NC Media Watch

A quest for reason and accuracy in letters to the editor, guest editorials and other issues of interest to the citizens of Western Nevada County.

Wednesday, September 14, 2005

Global Warming Update: Canadian river flow declines 10% in four-decades

Global warming climate models predict an increase flow in northern rivers. Global Warming advocates now claim a 100 year of global warming, with a significant increase in the last 50 years. Then tell me why is it that scientists cannot find the increased flow in northern rivers?
The results of this study [Déry, S.J. and Wood, E.F. 2005. “Decreasing river discharge in northern Canada.” Geophysical Research Letters] indicate there is nothing unusual about the four-decade trends in northern Canada river discharge rates, which is exactly the point: there is nothing in these trends that would suggest a fingerprint of global warming. If anything, the results of this study argue against the worrisome climate-alarmist notion, for state-of-the-art climate models predict global warming will enhance river discharge rates due to an enhanced hydrologic cycle. The trends observed here, however, are just the opposite; and it is clear that they are merely the products of natural variations in various natural phenomena.
Full report here in CO2 Science.

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Blogger Frederic Christie said...

Russ, by now you should have actually learned a bit about global warming: that sometimes warming pressures can actually make coolants or snow because it can be too cold to snow. Here's the answer to your question, after literally 10 seconds of Googling:

"In general, the patterns found are consistent with those identified for precipitation: Runoff tends to increase where precipitation has increased and decrease where it has fallen over the past few years. Flows have increased in recent years in many parts of the United States, for example, with the greatest increases in low flows (Lins and Slack, 1999). Variations in flow from year to year have been found to be much more strongly related to precipitation changes than to temperature changes (e.g., Krasovskaia, 1995; Risbey and Entekhabi, 1996). There are some more subtle patterns, however. In large parts of eastern Europe, European Russia, central Canada (Westmacott and Burn, 1997), and California (Dettinger and Cayan, 1995), a major—and unprecedented—shift in streamflow from spring to winter has been associated not only with a change in precipitation totals but more particularly with a rise in temperature: Precipitation has fallen as rain, rather than snow, and therefore has reached rivers more rapidly than before. In cold regions, such as northern Siberia and northern Canada, a recent increase in temperature has had little effect on flow timing because precipitation continues to fall as snow (Shiklomanov, 1994; Shiklomanov et al., 2000)."

To repeat: A recent increase on temperature has not changed flow timing because precipitation increases are seen in snow, not river flow.

Wed Sep 14, 10:12:00 PM PDT  
Blogger Frederic Christie said...

And, Russ, since you declare that you believe that the globe has warmed thanks to natural influences, you're now busily contradicting yourself. Either there's something disconnecting global climate change, anthropogenic or otherwise, from Canadian river flow (making your post irrelevant) or there isn't and your own claim about global warming isn't true.

Fri Sep 16, 04:48:00 PM PDT  

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