Background
In introducing their study, the authors write that "both theoretical arguments and models suggest that net high-latitude precipitation increases in proportion to increases in mean hemispheric temperature (Houghton et al., 2001; Rahmstorf and Ganopolski, 1999; Bruce et al., 2002)," and that in these scenarios "under global warming, mainly in the middle and west regions of northwest China, precipitation increases significantly," so that "some researchers [have] even advanced the issue of [a] climatic shift from warm-dry to warm-wet in northwest China (Shi, 2003)," with the ultimate expectation being that total river discharge within the region would significantly increase in response to global warming.

What was done
As a test of global climate model predictions, Cao et al. analyzed annual discharge data for the five large rivers of the Qinghai-Tibet Plateau over the period 1956-2000, using the Mann-Kendall nonparametric trend test.

What was learned
The researchers report that over the period of their study, "river discharges in the Qinghai-Tibet Plateau, in general, have no obvious change with the increase of the Northern Hemisphere surface air temperature."

What it means
Because they could detect, in their words, "no increase in the stream discharge in the Qinghai-Tibet Plateau with global warming," Cao et al. conclude that their real-world findings are not "in accordance with the anticipated ideas" that led them to conduct their study. Indeed, the maintenance of the status quo in this and so many other studies argues strongly against either the claimed consequences of global warming (tending towards catastrophic) or the claimed degree of global warming (already unprecedented) or both of these standard climate-alarmist claims.

References
Bruce, J.P., Holmes, R.M., McClelland, J.W. et al. 2002. Increasing river discharge to the Arctic Ocean. Science 298: 2171-2173.

Houghton, J.T., Ding, Y., Griggs, D.J., Eds. Climate Change 2001: The Scientific Basis. Cambridge University Press, Cambridge.

Rahmstorf, S. and Ganopolski, A. 1999. Long-term global warming scenarios computed with an efficient coupled climate model. Climatic Change 43: 353-367.

Shi, Y. 2003. An Assessment of the Issues of Climatic Shift from Warm-Dry to Warm-Wet in Northwest China. Meteorological Press, Beijing.