There have been significant changes in sea level over the past two million years, and a complete understanding of natural cycles of change as well as anthropogenic effects is imperative for future ...global development. This book reviews the history of research into these sea-level changes and summarises the methods and analytical approaches used to interpret evidence for sea-level changes. It provides an overview of changing climates during the Quaternary, examines processes responsible for global variability of sea-level records, and presents detailed reviews of sea-level changes for the Pleistocene and Holocene. The book concludes by discussing current trends in sea levels and likely future sea-level changes. This is an important and authoritative resource for academic researchers and graduate and advanced undergraduate students working in tectonics, stratigraphy, geomorphology, physical geography, environmental science and other aspects of Quaternary studies.
The fascinating story of how a harsh terrain that resembled modern Antarctica has been transformed gradually into the forests, grasslands, and wetlands we know today.
The arid region of Central Asia is one of the world's major sources of dust and exerts a significant influence on marine ecosystems, atmospheric carbon dioxide concentrations, the global radiation ...budget, and thus global climate change. Recent global warming has considerably reduced mid-latitude net precipitation by decreasing the latitudinal temperature gradient between the Equator and the Arctic; however, the influence of ice sheet and solar insolation on moisture evolution in Central Asia during the Holocene remains uncertain. Here we show that the relative wet conditions during the early Holocene in northern Central Asia (NCA) were controlled principally by the southern position of the mid-latitude Westerlies under the negative phase of the North Atlantic Oscillation (NAO), a pattern that was influenced by the substantial remnants of the Laurentide and Fennoscandian ice sheets. Subsequent northward migration of the mid-latitude Westerlies under a positive NAO phase resulted in persistent drought conditions during the middle Holocene thermal maximum, due to the combined effects of relatively higher summer insolation and Arctic amplification as well as sea ice loss. In contrast, southward migration of the mid-latitude Westerlies since approximately 3.6 cal kyr BP, driven by declining summer insolation and coincident with the negative NAO phase, increased regional precipitation towards to persistent relatively wet conditions in Central Asia. This reconstructed pattern of Holocene moisture availability contrasts markedly with the increase in precipitation over Central Asia under the current anthropogenically forced warming, thereby justifying further investigation into the multiple forcing mechanisms driving natural and anthropogenic climate change.
The latitudinal temperature gradient between the Equator and the poles influences atmospheric stability, the strength of the jet stream and extratropical cyclones
. Recent global warming is weakening ...the annual surface gradient in the Northern Hemisphere by preferentially warming the high latitudes
; however, the implications of these changes for mid-latitude climate remain uncertain
. Here we show that a weaker latitudinal temperature gradient-that is, warming of the Arctic with respect to the Equator-during the early to middle part of the Holocene coincided with substantial decreases in mid-latitude net precipitation (precipitation minus evapotranspiration, at 30° N to 50° N). We quantify the evolution of the gradient and of mid-latitude moisture both in a new compilation of Holocene palaeoclimate records spanning from 10° S to 90° N and in an ensemble of mid-Holocene climate model simulations. The observed pattern is consistent with the hypothesis that a weaker temperature gradient led to weaker mid-latitude westerly flow, weaker cyclones and decreased net terrestrial mid-latitude precipitation. Currently, the northern high latitudes are warming at rates nearly double the global average
, decreasing the Equator-to-pole temperature gradient to values comparable with those in the early to middle Holocene. If the patterns observed during the Holocene hold for current anthropogenically forced warming, the weaker latitudinal temperature gradient will lead to considerable reductions in mid-latitude water resources.
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