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Net Primary Production in China is on the Rise
Reference
Fang, J., Piao, S., Field, C.B., Pan, Y., Guo, Q., Zhou, L., Peng, C. and Tao, S. 2003. Increasing net primary production in China from 1982 to 1999. Frontiers in Ecology and the Environment 1: 293-297.

What was done
The authors used "a satellite-based carbon cycle model called CASA (Carnegie-Ames-Stanford Approach) (Potter et al., 1993; Field et al., 1995), combined with a number of surface observations within China to explore the trends and spatial patterns of terrestrial NPP [net primary production] in China between 1982 and 1999."

What was learned
China's terrestrial NPP increased by 18.7% over the time period investigated. Referring to this result as "an unexpected aspect of biosphere dynamics," Fang et al. state that this increase "is much greater than would be expected to result from the fertilization effect of elevated CO2, and also greater than expected from climate, based on broad geographic patterns." But is that really so?

What it means
From 1982 to 1999, the atmosphere's CO2 concentration rose by approximately 27.4 ppm. Based on the procedure and reasoning described in our Editorial of 18 Sep 2002, the aerial fertilization effect of this CO2 increase could be expected to have increased the NPP of the conglomerate of forest types found in China by about 7.3%. But this increase is only a part of the total NPP increase we could expect, for Fang et al. note that "much of the trend in NPP appeared to reflect a change towards an earlier growing season," which was driven by the 1.1C increase in temperature they found to have occurred in their region of study between 1982 and 1999.

Following this lead, we learn from the study of White et al. (1999) -- which utilized 88 years of data (1900-1987) that were obtained from 12 different locations within the eastern U.S. deciduous forest that stretches from Charleston, SC (32.8N latitude) to Burlington, VT (44.5N latitude) -- that a 1C increase in mean annual air temperature increases the length of the forest's growing season by approximately five days. In addition, White et al. determined that a one-day extension in growing season length increased the mean forest NPP of the 12 sites they studied by an average of 1.6%. Hence, we could expect an additional NPP increase due to the warming-induced growing season expansion experienced in China from 1982 to 1999 of 1.6%/day x 5 days = 8.0%, which brings the total CO2-induced plus warming-induced increase in NPP to 15.3%.

Last of all, we note there is a well-documented positive synergism between increasing air temperature and CO2 concentration (Idso and Idso, 1994), such that the 1C increase in temperature experienced in China between 1982 and 1999 could easily boost the initial CO2-induced 7.3% NPP enhancement to the 10.7% enhancement that when combined with the 8.0% enhancement caused by the warming-induced increase in growing season length would produce the 18.7% increase in NPP that has been detected in the satellite data.

In view of these observations, the findings of Fang et al. are seen to be right in line with what would be expected to result from the increases in air temperature and atmospheric CO2 concentration that occurred between 1982 and 1999 in China: a dramatically stimulated terrestrial biosphere that is growing ever more productive with each passing year. This is the true observed consequence of the "twin evils" of the radical climate-alarmist movement (rising CO2 and temperature); and it is about as opposite and far removed as one can get from the horror stories this group promulgates, i.e., that the increases in these two factors are greater threats to the well-being of the biosphere, including humanity, than either nuclear warfare or world terrorism.

References
Field, C.B., Randerson, J.T. and Malmstrom, C.M. 1995. Global net primary production: combining ecology and remote sensing. Remote Sensing of the Environment 51: 74-88.

Idso, K.E. and Idso, S.B. 1994. Plant responses to atmospheric CO2 enrichment in the face of environmental constraints: A review of the past 10 years' research. Agricultural and Forest Meteorology 69: 153-203.

Potter, C.S., Randerson, J.T., Field, C.B., et al. 1993. Terrestrial ecosystem production: a process model based on global satellite and surface data. Global Biogeochemical Cycles 7: 811-841.

White, M.A., Running, S.W. and Thornton, P.E. 1999. The impact of growing-season length variability on carbon assimilation and evapotranspiration over 88 years in the eastern US deciduous forest. International Journal of Biometeorology 42: 139-145.


Reviewed 8 September 2004