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Because China has emerged as the largest greenhouse gas (GHG) emitter in total annual emissions, to accelerate the pace of GHG emission reduction in China is important to the success of global efforts in addressing climate change. Carbon trading is a market mechanism and key instrument in the mitigation of climate change. This paper explores the policy process and development state to date of China׳s carbon-trade market to understand the emergence and development of that market and to understand what barriers are hampering China׳s carbon-trade market development. To achieve this goal, this paper introduces and analyzes China׳s status in the international market, examines the factors driving carbon-market launching by the Chinese government, and traces the development of mandatory carbon-emission trading and voluntary emission trading. It is argued that China׳s carbon-trading market is confronted with challenges such as the absence of a functional carbon-trading market, inaccuracy of the quota allocation, an imperfect trading mechanism, and lagging legislation. At the present stage, shortcomings such as having no real-time carbon price and dominated spot transactions differentiate China׳s trade market substantially from a functional system. A quick market integration of China׳s carbon market appears remote. It is suggested that specific measures be taken to promote the development of the Chinese carbon-trading market. [ABSTRACT FROM AUTHOR]

Alpine wetlands are considered to be very sensitive to future climate warming. Understanding changes in decomposition rates ( Rs) of soil organic matter (SOM) and temperature sensitivity ( Q) in alpine wetlands, under the scenarios of a warming climate and decreasing soil moisture, is important for predicting their carbon (C) budget. Here, we established three sampling transects from wetland edge to meadow in the Zoige alpine wetlands in China, which represented the gradients of decreasing soil moisture. We conducted an incubation experiment (5-25 °C) to explore changes in Q with the degradation process from alpine wetland to alpine meadow. The results showed that temperature significantly influenced Rs in all locations. Rs first increased from site I to site IV and then decreased from site IV to site V. However, Q and activation energy ( E) showed no apparent trends with soil coming from sites along a moisture gradient. Overall, the Q values in the wetland (sites 1.50) were significantly lower than that of the meadow (1.83); similar trends were observed for E. In addition, E exhibited a negative logarithmic relationship with C quality indices in all locations, which suggested that the C quality-temperature hypothesis is applicable to both alpine wetlands and meadows. These findings provide a theoretical foundation for predicting the potential influences of warming climate on soil C turnover and storage in alpine wetlands. [ABSTRACT FROM AUTHOR]

Decomposition of soil organic matter (SOM) is sensitive to vegetation and climate change. Here, we investigated the influence of changes in forest types on the mineralization of soil carbon (C) and nitrogen (N), and their temperature sensitivity (Q10) and coupling relationships by using a laboratory soil incubation experiments. We sampled soils from four forest types, namely, a primary Quercus liaotungensis forest (QL), Larix principis-rupprechtii plantation (LP), Pinus tabulaeformis plantation (PT), and secondary shrub forest (SS) in temperate northern China. The results showed that soil C and N mineralization differed significantly among forest types. Soil C and N mineralization were closely coupled in all plots, and C5N ratios of mineralized SOM ranged from 2.54 to 4.12. Forest type significantly influenced the Q10 values of soil C and Nmineralization. The activation energy (Ea) of soil C and Nmineralization was negatively related to the SOM quality index in all forest types. The reverse relationships suggested that the carbon quality-temperature (CQT) hypothesis was simultaneously applicable to soil C and N mineralization. Our findings show that the coupled relationships of soil C and N mineralization can be affected by vegetation change. [ABSTRACT FROM AUTHOR]