Were the Dark Ages Triggered by Volcano-Related Climate Change? (English Edition) [Kindle-editie] beoordelingen het boek quotes

Modern history has its origins in the tumultuous 6thand 7thcenturies. During this period agricultural failures and the emergence of the plague contributed to: (1) the demise of ancient super cities, old Persia, Indonesian civilizations, the Nasca culture of South America, and southern Arabian civilizations; (2) the schism of the Roman Empire with the conception of many nation states and the re-birth of a united China; and (3) the origin and spread of Islam while Arian Christianity disappeared. In his book, Catastrophe An Investigation into the Origins of the Modern World, author David Keys explores history and archaeology to link all of these human upheavals to climate destabilization brought on by a natural catastrophe, with strong evidence from tree-ring and ice-core data that it occurred in 535 AD. With no supporting evidence for an impact-related event, I worked with Keys to narrow down the possibilities for a volcanic eruption that could affect both hemispheres and bring about several decades of disrupted climate patterns, most notably colder and drier weather in Europe and Asia, where descriptions of months with diminished sun light, persistent cold, and anomalous summer snow falls are recorded in 6th-century written accounts. Writings from China and Indonesia describe rare atmospheric phenomena that possibly point to a volcano in the Indonesian arc. Although radiocarbon dating of eruptions in that part of the world are spotty, there is strong bathymetric and volcanic evidence that Krakatau might have experienced a huge caldera eruption. Accordingly, I encouraged a scientific expedition to be led by Haraldur Sigurdsson to the area. The expedition found a thick pyroclastic deposit, bracketed by appropriate radiometric dates, that suggests such a caldera collapse of a “Proto-Krakatau” did occur perhaps in the6thcentury. Bathymetry indicates a caldera some 40 to 60 km in diameter that, with collapse below sea level, could have formed the Sunda Straits, separating Java from Sumatra, as suggested by ancient Javanese historical writings. Such a caldera collapse likely involved eruption of several hundred cubic kilometers of pyroclastic debris, several times larger than the 1815 eruption of Tambora. This hypothetical eruption likely involved magma-seawater interaction, as past eruptions of Krakatau document, but on a tremendous scale. Computer simulations of the eruption indicate that the interaction could have produced a plume from 25 to >50 km high,carrying from 50 to 100 km3of vaporized seawater into the atmosphere. Although most of the vapor condenses and falls out from low altitudes, still large quantities are lofted into the stratosphere, forming ice clouds with super fine (<10 μm) hydrovolcanic ash. Discussions with global climate modelers at Los Alamos National Laboratory led me to preliminary calculations that such a plume of ash and ice crystals could form a significant cloud layer over much of the northern and southern hemispheres. Orders of magnitude larger than previously studied volcanic plumes, its dissipation and impact upon global albedo, the tropopause height, and stratospheric ozone are unknown but certainly within possibilities for climate destabilization lasting years or perhaps several decades. If this volcanic hypothesis is correct, the global, domino-like affects upon epidemics, agriculture, politics, economics, and religion are far-reaching, elevating the potential role of volcanism as a major climate control, and demonstrating the intimate link between human affairs and nature.