It is thought that the CO2 emissions from coal-fired power plants contribute greatly to the total anthropogenic CO2 emissions. Ammonia solvent can be used to absorb the CO2, called ammonia scrubbing. However, as has been pointed out, the production of ammonia would emit CO2; therefore, the effectiveness of ammonia scrubbing is doubted. The paper focuses on the problem. Two systems are defined in the paper. System I is CO2 absorption by ammonia scrubbing, and system II is industrial production of ammonium bicarbonate. The total CO2 emissions of the two systems are calculated by means of life cycle assessment. The paper shows that the total CO2 emissions of ammonia scrubbing are less than that of the industrial production of fertilizer ammonium bicarbonate. It can be concluded that ammonia scrubbing is an effective way to reduce the anthropogenic CO2 emissions.