Increased forest coverage will induce more carbon fixation in vegetation than in soil during 2015–2060 in China based on CMIP6

Abstract

As components of terrestrial carbon sinks, vegetation and soil carbon pools are important for offsetting CO2 emissions. However, differences in their carbon sequestration capacities and their responses to global change in the future are poorly understood. This study assessed the changes in vegetation and soil carbon and their ratios and drivers under the SSP126 scenario from 2015 to 2060, using Coupled Model Intercomparison Project phase 6 (CMIP6) simulations in China, a major carbon sink region in global terrestrial ecosystems. The content of vegetation carbon (29±1 PgC) was observed to be lower than that of soil carbon (113±23 PgC), and the ratio of vegetation to soil carbon was the highest in the subtropical-tropical monsoon climatic region (0.55±0.12). Moreover, the total stock of vegetation and soil carbon increased by 10±1 PgC during the study period, and the increase in vegetation carbon was 4.31 times that of soil carbon, because the responses of vegetation carbon stocks to increased forest coverage and atmospheric CO2 were greater than that of soil carbon stocks, especially in the subtropical-tropical and temperate monsoonal climatic regions. However, bare land encroachment on grasslands reduced their increments in the temperate monsoonal and high-cold Tibetan Plateau climatic regions. Furthermore, compared with SSP245 and SSP585 scenarios, vegetation and soil carbon sinks can offset a greater amount of carbon emissions in 2060 under the SSP126 scenario, accounting for 53% of all carbon emissions, offsetting 60%–79% of carbon emissions from China under its policy of increasing forest coverage. The study revealed the important role of afforestation in increasing ecosystem carbon stocks, additionally, grassland conservation and deep reductions in carbon emissions cannot be ignored in the future. This study provides a basis for determining the response of vegetation and soil carbon to environmental factors and the realization of net-zero emissions globally.

Reconstructing Long‐Term Forest Age of China by Combining Forest Inventories, Satellite‐Based Forest Age and Forest Cover Data Sets

“…This makes two assumptions: (a) large area deforestation in China will not occur; (b) the forest cover area will continue to increase at the rate observed over the past 10 years (∼1.58 × 10 4 km 2 yr −1 ). China's forest coverage is expected to reach 30% by 2060 (Zhang et al., 2022). Our results indicate that the mean forest age of China will reach 71.6 years old in 2060 (Figure 11), which will be very useful to estimate the forest carbon sink in China.…”

A Refined Supply‐Demand Framework to Quantify Variability in Ecosystem Services Related to Surface Water in Support of Sustainable Development Goals

“…SSP245 represents a medium radiative forcing pathway (4.5Wm −2 ) and 3°C‐limited warming. SSP585 represents a high unsustainable radiative forcing pathway (8.5Wm −2 ) and 5°C‐limited warming (Cook et al., 2020; IPCC, 2023; Li, Li, et al., 2021; Siabi et al., 2023; Zhang, He, et al., 2022). Precipitation, temperature and solar radiation across three CMIP6 scenarios will generate different potential evapotranspiration and WY.…”

Tracking Land-use Trajectory and Other Potential Drivers to Uncover the Dynamics of Carbon Stocks of Terrestrial Ecosystem in the Songnen Plain

“…Greening (afforestation) shows the difference between human factors and natural factors in terms of vegetation biocarbon; greening brought about by human factors can rapidly form woodlands or grasslands with good vegetation conditions in a short period of time, while natural factors usually require a long-term vegetation succession process. However, the sequestration efficiency of vegetation biocarbon stocks is higher than that of soil organic carbon for both human and natural factors, suggesting that vegetation will have more carbon sequestration than soil [67].…”