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On the Bright Side: The Stability of Glaciers in the Astore Basin of Northwestern Himalaya
By Craig D. Idso of Cato.
"Glaciers have long been viewed as vulnerable to CO2-induced
global warming, as many have experienced declines in thickness and/or
extent over the past century. However, there remains much to be learned
about this topic and how glaciers may respond to climate change in the
future, as evidenced by the recent work of Farhan et al. (2015).
Introducing the rationale for their study, the team of five
researchers write that it is “difficult to develop a clear understanding
of climate-change impacts in the Hindukush–Karakoram–Himalaya region”
of the Tibetan Plateau because of “substantial variability of glacier
changes within the region (Fujita and Nuimura 2011), uncertainties
related to the contribution of glaciers to runoff (Immerzeel et al. 2011), variable retreat rates (Kumar et al. 2008) and strong spatial variations in glacier behavior related to topography and climate (Scherler et al. 2011).” They also note that “uncertainties in projections of glacier changes (Cogley 2011; Lutz et al. 2012), controversial and erroneous reports stated by IPCC (2007) and revealed by Cogley et al. (2010), lack of knowledge, paucity of long term records (Kaser et al. 2006), unsuitable or uncertain data and methods, failure to publish existing data (Barnett et al.
2005), very limited mass balance records particularly in the Upper
Indus River Basin (UIB) (Bhutiyani 1999), and even excessive
classification and secrecy regarding fundamental hydrological data
collectively make these problems much worse.”
Against this backdrop, the five scientists engaged in a new effort to
reduce these uncertainties by investigating the impacts of climate
change on this glaciated region. In doing so, they focused on the Astore
Basin, a high-altitude 4,000 km2 sub-catchment of the Upper
Indus River Basin located in the northwestern Himalayan region of
Pakistan, analyzing the relationship between various meteorological,
hydrological and satellite remote sensing data sets over the past four
decades.
Among the many findings of their study, Farhan et al. report
that trend analysis of the mean monthly snow cover area revealed “no
significant depletion trends” over the period 2003–2010, which was
“mainly because of the fact that there was also no trend in the summer
mean temperature during that period.” In addition, they write that
statistical analyses reveal the annual stream flow fluctuations in the
Astore River over the period 1980–2010 were “predominantly influenced by
variations in precipitation rather than the alteration in catchment
temperatures; consequently, the stream flow fluctuations were not
governed by enhanced glacier ablation and retreat.”
With respect to glacier change, Farhan et al. note that of
the 98 glaciers in this region covering an area greater than one square
kilometer, temporal image analysis for the period 1973-2013 showed that
28 glaciers experienced minor increases, 45 slightly decreased, and the
remaining 25 appeared to be in a stable state. Not surprisingly,
therefore, the overall total glacier area experienced a statistically
insignificant decrease of 0.3 percent over the four-decade period, which
the authors describe as a minor change, within the range of data
accuracy and which suggests “quite stable conditions of Astore basin
glaciers.” What is more, laser altimetry data of glacier thickness changes over the period 2003-2008 “also revealed stability or even a slightly growing trend.”
In summing up their findings, Farhan et al. state that the
observed stability of Astore basin glaciers represents “a different
response to global warming” in which “summer temperature reductions and
positive trends in winter precipitation imply reduced ablation and
increased accumulation … which may lead to balanced and/or positive
glacier ice mass balance … and may explain one of the reasons for their
relative insensitivity to warming.”
Whatever the case may be, one thing is certain—four decades of data
reveal they are not doing what typical global warming theory would
suggest!"
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