Background <p>Cactus pear (Opuntia ficus-indica) is vital for food security, income, and ecosystem stability in arid and semi-arid regions. In Tigray, it covers 379,338 ha (7.4% of the region), supporting soil conservation, biodiversity, and carbon sequestration. However, infestation by Dactylopius coccus has destroyed over 96,000 ha, intensifying environmental degradation and climate vulnerability, particularly following disruptions linked to the Tigray War. This study assesses the ecological and socio-economic impacts of D. coccus infestation on cactus pear production systems and dryland ecosystems in Tigray, Northern Ethiopia, with emphasis on biomass loss, ecosystem service degradation, and livelihood implications.</p> Methods <p>A systematic review following PRISMA guidelines was conducted, integrating data from 59 peer-reviewed studies and primary stakeholder information. Descriptive and comparative analyses were applied to estimate biomass loss, production decline, and economic impacts.</p> Results <p>Infestation has caused significant reductions in cactus pear biomass, weakening carbon sequestration capacity and accelerating land degradation. Annual fruit production losses are estimated at 84,985 ± 43,699 tons, with substantial effects on household food security. The combined economic loss from reduced production and ecosystem services is approximately USD 1.08 billion annually. Key contributing factors include weak quarantine enforcement, limited biological control measures, and poor institutional coordination.</p> Conclusions <p>The invasion of D. coccus poses severe ecological and socio-economic risks. Immediate implementation of integrated pest management, restoration using resilient cactus varieties, and strengthened institutional and community-based responses are essential. These measures are critical to enhancing climate resilience and sustaining livelihoods in dryland ecosystems.</p>