Volume 17, Number 30: 23 July 2014
More frequent and more devastating floods are both (1) predicted for the future and (2) claimed to already be occurring by a host of climate alarmists, as a result of climate change that they claim is induced by anthropogenic CO2 emissions. But are these claims correct?
In a massive review of the subject conducted by a team of seventeen researchers hailing from eleven different countries, i.e., Kundzewicz et al. (2013), we learn the following: (1) "no gauge-based evidence has been found for a climate-driven, globally widespread change in the magnitude/frequency of floods during the last decades," (2) "there is low confidence in projections of changes in fluvial floods, due to limited evidence and because the causes of regional changes are complex," (3) "considerable uncertainty remains in the projections of changes in flood magnitude and frequency," (4) increases in global flood disaster losses reported over the last few decades "may be attributed to improvements in reporting, population increase and urbanization in flood-prone areas, increase of property value and degraded awareness about natural risks (due to less natural lifestyle)," (5) "the linkages between enhanced greenhouse forcing and flood phenomena are highly complex and, up to the present, it has not been possible to describe the connections well, either by empirical analysis or by the use of models," and (6) "the problem of flood losses is mostly about what we do on or to the landscape," which they say "will be the case for decades to come."
In closing, Kundzewicz et al. write that "the climate change issue is very important to flooding, but we have low confidence about the science," adding that "work towards improvements in GCMs [global climate models] to bring us to a point where all of this is made clear is much needed, and may take much time." And they thoughtfully remind us - in the interim - that "although media reports of both floods and global flood damage are on the increase, there is still no Mauna-Loa-like record (see Vorosmarty, 2002) that shows a global increase in flood frequency or magnitude."
Sherwood, Keith and Craig Idso
Kundzewicz, Z.W., Kanae, S., Seneviratne, S.I., Handmer, J., Nicholls, N., Peduzzi, P., Mechler, R., Bouwer, L.M., Arnell, N., Mach, K., Muir-Wood, R., Brakenridge, G.R., Kron, W., Benito, G., Honda, Y., Takahashi, K. and Sherstyukov, B. 2013. Flood risk and climate change: global and regional perspectives. Hydrological Sciences Journal: 10.1080/02626667.2013.857411.
Vorosmarty, C.J. 2002. Global change, the water cycle, and our search for Mauna Loa. Hydrological Processes 16: 135-139.