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To cope with global warming, China has promulgated Enhanced actions on climate change : China ’ s intended nationally determined contributions and will start the national carbon emissions trading market in 2017. Carbon emissions are distributed by the form of free quota and paid quota. However, few literatures have focused on how the economy and the environment would be changed by the change of free quota ratio. This paper establishes the 10 scenarios of different free quota ratio of carbon emissions rights and uses a dynamic, recursive computable general equilibrium (CGE) model to simulate the carbon emissions trading market, to explore the relationship between free quota ratio and carbon trading price, and the impact of carbon trading scheme (ETS) on China’s economy and environment. The results show that free quota ratio will not have a direct impact on gross domestic product (GDP) and other economic and environment indicators but carbon trading prices. The prices and the rate of free payment in the current pilot cities in China are still relatively conservative. It is possible to reach emission peak, 8.21 billion ton, in 2025 and accumulative CO 2 reduction from 2017 to 2030 is 20.02 billion tons, or 59.60% of 2010 world’s total CO 2 emission. Cement, minerals, electricity and nonferrous metals under ETS will suffer great losses, so subsidy should be considered. Finally, we suggested that China should reduce the total carbon rights to increase the carbon price in 2017, and gradually reducing the proportion of free quota, from 90% in 2017 to 50% or less in 2030, by which the peak year of CO 2 emission can meet in 2025. We also suggest that ETS is an effective strategy for CO 2 reduction and the ratio should be gradually reduced in ETS to prevent violent fluctuation of carbon price in China. [ABSTRACT FROM AUTHOR]

Abstract: The Continental Scientific Drilling Project at the Cretaceous-age Songliao Basin is a drilling initiative under the framework of the International Continental Scientific Drilling Program, to recover a nearly complete Cretaceous terrestrial sedimentary record in the Songliao Basin, northeastern China. The recovered cores will provide unique opportunities for the geosciences community to advance the understanding of climate change in the Cretaceous greenhouse world, and provide a documentation of geological events relevant to the carbon cycle during this time period. This drilling project will address significant geological questions, such as the identification of important stratigraphic boundaries and the marine-terrestrial correlations of stratigraphy, the reasons for the biotic response to the terrestrial environmental changes, the terrestrial response to the Cretaceous oceanic anoxic events, the formation of terrestrial petroleum source rocks, and the mechanisms for the Cretaceous magnetic Normal Superchron (CNS). In the first stage of this drilling project, the SKI drilling, rock cores of 2485.89m in total length were recovered and the recovery ratio reached 96.46%. A series of drilling and coring technologies including regular, confined, directional, and sealed coring, were utilized to ensure a higher recovery ratio for the core, and will be described at the end of this paper. Well loggings were conducted right after coring. Core handling and storage were arranged in such a way that the scientific research was conducted on half of each core, whereas the other half of each core was preserved for long-term storage. The upcoming second stage, the SKII drilling, will combine with data from the existing SKI to provide complete high-resolution climate records of the terrestrial environment for the whole Cretaceous time period. [Copyright &y& Elsevier]

Summary: Wetlands are important dissolved organic carbon (DOC) reservoirs, and principal sources of DOC to the fluvial environment, constituting a significant linkage between land and ocean in the context of global carbon cycle. The Sanjiang Plain, a floodplain in Northeastern China that encompasses numerous natural freshwater wetlands, has been experiencing extensive building of drainage ditches and thus elevated degradation of wetlands. This paper investigated DOC, dissolved inorganic carbon (DIC), and dissolved total carbon (DTC) in soil, the surface ponding and rivers from natural wetlands and the degraded wetland, and also in an artificial drainage ditch in the Sanjiang Plain during the growing season (May to October) of 2009. Seasonal averaged DOC concentrations were greater in soil and the surface ponding of the degraded riparian wetland than those originating from the natural riparian wetlands (i.e. Bielahong, Yalv and Nongjiang riparian wetlands). Seasonal averaged DIC concentrations in the surface ponding of the degraded wetland increased by 1.76, 0.59 and 2.05 times, compared to those in the Bielahong, Yalv and Nongjiang riparian wetlands, respectively. Similar to dissolved carbon dynamics in the field sites, the seasonal averaged DOC concentration in the degraded marshy river showed higher value (10.36±1.99mg/L), compared to those in the pristine marshy rivers. Seasonal DIC concentrations followed a trend as the degraded marshy river (15.09±2.43mg/L) – the artificial ditch (12.52±1.61mg/L) – pristine marshy rivers on average (8.53±0.96mg/L). Seasonal mean DTC concentration in the artificial ditch showed higher values than that in the natural marshy rivers, while seasonal mean DTC concentration in the degraded marshy river was greater than that in the artificial ditch. Further, seasonal DOC and DIC dynamics were similar in the artificial ditch and the degraded marshy river. These qualitative changes in the dissolved carbon dynamics in our study might have important implications that the impact of building of artificial ditches on dissolved carbon of waters more fully reflected in increases of dissolved carbon resulting from wetland degradation rather than increases in the artificial ditch itself. [Copyright &y& Elsevier]

Abstract: Water level and chemistry of Lake Qinghai are sensitive to climate changes and are important for paleoclimatic implications. An accurate understanding of hydrological and chemical budgets is crucial for quantifying geochemical proxies and carbon cycle. Published results of water budget are firstly reviewed in this paper. Chemical budget and residence time of major dissolved constituents in the lake are estimated using reliable water budget and newly obtained data for seasonal water chemistry. The results indicate that carbonate weathering is the most important riverine process, resulting in dominance of Ca2+ and DIC for river waters and groundwater. Groundwater contribution to major dissolved constituents is relatively small (4.2 ± 0.5%). Wet atmospheric deposition contributes annually 7.4–44.0% soluble flux to the lake, resulting from eolian dust throughout the seasons. Estimates of chemical budget further suggest that (1) the Buha-type water dominates the chemical components of the lake water, (2) Na+, Cl−, Mg2+, and K+ in lake water are enriched owing to their conservative behaviors, and (3) precipitation of authigenic carbonates (low-Mg calcite, aragonite, and dolomite) transits quickly dissolved Ca2+ into the bottom sediments of the lake, resulting in very low Ca2+ in the lake water. Therefore, authigenic carbonates in the sediments hold potential information on the relative contribution of different solute inputs to the lake and the lake chemistry in the past. [Copyright &y& Elsevier]

• China's water use efficiency showed an increasing trend from 2001 to 2017. • The water use efficiency of forest land is higher than that of low vegetation. • Human activities have a greater contribution to the increase in water use efficiency. • China has more areas with positive correlation between water use efficiency and meteorology. In the context of increasing global carbon emissions, and the relative shortage of water resources, research on the relationships between climate change, human activities and the carbon–water coupling response of China's ecosystems is crucial. Water use efficiency (WUE) is an important indicator reflecting the coupling of ecosystem carbon and water cycles. Based on trend analysis, correlation analysis and multiple regression residual analysis, this paper analyzes the spatiotemporal distributions, change trends, correlations with meteorological factors, changes in different vegetation coverage types, and relative contributions of the main driving factors of China's vegetation WUE from 2001 to 2017. The results show the following: (1) For the past 17 years, the multiyear average value of vegetation WUE in China is 1.08 g C m - 2 mm - 1 , the average annual growth rate is 0.003 g C m - 2 mm - 1 a - 1 . The area with increasing trend of WUE accounts for 59.09% of the total area. (2) The seasonal WUE is highest in autumn, followed by summer, spring and winter. (3) The areas in which vegetation WUE is positively correlated with temperature and precipitation account for approximately 50.21% and 66.16% of the total area, respectively. (4) In terms of the relative annual average value of the WUE, the different vegetation cover types, in descending order, are mixed forests > needleleaf forests > broadleaf forests > shrublands > grasslands > croplands > wetlands > barren lands. (5) Human activities and climate change contributed 66.75% and 33.25%, respectively, to the increase in vegetation WUE in China in the past 17 years. The research results have important scientific significance for clarifying the impacts of climate change and human activities on the carbon–water cycle of the terrestrial ecosystems of China and assessing regional differences in the potential of terrestrial ecosystems to increase carbon sinks. [ABSTRACT FROM AUTHOR]

• Reviews on tectonics and paleoenvironment of the Junggar Basin are present. • An updated chronostratigraphic framework is provided for Permian Junggar Basin. • Dry climate and evaporative environment prevailed during deposition of source rocks. • Stable salinity stratification and limited dilution promoted organic matter burial. • Organic carbon burial in lakes may act as a significant carbon sink in Permian. The Junggar Basin in northwestern China is a typical "walled" sedimentary basin that has a prolonged basin evolution history from the Paleozoic to Cenozoic and is rich in petroleum resources. Permian strata reach thousands of meters in thickness and have been intensively studied for their record of regional tectonics and paleoenvironments. They have also been exploited for oil and gas for the past several decades. In this paper, we summarize perspectives on tectonic evolution, stratigraphic framework, sedimentary environments, and the paleoclimate of the Permian Junggar Basin and the adjacent Turpan Basin. Further, we discuss the mechanism and consequences of massive organic carbon burial. Based on a compilation of published radiometric dating datasets, an updated chronostratigraphic framework was proposed for the Junggar Basin. This framework constrains the ages of two main petroleum source intervals, the Fengcheng Formation and the Lucaogou and equivalent formations, as Early Permian and Middle Permian, respectively. Although a global warming and drying trend was present throughout the Permian Period, the regional climate over the Junggar Basin was drier in Early Permian and more humid in the Middle-Late Permian with short-term climatic fluctuations. During the deposition of the two petroleum source intervals, dry and temperate climate prevailed and evaporative lacustrine environment dominated. Organic matter enrichment was promoted by stable salinity stratification and limited dilution by inorganic sediments, leading to one of the richest lacustrine source rock deposits in the world. The average organic carbon burial rates were 11.2 gC/m2/yr for the Lucaogou Formation and 3.5 gC/m2/yr for the Fengcheng Formation, lower than the average organic carbon burial rate in modern lakes. However, considering the large areas of global tectonic lakes in the Permian Period, organic carbon burial in lacustrine environments could act as a significant carbon sink and impact the global carbon cycle and climate evolution. [ABSTRACT FROM AUTHOR]

Much of our existing knowledge of Middle Jurassic paleoclimate is based on well-dated marine isotopic records that show fluctuations between warm (greenhouse effected) and cool climates. In contrast, much less is known from contemporaneous terrestrial deposits that are often difficult to correlate stratigraphically with marine successions, and are typically considered as showing regional rather than global signals. In this paper we show that the carbon-isotopic, petrological and floral record through 20 m thick coals in the Northern Qaidam Basin (NW, China) represents a relatively comprehensive northern hemisphere Bajocian (Middle Jurassic) record for terrestrial climatic change. δ13C coal values for 88 samples from the Yuqia area in Northern Qaidam Basin range from–25.3‰ to –22.5‰, indicating that C3 plants were the main coal-forming vegetation in the region during the Middle Jurassic. This isotopic variation follows fluctuations in the composition of ferns and gymnosperms, where higher ratios correspond to more negative δ13C values. The similar carbon isotope values of gymnosperms and coal from the Yuqia area indicate that the coal comprises a high proportion of organic material derived from gymnosperm taxa, which is consistent with the very high abundance of diterpenoids in coal and especially pimarane and abietane that are produced primarily by gymnosperms. Results from the coal matrix provide an opportunity to record paleoclimate changes, showing several striking and regular coal-forming cycles with distinct long- and short-term variations. Trends of δ13C coal values changes coupled with the evolution of coal-forming plants may record a gradual increase in paleo-CO 2 (p CO 2) concentration, water-table level changes and the decrease in abundance of Classopollis conifer pollen through Bajocian. This result is in accordance with the published marine carbonate records for this time, with correlation enabled through matching carbon isotope curves from the terrestrial succession at Yuqia and marine records. The similarity of the terrestrial and marine geochemical and floral record is an indication that the observed paleoclimate signal is a global phenomenon. Furthermore, the high-frequency fluctuation of δ13C coal values, along with the coal petrologic variations may record short-term changes of environmental factors (e.g. temperature or humidity/precipitation), especially during intervals when palaeobotanical composition has not fluctuated intensely. • Paleoclimate trends evaluated from terrestrial Northern Qaidam Basin, NW China • Carbon-isotope, petrological and floral record of Bajocian age Yuqia coals revealed • Isotope value distribution indicate coals largely derived from gymnosperm plants • Variations in long- and short- peat deposition cycles record paleoclimate trends • Similarity of marine geochemical and terrestrial record supports global signal [ABSTRACT FROM AUTHOR]