What was done
The authors analyzed 18 years (January 1982 to December 1999) of climatic data and satellite observations of Normalized Difference Vegetation Index (NDVI) throughout all of China, calculating terrestrial vegetative net primary productivity (NPP) using the revised light-use efficiency model of Zhu et al. (2006) and Zhu et al. (2007).

What was learned
Zhu et al. say their results indicate that "climatic changes in China have eased some critical climatic constraints on plant growth." They note, for example, that "water availability most strongly limits vegetation growth over 28% of the whole country surface, whereas temperature limits growth over 43% and radiation over 29%," but they report that "from 1982 to 1999, modeled NPP increased by 1.42% per year in water-limited regions of Northwest China, 1.46% per year in temperature-limited regions of Northeast China and Tibet Plateau, and 0.99% per year in radiation-limited regions of South China and East China." Summed over the entire 18-year period, total Chinese terrestrial vegetation NPP increased by 24.2%. Last of all, they report that "interannual variations of NPP in Chinese terrestrial vegetation are positively correlated with global increases in atmospheric CO2 growth rate, indicating that NPP in Chinese terrestrial vegetation will increase with the global increases in atmospheric CO2 growth rate."

What it means
Green is good! And China has grown ever greener as the atmosphere's temperature and CO2 concentration have risen to heights that climate alarmists typically describe as being unprecedented over thousands to millions of years, respectively.

References
Zhu, W.Q., Pan, Y.Z., He, H., et al. 2006. Simulation of maximum light use efficiency for some typical vegetation types in China. Chinese Science Bulletin 51: 457-463.

Zhu, W.Q., Pan, Y.Z. and Zhang, J.S. 2007. Estimation of net primary productivity of Chinese terrestrial vegetation based on remote sensing. Journal of Plant Ecology 31: 413-424.