Global climate, we are told, was more or less constant before man began emitting greenhouse gases. This is what a number of IPCC scientists tried (and are still trying) to tell us with their fabricated hockey sticks.
A new 9170-year paleohydrologic reconstruction by Kirby et al is out. The team of scientists have examined deposits from Lower Bear Lake in the San Bernardino Mountains, in southwest United States. These mountains are the source region for the Mojave River.
The authors write in the abstract that “the new multi-proxy record is characterized by alternating organic-rich/carbonate-rich sediment units”, which they say can be interpreted “to reflect hydrologically-forced changes in the lake’s depositional environment”.
What result did they find? (My emphasis):
Our interpretation of the proxy data indicates nine decadal-to-multi-centennial pluvial episodes [periods of heavy precipitation] over the past 9170 cal yr BP. Of these nine inferred pluvials, five are interpreted as more pronounced based on their combined proxy interpretations: (PE-V) 9170?–8250, (PE-IV) 7000–6400, (PE-III) 3350–3000, (PE-II) 850–700, and (PE-I) 500–476 (top of core) cal yr BP.”
This tells us that precipitation amounts were high in the region of the San Bernardino mountains during those periods. Moreover, the authors add that this was not a locally isolated phenomenon, but was widespread over the general region:
Our comparison extends north also to Tulare Lake, which drains the southcentral-western Sierra Nevada Mountains. This temporally and spatially coherent signal indicates that a similar climate forcing acted to increase regional wetness at various times during the past 9170 cal yr BP. […] Holocene pluvial episodes are associated with changing the frequency of large winter storms that track across a broad region at decadal-to-multi-centennial timescales.”
Centennial time scale? This would indicate something more at work than ocean cycles, which are internal within the climate system, and suggests that other natural, external cycles are at work. However, IPCC scientists like to suggest that these natural factors no longer play a role today, that they stopped working a hundred years ago, and so leave them out of their climate models.
According to the German-language Wikipedia, in paleoclimatology pluvials are usually in connection with unusually strong precipitation – geologically shown to have occurred mainly in tropical and subtropical regions. Good examples are areas that are deserts today, e.g. the mudpans of the Sahara, Lake Bonneville in western Utah, Lake Moeris Faiyum, Egypt, and Lake Chad.
Overall the cold periods on the Earth were less wet than the warm periods.
All that is left to do is to compare the results of the new study to solar activity over the last ten thousand years. Maybe we’ll find that there was cyclic volcanic activity driving it all!