Carbon Dioxide and Earth's Future Pursuing the ... - Magazooms

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Most recently, Stephens et al. (2010) employed “new and definitive measures of precipitation
frequency provided by CloudSat [e.g., Haynes et al., 2009]” to assess the realism of global
model precipitation via an analysis that employed five different computational techniques
representing “state-of-the-art weather prediction models, state-of-the-art climate models, and
the emerging high-resolution global cloud ‘resolving’ models.” The results of this exercise
indicated that “the character of liquid precipitation (defined as a combination of accumulation,
frequency, and intensity) over the global oceans is significantly different from the character of
liquid precipitation produced by global weather and climate models,” and that “the differences
between observed and modeled precipitation are larger than can be explained by observational
retrieval errors or by the inherent sampling differences between observations and models.”
More specifically, Stephens et al. reported that for precipitation over the global ocean as a
whole, “the mean model intensity lies between 1.3 and 1.9 times less than the averaged
observations,” while occurrences “are approximately twice the frequency of observations.”
They also found that the models “produce too much precipitation over the tropical oceans” and
“too little mid-latitude precipitation.” And they indicate that the large model errors “are not
merely a consequence of inadequate upscaling of observations but indicative of a systemic
problem of models more generally.”
In concluding their study, the nine US, UK and Australian researchers say their results imply that
state-of-the-art weather and climate models have “little skill in precipitation calculated at
individual grid points,” and that “applications involving downscaling of grid point precipitation
to yet even finer-scale resolution has little foundation and relevance to the real earth system,”
which is not too encouraging a result, considering it is the “real earth system” in which we live
and for which we have great concern. Therefore, given these findings, as well as the many
others previously cited, it is difficult to conceive how today’s state-of-the-art computer models
can be claimed to produce reliable flood and drought forecasts decades and centuries into the
future.
Fortunately, there exists an alternative means by which the claim that global warming will
result in more frequent and severe floods and droughts can be evaluated. Since climate
alarmists contend the earth has already experienced a warming that has been unprecedented
over the past millennium or more, we can assess the validity of their claims about the future of
floods and droughts by examining to what extent the planet’s emergence from the global chill
of the Little Ice Age has -- or has not -- impacted the frequency and magnitude of these two
extreme and often-deadly forces of nature. Or for records that are long enough, we can
compare the characteristics of these phenomena as they were expressed during the cold of the
Little Ice Age and the heat of the prior Medieval Warm Period. And as we do so, we find that
there does not appear to have been any warming-driven increase in floods or droughts, as
demonstrated by the papers reviewed in the following two subsections of this document.
With respect to prior observed effects of warming on floods, we focus first on Europe, where
Nesje et al. (2001) analyzed a sediment core from a lake in southern Norway, attempting to
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