Carbon neutrality is a state achieved when anthropogenic carbon dioxide emissions are balanced globally by anthropogenic removals over a specified period, resulting in a net-zero aggregate contribution to atmospheric carbon concentration from CO2. As an academic concept and research field, it systematically investigates the complex systems and processes necessary to attain and sustain this equilibrium. This includes the rigorous quantification and analysis of emission sources and natural or technological sinks, the development and assessment of mitigation and negative emissions technologies, the design and evaluation of policy instruments and economic mechanisms, and the development of robust monitoring, reporting, and verification frameworks. Key characteristics involve defining the scope of emissions and removals (e.g., specific sectors, geographical boundaries, or global total), establishing baseline periods, and relying on a combination of emissions reduction and deliberate removal activities. Its significance lies in serving as a critical target and framework for global efforts to mitigate climate change and transition towards sustainable socio-economic systems.