Carbon storage plays an important role in understanding interactions among climate, ecosystems, and humans; as well as carbon budgets in the biosphere, the atmosphere, and the oceans. Therefore, characterizing global and regional carbon storage more accurately is very necessary. China is an important region for carbon study because of its vast territory with various climate regimes, diverse ecosystems, and long-term human disturbances and land-use history. Carbon storage in ecosystems in China has been extensively investigated in the past two decades. However, different methodologies and various spatial-temporal scales have resulted in discrepancies in the magnitudes and variations of carbon storage, and thus, make the comparison of carbon storage at national and regional scales difficult.

In order to approach a more accurate estimate of carbon storage and a better understanding of global and regional carbon budgets, Professor NI Jian’s group from the State Key Laboratory of Environmental Geochemistry (SKLEG), Institute of Geochemistry, Chinese Academy of Sciences (IGCAS), synthesized the current knowledge on carbon storage in terrestrial ecosystems in China based on available data and publications. The group also analyzed the advantages and disadvantages of different methodologies and available data sources. 

Their study summarizes the carbon storage in terrestrial ecosystems in China in two spatial scales, namely, national and biome levels. According to available estimates, vegetation carbon at China’s national level is 6.1 Pg C to 76.2 Pg C (mean 36.98 Pg C) and soil carbon is 43.6 Pg C to 185.7 Pg C (mean 100.75 Pg C). At the biome level, vegetation and soil carbon storages in forest, grassland and cropland sectors exhibit more significant regional variations. Meanwhile, their results disclose that significant differences in data have existed among studies and such differences are mainly attributed to variations in estimation methods, data availability, and periods.

It is concluded that a complete and accurate carbon accounting in China needs a more comprehensive methodology that combines national inventory, field measurement, eddy covariance technique, remote sensing, and model simulation in a single framework, as well as all available data at different temporal and spatial scales.

The results have been published in a top journal of global change research, Climatic Change, in 2013 (Ni, J. 2013. Carbon storage in Chinese terrestrial ecosystems: approaching a more accurate estimate. Climatic Change 119(3-4): 905-917.)  

(By NI Jian)