Ammonia is a key component in clean energy, agriculture, and chemical industries. It is considered a "carbon-free fuel" due to its composition of nitrogen and hydrogen. However, the production of ammonia currently relies on fossil fuels, leading to significant carbon emissions. The Haber–Bosch process, the primary method for ammonia production, generates over 400 million metric tons of CO2 equivalent per year. Ammonia produced from fossil fuels is classified as "brown" or "grey," with emissions intensities ranging from 1.6 to 3.2 tCO2/tNH3. To reduce emissions, carbon capture and storage/utilization technologies are being explored, resulting in "blue" and "turquoise" ammonia, with emission intensities as low as 0.1-0.2 tCO2/tNH3. Green ammonia, produced using renewable energy, is the most sustainable option, with the potential to achieve zero emissions. However, the feasibility of green ammonia depends on the carbon intensity of the electricity grid, which needs to be reduced significantly. Achieving net-zero emissions requires moving beyond brown and grey ammonia production, but the cost of ammonia must not increase substantially. Carbon capture is a viable intermediate step to reduce emissions. Life cycle assessments are essential for evaluating indirect emissions and resource consumption. The future of ammonia production lies in sustainable methods that align with global climate goals.Ammonia is a key component in clean energy, agriculture, and chemical industries. It is considered a "carbon-free fuel" due to its composition of nitrogen and hydrogen. However, the production of ammonia currently relies on fossil fuels, leading to significant carbon emissions. The Haber–Bosch process, the primary method for ammonia production, generates over 400 million metric tons of CO2 equivalent per year. Ammonia produced from fossil fuels is classified as "brown" or "grey," with emissions intensities ranging from 1.6 to 3.2 tCO2/tNH3. To reduce emissions, carbon capture and storage/utilization technologies are being explored, resulting in "blue" and "turquoise" ammonia, with emission intensities as low as 0.1-0.2 tCO2/tNH3. Green ammonia, produced using renewable energy, is the most sustainable option, with the potential to achieve zero emissions. However, the feasibility of green ammonia depends on the carbon intensity of the electricity grid, which needs to be reduced significantly. Achieving net-zero emissions requires moving beyond brown and grey ammonia production, but the cost of ammonia must not increase substantially. Carbon capture is a viable intermediate step to reduce emissions. Life cycle assessments are essential for evaluating indirect emissions and resource consumption. The future of ammonia production lies in sustainable methods that align with global climate goals.