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Atmospheric Effects
Published in Wayne T. Davis, Joshua S. Fu, Thad Godish, Air Quality, 2021
Wayne T. Davis, Joshua S. Fu, Thad Godish
Changes in the sun’s luminosity associated with sunspots and other sun surface activity have been proposed as a cause of significant climatic change. The Little Ice Age, a period of global cooling observed worldwide during the fourteenth to nineteenth centuries, was associated with a significant decline in sunspot activity. The Little Ice Age was accompanied by (1) the advance of European mountain glaciers, (2) lower average winter temperatures in central Britain, (3) the abandonment of cereal cultivation in Iceland and vineyards in England, (4) the abandonment of settlements in Greenland, and (5) winter freezing of the North Sea and canals in Venice. It is probable that global surface temperatures were lower by 1°C (1.8°F) or more during that period, and that precipitation patterns were also changed.
Energy and Changes in the Environment
Published in Michael Frank Hordeski, Hydrogen & Fuel Cells: Advances in Transportation and Power, 2020
During the colder periods, icebergs floated as far south as Portugal. One of these cold spells probably forced the Vikings out of Greenland. This period is known as the Little Ice Age, which lasted from about 1400 to 1900.
Water and the Hydrosphere
Published in Dexter Perkins, Kevin R. Henke, Adam C. Simon, Lance D. Yarbrough, Earth Materials, 2019
Dexter Perkins, Kevin R. Henke, Adam C. Simon, Lance D. Yarbrough
Figure 12.34 shows two views of Alaska’s Muir Glacier in Glacier Bay National Park. The photos were taken in August of 1941 and 2004. During the intervening 63 years, the front of the glacier moved back about 12 kilometers (7 miles) and ice thickness decreased by more than 800 meters (2600 feet). Thus, there has been a huge loss of ice volume. Around the globe, the areal extent of glaciers has been decreasing, on average, since the end of the so-called Little Ice Age (a cool period of time about 150 years ago). Today, about 10% of Earth’s land is covered by glaciers; during the last ice age, coverage was about 32%. At present, the rate of glacier melting in polar regions is the fastest it has been any time during the past 10,000 years, and Greenland glaciers are melting faster than any others. Because glaciers contribute substantially to Earth’s albedo (reflection of solar energy), as Earth’s glaciers disappear, less of the sun’s energy will be reflected into space, and the rate of global warming and glacier melting will accelerate. Perhaps the biggest threat posed by melting glaciers is sea level rise. In the past 100 years, melting glaciers caused global sea level to rise by 11 centimeters, and if all the glaciers melt, the world’s oceans will rise by an additional 70 meters flooding many large cities.
Bedload transport: a walk between randomness and determinism. Part 1. The state of the art
Published in Journal of Hydraulic Research, 2020
Bedload transport is a specific form of sediment transport, which involves coarse particles (sand, gravel or coarser particles) rolling or saltating along the streambed. In Europe, the increased construction of navigation channels in the eighteenth century gave impetus to the creation of hydraulics – the science of water flow (Levi, 1995). The issue of bed erosion and stability had become progressively more problematic as more channels were built across Europe. The first qualitative description of the erosive action of rivers appeared in 1697 in the book “Della natura de' fiumi” (On the nature of rivers) by the Italian polymath, Doménico Guglielmini. Today it is largely forgotten, but its influence was significant in the eighteenth century (Simons & Şentük, 1992). At the end of the Little Ice Age, in the nineteenth century, many European countries faced major flooding. For the first time in European history, nationwide mitigation strategies based on river engineering and reforestation were implemented to control water flow on a large scale (Ford, 2016; Vischer, 2003). Rivers and mountain streams mobilizing coarse sediment posed their own specific problems, and these pushed engineers to make the distinction between bedload and suspension. Indeed, bedload transport theory appeared at that time, with the earliest quantitative formulation of a bedload equation usually being attributed to Paul du Boys, a young French engineer studying the Rhone (du Boys, 1879; Hager,2005, 2009).
Post-water political-economics
Published in International Journal of Water Resources Development, 2023
Finally, politicians will be quick to blame outsiders for collapsing prosperity and future prospects. For reference, consider the impacts of the Little Ice Age(s) that took place between 1400–1850: war and invasion, famine and hunger, the murder of ‘witches’, Jews and other scapegoats. Cold and ice differ from heat and drought in temperature but not in the ways they disrupt food systems, security and cooperation. The middle classes are more likely to abandon the poor and defenceless than accept a lower quality of life. Our concept of civilization will change – or break (Bendell, 2018; Gardiner, 2006).