Difficulties in Reducing Atmospheric CO₂ Concentrations during the Modern Warm Period

According to the IPCC, when anthropogenic CO₂ emissions increase, the atmospheric CO₂ concentration increases, and the temperature increases due to the greenhouse effect of CO₂. In the mechanism derived in our recent papers, the rise in temperature during the modern warm period increases CO₂ emissions due to an increase in soil respiration (Rs control process). The CO₂ emitted due to an increase in temperature can be considered thermally induced CO₂. Therefore, although there is a correlation between temperature and CO₂ concentration, there is a temperature-leading time lag due to the Rs control process. In this work, we analyzed the relationships between temperature changes and CO₂ concentration changes in detail. As a result, we found that even if anthropogenic CO₂ decreases, it is difficult to reduce the atmospheric CO₂ concentration because of the large Rs control process during the modern warm period. One of the main reasons is that the Rs control process in midlatitude forests is significantly affected by temperature changes, which also means that the increase in anthropogenic CO₂ since the Industrial Revolution has had only a small effect on the change in global CO₂ concentrations.