دايره‌المعارف ‌آب و هواشناسى و محیط های ديرينه

              Encyclopedia of Paleoclimatology and Ancient Environments  

                                 (Encyclopedia of Earth Sciences)

                                     

                                                       by : Vivien Gornitz  

                               

size : 24 MB                              

   Preface                               

The growing levels of atmospheric greenhouse gases generated

by anthropogenic activities are already beginning to affect the

Earth's climate, according to the latest report by the Intergovernmental

Panel on Climate Change, and concern is mounting over

potential adverse consequences to society. However, Earth's climate

has shifted dramatically and frequently during the last few

million years, alternating between ice ages, when vast glaciers

covered Northern Europe and much of North America, and

interglacials—warm periods much like today. Farther back in

geologic time, climates have differed even more from the present.

Could human actions push the Earth's climate system into

an unstable mode, beyond the relatively mild oscillations of the

last few millennia? To fully understand the unusual changes of

the 20th century and possible future trends, these need to be

placed in a longer-term context extending well beyond the period

of instrumental records. Paleoclimatology—the study of climates

of the past–may provide us with insights into the workings of the

modern climate system. By reconstructing ancient climates using

natural “archives” of environmental change recorded in trees, corals,

cave deposits, ice cores, lake and ocean sediments, and running

computer models, paleoclimatologists can place bounds on past

climate variability and help us anticipate possible future changes.

The Encyclopedia of Paleoclimatology and Ancient Environments,

                                                                       a companion volume to the recently-published

Encyclopedia of World Climatology, provides the reader with

an entry point to the rapidly expanding field of paleoclimatology.

Highly interdisciplinary, paleoclimatology integrates information

from a broad array of disciplines in the geosciences,

spanning across stratigraphy, geomorphology, glaciology, paleoecology,

paleobotany, isotope geochemistry, geochronology, and

geophysics, among others. The encyclopedia covers the entire

span of the Earth's climate history from the early Precambrian

to the Little Ice Age, and also offers an interplanetary comparison

with the contrasting climates of Mars and Venus in 230 informative

articles written by over 200 well known international

experts. The climates of the past were the product of closely

inter-connected processes that shaped the Earth's atmosphere,

lithosphere, and biosphere. Therefore, the separation between

topics is somewhat arbitrary and a certain degree of overlap

is inevitable. However, since authors often approach similar

topics from differing perspectives, these differences can provide

a fuller picture overall. The volume is abundantly illustrated with

line-drawings, black-white and color photographs. Articles are

arranged alphabetically, with extensive bibliographies and crossreferences.

March 2008

                                                                Vivien Gornitz