Great Stories

Although remnants of the Laurentide Ice Sheet did not disappear until about 7 Ka, the early to mid-Holocene (4,500 to 10,000 years) has often been considered to have been warmer than the last 4,500 years. A thermal maximum occurred at about 6 to 7 Ka (Figure 5.18). Conclusions about the […]

The Phanerozoic covers the last 570 Ma of Earth history, made up of three Eras, the Palaeozoic (570 to 225Ma), Mesozoic (225 to 65Ma) and Cenozoic (65Ma to present) (see appendix). Each Era is divided up into different Periods, and each Period is divided into a number of Epochs. The […]

Although deglaciation had been taking place for at least 4,000 years, a rapid deterioration (cooling) in climate occurred at about 10 to 11Ka, roughly marking the boundary between Holocene and Pleistocene Epochs. This event is known as the Younger Dryas Cooling. The North Atlantic polar front readvanced far southward to […]

Life may be found in almost any environment existing on Earth. Nevertheless, in a discussion on the climate system, it is convenient to regard the biosphere as a discrete component, like the atmosphere, oceans and cryosphere. The biosphere, both on land and in the oceans, affects the albedo of the […]

The three components of the orbital variations together effect both the total flux of incoming solar radiation and also the temporal and spatial distribution of that energy. These variations have the potential to influence the energy budget of the climate system (Milankovitch, 1941; Berger 1978), and can therefore be regarded […]

As snow and ice accumulates on polar and alpine ice caps and sheets, it lays down a record of the environmental conditions at the time of its formation. Information concerning these conditions can be extracted from ice and snow that has survived the summer melt by physical and chemical means. […]

The study of the annual growth of trees and the consequent assembling of long, continuous chronologies for use in dating wood is called dendrochronology. The study of the relationships between annual tree growth and climate is called dendroclimatology. Dendroclimatology offers a high resolution (annual) form of palaeoclimate reconstruction for most […]

Wind is usually measured by a cup anemometer which rotates about a vertical axis perpendicular to the direction of the wind. The exposure of wind instruments is important (Johnson & Linacre, 1978); any obstruction close by will affect measurements. Wind direction is also measured by means of a vane, accurately […]

The pre-Quaternary spans 99.95% of Earth History (see appendix). Nevertheless, knowledge of pre-Quaternary climates is significantly poorer than that of the last 2 million years. Going further back in time, more and more evidence for past climate change will have been removed by subsequent climatic episodes. 5.2.1. Precambrian Climates The […]

Through much of the history of climate modelling, division between modelling and observational studies has hampered the development of both sides. The coupling of these theoretical and empirical disciplines, to test both model accuracy and understanding gained from analysis of observational data, has only recently been addressed. Much of the […]