Soil temperature regulates microbial metabolism and carbon decomposition processes, creating critical feedbacks to atmospheric CO₂ concentrations under climate change scenarios. This study investigated the temperature sensitivity of soil microbial communities and associated CO₂ fluxes through controlled warming experiments across diverse terrestrial ecosystems. A comprehensive five-year field experiment (2018-2023) was conducted at four sites representing different biomes: temperate deciduous forest (Harvard Forest, MA), boreal coniferous forest (Fairbanks, AK), temperate grassland (Konza Prairie, KS), and Mediterranean shrubland (Santa Barbara, CA). Experimental warming treatments included control (ambient temperature), moderate warming (+2°C), and intensive warming (+4°C) using infrared heating systems and soil heating cables. Soil CO₂ efflux, microbial biomass, enzyme activities, and soil organic carbon fractions were monitored continuously throughout the study period. Results demonstrated significant increases in soil CO₂ emissions following warming treatments, with Q₁₀ values ranging from 1.8 to 3.2 across ecosystems. Moderate warming increased soil respiration by 23-41% initially, but responses diminished over time due to microbial acclimation and substrate depletion. Intensive warming (+4°C) sustained higher CO₂ fluxes (48-67% increase) throughout the study period. Microbial biomass carbon decreased by 15-28% under warming treatments, while specific enzyme activities increased 2-4 fold, indicating metabolic acceleration. Fast-cycling carbon pools showed 35-52% depletion under intensive warming, while slow-cycling pools remained relatively stable. Temperature sensitivity varied significantly among ecosystems, with boreal forests showing highest Q₁₀ values (3.2) and grasslands lowest (1.8). Microbial community composition shifted toward thermophilic species, with bacterial:fungal ratios increasing from 2.1 to 3.8 under intensive warming. Carbon use efficiency decreased from 0.31 to 0.19 with temperature increase, indicating reduced microbial carbon retention. The study reveals complex temporal dynamics in soil carbon-climate feedbacks, with initial strong positive responses followed by partial acclimation, highlighting the importance of long-term experiments for understanding ecosystem responses to climate change.