Decarbonizing operational emissions in urban neighborhoods with the integration of rooftop photovoltaics and green infrastructure under current and future climate conditions

• Zero-emission EU neighborhoods are feasible by integrating rooftop PVs, NBS, and decarbonized grids. • Carbon neutrality is reached by 2030 in Mediterranean and 2038 in semi-continental climate neighborhoods. • Battery storage boosts rooftop PV self-sufficiency by 17.6%–55.1% in Mediterranean climate neighborhoods. • Tree planting sequesters 0.87 kg CO₂/m² of neighborhood area annually. • PV façades and storage systems are essential for energy neutrality in semi-continental climates. Since the time to achieve the sustainable urban transformation to carbon neutrality and mitigate climate change is limited, rapid and deep actions are needed in a feasible pathway based on existing, scalable, and adaptable technological and natural solutions to be deployed within this decade. In this work, we explore, for the first time to the best of our knowledge, the feasibility of achieving carbon neutrality at representative building blocks of two neighborhoods at different climatic conditions and local climate zones in Europe by combining the already available cost-effective resources of greenery as trees, on-site clean electricity generation with well-developed photovoltaics and grid decarbonization with the current transition rate. Using a robust methodological framework, the analysis integrates 3D urban modeling, radiance-based solar analysis, building energy simulations, and PV/Battery Energy Storage Systems design. Metrics such as self-sufficiency (Ss), self-consumption (Sc), and net energy and carbon balances were evaluated under current and future (SSP1-2.6) climate scenarios. Results indicate that rooftop PV systems coupled with BESS improve Ss to 55.1% in the Ioannina neighborhood and 16.2% in the corresponding Prague, requiring expanded PV facade systems. Integrating nature-based solutions (NBS) contributes to carbon sequestration (21.6 tons/year in Ioannina; 43.2 tons/year in Prague) and enhances urban cooling while mitigating rising energy demands driven by climate change. Carbon neutrality is projected by 2030 in Ioannina and by 2038 in Prague, highlighting the potential of PV and NBS integration as scalable strategies for decarbonizing urban neighborhoods and providing actionable insights for stakeholders in city planning and energy sustainability. Therefore, the clear unlocking of combined effects of contextual relevance can rapidly scale up the reduction of carbon emissions and mitigate climate change.