In the activities for sinks, increase in the amount of sinks for carbon dioxide brought by tree planting and so on after 1990 is converted and added on the emissions reduction of greenhouse gases.
吸収源活動とは、1990年以降の植林などで二酸化炭素の吸収源が増加した分を、温室効果ガス排出量削減に換算し算入するもの。