compressive strength by 39.3% and reduces cement usage by 4.8%–5.8%, primarily attributed to pore-filling, enhanced hydration, and interlocking CNT-ettringite (AFt) networks formed from Fe/Al in RM. The process achieves net-negative GHG emissions (−5.3 ∼ −6.8 t/tplastic) and profits around $169.1/tplastic, offering a practical circular solution that transforms waste streams of mixed plastics into low-carbon construction materials.
