<p>Ocean fronts are critical features that influence marine ecosystems and can affect climate at both regional and global scales. In many regions, fronts enhance vertical mixing and advection, increasing nutrient supply, which can stimulate primary production and modulate air–sea CO₂ fluxes. However, a global perspective on the impacts of changing ocean fronts on primary production and air–sea CO₂ exchange is still lacking. Here using satellite observations (2003–2024) and supplementary reanalysis data at higher latitudes (2003–2024), we identify areas with the richest frontal activity and the fastest-changing frontal properties. We find that 72% of global ocean CO₂ uptake occurs in key frontal areas. Trends in sea surface chlorophyll concentration and ocean CO₂ uptake closely track changes in local frontal activity. Our results indicate that ocean fronts play a central role in regulating the global carbon cycle by influencing the biological component of air–sea CO₂ fluxes.</p>