退耕还林还草工程(GGP)是中国投资最大、涉及面最广、群众参与程度最高的生态修复项目,也是国土变绿和陆地碳增汇的主要驱动力,然而对其碳增汇潜力及其对碳中和目标的可能贡献仍缺少系统性评估.本文在回溯2000-2020年京津冀地区GGP碳增汇作用基础上,设置由不同气候变化、经济社会、生态规划组合而成的可持续发展、基准、区域竞争3种未来情景,预测双碳目标年(2030年和2060年)GGP的碳增汇潜力及其贡献率.结果表明:①2000-2020年京津冀地区GGP的碳汇增量超过48.03 Tg C,其中面积占比23.9％的退耕还林碳增汇能力达123.7％.②2030年京津冀地区GGP年碳汇增量可达5.33～6.20 Tg C a-1,与2020年相比增加95.8％～127.7％,仅能抵消全地区近0.3％的碳排放总量,但对于抵消县域尺度碳排放量的贡献率可达30％.③2060年GGP年碳汇增量约4.35～4.88 Tg C a-1,与2020年相比增加59.7％～79.3％,能抵消全地区5.1％～7.2％的碳排放总量,且在县域尺度上对碳排放量的抵消可达到8倍.综上所述,需要正确认识生态修复对京津冀地区双碳目标的作用,特别是西北部生态涵养区的县域可将GGP作为实现碳中和的主要路径.
Projecting the carbon sink potential and contribution of Grain for Green Program in the Beijing-Tianjin-Hebei region
The Grain for Green Program(GGP)is the most invested,policy-oriented,wide-embracing,and public-involving ecological restoration project in China,which has become the main driver of national greening and carbon sink increases;however,the large potential of carbon sink increases and their contribution to the program's carbon neutrality goal still lacks systematic estimation.Here,based on backdating of the GGP effect on increasing carbon sinks in the Beijing-Tianjin-Hebei(BTH)region over the past 20 years,three scenarios-sustainable development,benchmark,and regional competition-are combined under different climates,socioeconomies,and eco-planning patterns to forecast the potential for increasing carbon sinks and the contribution of the GGP in the"Double Carbon Target"years(2030 and 2060).Our results showed that:(1)During 2000-2020,the increase in carbon sinks exceeded 48.03 Tg C;among them,the ability of increased carbon sinks in the region to restore croplands to forests(GGP-Forest),which accounted for 23.9％of the total area,reached 123.7％.(2)In 2030,the annual increase in carbon sinks resulting from the GGP in the BTH region will reach 5.33-6.20 Tg C a-1,up by 95.8％-127.7％compared with the year 2020.This can offset～0.3％of the total carbon emissions from this region;however,this contribution can reach 30％at the county scale.(3)In 2060,the annual increase in carbon sinks resulting from the GGP in the BTH region will be about 4.35-4.88 Tg C a-1,up by 59.7％-79.3％compared with 2020 and can offset 5.1％-7.2％of the total carbon emissions from this region;its contribution can reach eightfold at the county scale.In summary,it is essential to correctly quantify the contribution of the Double Carbon Target in the study region resulting from the ecological restoration program,especially in the northwest counties in the ecological conservation area,where the GGP can act as the main method to achieve carbon neutrality.
Grain for Green Programpotential of carbon sink increasesDouble Carbon Targetcontribution rateBeijing-Tianjin-Hebei region
NETL
NSTL
万方数据
