On 15 March 2021, Chinese President Xi Jinping pointed out that “achieving carbon peak and carbon neutrality is a broad and profound economic and social systemic change” and called for “putting energy and resources conservation in the first place”. Natural resources are the material basis, space carrier and energy source of high-quality development. The source of carbon emissions is resource utilization, and carbon reduction and removal also depend on resources. The improvement of carbon sink capacity is inseparable from natural resources. To achieve the goal of “double carbon”, it is necessary to consolidate the carbon sink capacity of the ecosystem, as well as enhancing its carbon sink increment. Among natural resources, forest carbon sinks, soil carbon sinks and karst carbon sinks have significant emission reduction potential and cost advantages, representing important means to deal with climate change. This paper reviews the relevant research results at home and abroad, summarizes the carbon sink estimation, carbon sink potential, carbon sink influencing factors, ecological compensation mechanism and other aspects, analyzes the path selection of establishing carbon sink green development, and puts forward corresponding policies and suggestions, providing a theoretical reference for the achievement of the carbon neutrality goal in the field of natural resources in China.

Since the Industrial Revolution, the impacts of human activities have changed the global climate system, and climate warming has had rapid and widespread effects on the planet. At present, the world is experiencing a series of natural disasters, such as climate change, environmental pollution, biodiversity loss, and sea level rise, which pose a serious threat to the livability of the Earth. An international consensus has been reached that achieving carbon neutrality is the key to tackling climate change; it is also crucial to building a livable planet. To achieve carbon neutrality, energy is the main aspect, for which technology regarding resources and the environment is essential. In this context, we collected data, performed an in-depth analysis of the basic and structural characteristics of the development of the coal industry and environmental remediation, studied and judged the trends in regional economic development and demand growth, and closely examined the requirements of China’s development strategy, which focuses on the ideas of carbon peak and carbon neutralization in line with local development trends and economic system characteristics. We must build a livable Earth, promote the green and low-carbon transformation of regional energy, promote high-quality economic development, and ensure the safe supply of energy.

Based on the information from an actual petroleum-contaminated site, a one-dimensional soil column was used to examine the vertical transportation diversities of different petroleum components under the influence of water table fluctuations, and the results revealed the following: (1) There were two obvious pollution accumulation zones under the condition of water table fluctuations: (i) The pollution infiltration zone dominated by the residual phase was formed at the leakage position, and (ii) the floating zone dominated by the free phase was formed near the water table. Combined with the viscosity of the organic components, the concentrations of the residual phase were octanoic acid > hexadecane > cyclohexane > toluene. Compared to coarse sand, clay can adsorb more components. (2) Different fluctuation frequencies had a great influence on the migration process of components. The free phase can transfer into the residual phase during the low groundwater table fluctuation. In the case of high-frequency groundwater fluctuations, there were more free phase components that can be carried by the water flow. However, due to the continuous flushing by the water, pollutants were finally spread to the whole underground system. (3) A cost-effectiveness remediation strategy is based on the difference in pollutant transportation. Therefore, the conclusions in this paper are fully applied in the actual contaminated sites. Specifically, the air-sparing (AS) and soil vapor extraction (SVE) devices were installed in the vadose zone to remove volatile substances (such as toluene). The permeable reactive barriers (PRBs) were set in the groundwater fluctuation zone to repair the residual pollutants (alkanes, cyclane, and asphaltenes hydrocarbons) that are continuously converted from the residual phase to the dissolved phase and free phase due to water level fluctuations. Hence, the results of this study provided a specific, targeted, and comprehensive strategy for petroleum pollution treatment.

Soil moisture content continuously alters the types and forms of petroleum organic pollutants in the soil through processes such as dissolution, convection, and dilution, forming complex migration and transformation in a water–air–soil–NAPL system. Field investigations and traditional indoor simulation experiments have difficulty in terms of accurately diagnosing the state of different petroleum pollutants due to the influence of environmental factors and the difficulty of controlling single factors. Batch experiments were conducted to simulate the mobilization and differentiation processes of petroleum pollutants under the influence of soil water content. The results show that (1) the residual content of components is the lowest in coarse sand and the highest in clay, which is mainly affected by soil particles; meanwhile, the residual saturation value of octanoic acid is the largest, and that of toluene is the smallest, as determined in terms of their viscosity and volatility. (2) The infiltration processes of the components are affected by their properties and medium characteristics. Due to its small particle size and strong adsorption, clay has the highest residual saturation of petroleum pollutants (28.8%). This can even be more than twice that of coarse sand (13.3%). For different components, the residual saturations of octanoic acid and toluene are the highest and lowest, respectively (taking fine sand as an example: 25.3% and 13.2%), with a relatively large difference, as determined in terms of viscosity and solubility. (3) As the free phase can migrate freely, it is transformed most rapidly in the pores. The changes in the dissolved phase of each component are relatively small and tend to be gentle. The changes in the residual phase are mainly affected by volatility, viscosity, soil particles, and pore and cosmid content; the degree of change is ordered as follows: toluene > cyclohexane > hexadecane > octanoic acid.

We perceived a trend in the study and practice of petroleum-contaminate sites. Monitored natural attenuation (MNA) can reduce the contaminant concentrations in the soil and groundwater, and it is a method that can remediate the petroleum-contaminated site effectively. MNA is becoming a research focus. This study evaluated MNA using a series of lab-based bench-scale experiments and a large amount of monitoring data from field samplings. Based on the in-site total petroleum hydrocarbon (TPH) results, we used statistical methods, the Mann-Kendall test, and mass fluxes in order to evaluate the MNA of petroleum-contaminated sites in groundwater. The results showed that the TPH concentrations were decreasing, and the plume became smaller. The attenuation rate was from 0.00876 mg/d to 0.10095 mg/d; remediating the petroleum contamination site would cost 1.3 years to 10.6 years. The plume reached a quasi-steady state, and mass flux declined. The most essential process of MNA was biodegradation, and the second was sorption. During the monitoring period, 393 g of TPH was attenuated, including 355 g of TPH gradated by microbes. Biodegradation upstream of the plume was more serious. Iron(Ⅲ) and manganese were the main electron acceptors utilized by microbes during the monitored period. MNA was in progress, and it can be an effective method to remediate the petroleum-contaminated site. Lab-based bench-scale experiments were performed with much monitoring data from the field samplings in order to understand the fate and transport mechanism of the petroleum contamination from the land surface to shallow groundwater according to site conditions.

A quantitative and qualitative assessment using molecular markers derived from compound-specific indices for indicating groundwater impacted by petroleum spills in an oil field was recently undertaken and demonstrated serious contamination, with both high total petroleum hydrocarbons (TPH) (3.68–7.32 mg/L) and hazardous compounds in the groundwater. A petroleum source was identified, and the analysis revealed a decreasing trend of fresh petroleum input, along with groundwater advection and an increasing trend of biodegradation potential at locations farther from the source. This was confirmed via microbial analysis with both biodegrading microorganisms and diversity indices (Shannon, Simpson, and Pielou) and the principal component analysis (PCA) modeling approach, which classified the field samples into three types according to the distribution correlations between different organic compounds. Biodegradation was believed to be the dominant sink of hydrocarbons due to the increasing Pr/C17 and Ph/C18 values with seasonal changes. Raised temperatures activated the microbial degradation process; specifically, low-weight hydrocarbons degraded more rapidly than high-weight hydrocarbons, resulting in the accumulation of an unresolved complex mixture of bioproducts at locations that were farther away. Spatially, the Pr/C17 and Ph/C18 values increased from the upstream to the downstream areas, showing substantial biodegradation. The relationships between the molecular markers and chemical indices were quantified via canonical correlation analysis (CCA) to visually explain the interactive reaction processes. It was also demonstrated that the biodegradation of petroleum organics can be characterized by the consumption of dissolved oxygen and a decreasing Pr/Ph ratio, due to system reduction. These results demonstrate that compound-specific molecular markers, coupled with biochemical parameters, can effectively support a better understanding and effective fingerprinting of the fate and transport of petroleum organic contaminants, thus offering valuable technical support for a cost-effective remediation strategy.