Reading the Landscape

Abstract

In this chapter the history of European knowledge of glaciers and their influence on landscape and climate is traced, from Ignatz Venetz-Sitten and Jean de Charpentier's glacial hypothesis, to Louis Agassiz's and Karl Schimper's theory of the Ice Age, and the gradual acceptance of the latter by the end of the 19th century. Further details of climate history were later revealed through fossilised flora and fauna in sediment layers (strata) and various dating methods. By the late 20th century, temperature records of several glacial and interstadial periods had been derived from oxygen isotopes in fossilised shells in deep-sea sediment strata and glacial ice cores from Greenland and Antarctica. Theories on the astronomical causes of climate fluctuations are outlined, e.g. those of James Croll and Milutin Milankovitch on the influence of Earth's orbital pattern and axial precession and tilt on solar radiation penetrating the Earth's atmosphere. A summary of glacial epochs from 130,000 years ago until the present time is then related, with reference to specific periods, e.g. late glacial, the Holocene and the Little Ice Age. The role of the North Atlantic and the transportation of tropical oceanic heat in climate fluctuations is also discussed. A brief history of glaciers in Iceland follows, from the settlement of the country until the present day. Finally, there is a discussion on the current climate of Earth and possible future changes. 2.1 The Long, Winding Road to Understanding Ice Ages For thousands of years, the peoples of the northern reaches of Europe and America inhabited an environment shaped by ice-age glaciers, living among glacially polished rock formations and erratic boulders on ancient outwash plains and in glacially-gouged valleys between jagged crests of mountains (Figs. 2.1, 2.2, 2.3 and 2.4). But even though these traces of ancient glaciers were there for all to see, it