Call number:
9783030104665 (e-book)
Description / Table of Contents:
It is not so long ago (a mere 17,000 years – a blink in geologic time) that vast areas of the Northern Hemisphere were covered with ice sheets up to two miles thick, lowering the oceans by more than 120 m. By 11,000 years ago, most of the ice was gone. Evidence from polar ice cores and ocean sediments show that Ice Ages were persistent and recurrent over the past 800,000 years. The data suggests that Ice Ages were the normal state, and were temporarily interrupted by interglacial warm periods about nine times during this period. Quasi-periodic variations in the Earth cause the solar input to high northern latitudes to vary with time over thousands of years. The widely accepted Milankovitch theory implies that the interglacial warm periods are associated with high solar input to high northern latitudes. However, many periods of high solar input to high northern latitudes occur during Ice Ages while the ice sheets remain. The data also indicates that Ice Ages will persist regardless of solar input to high northern latitudes, until several conditions are met that are necessary to generate a termination of an Ice Age. An Ice Age will not terminate until it has been maturing for many tens of thousands of years leading to a reduction of the atmospheric CO2 concentration to less than 200 ppm. At that point, CO2 starvation coupled with lower temperatures will cause desertification of marginal regions, leading to the generation of large quantities of dust. High winds transfer this dust to the ice sheets greatly increasing their solar absorptivity, and at the next up-lobe in the solar input to high northern latitudes, solar power melts the ice sheets over about a 6,000-year interval. A warm interglacial period follows, during which dust levels drop remarkably. Slowly but surely, ice begins accumulating again at high northern latitudes and an incipient new Ice Age begins. This third edition presents data and models to support this theory
Type of Medium:
12
Pages:
1 Online-Ressource (xxiii, 346 Seiten)
,
Illustrationen, Diagramme, Karten (überwiegend farbig)
Edition:
Tthird edition
ISBN:
9783030104665
,
978-3-030-10466-5
URL:
https://doi.org/10.1007/978-3-030-10466-5
Language:
English
Note:
Contents
1 History and Description of Ice Ages
1.1 Discovery of Ice Ages
1.2 Description of Ice Sheets
1.3 Vegetation During LGM
1.3.1 LGM Climate
1.3.2 Global Flora
1.3.3 Ice Age Forests
1.4 Vegetation and Dust Generation During the LGM
1.4.1 Introduction: Effect of Low CO2 on Plants
1.4.2 C3 and C4 Flora Differences
1.4.3 Effects of Low CO2 on Tree Lines
1.4.4 Source of the LGM Dust
2 Variability of the Earth’s Climate
2.1 Factors that Influence Global Climate
2.2 Stable Extremes of the Earth’s Climate
2.3 Ice Ages in the Recent Geological Past
3 Ice Core Methodology
3.1 History of Ice Core Research
3.2 Dating Ice Core Data
3.2.1 Introduction
3.2.2 Age Markers
3.2.3 Counting Layers Visually
3.2.4 Layers Determined by Measurement
3.2.5 Ice Flow Modeling
3.2.6 Other Dating Methods
3.2.7 Synchronization of Dating of Ice Cores from Greenland and Antarctica
3.2.8 GISP2 Experience
3.2.9 Tuning
3.2.10 Flimsy Logic
3.3 Processing Ice Core Data
3.3.1 Temperature Estimates from Ice Cores
3.3.2 Temperature Estimates from Borehole Models
3.3.3 Climate Variations
3.3.4 Trapped Gases
4 Ice Core Data
4.1 Greenland Ice Core Historical Temperatures
4.2 Antarctica Ice Core Historical Temperatures
4.2.1 Vostok and EPICA Data
4.2.2 Homogeneity of Antarctic Ice Cores
4.3 North-South Synchrony
4.3.1 Direct Comparison of Greenland and Antarctica Ice Core Records
4.3.2 Sudden Changes
4.3.3 Interpretation of Sudden Change in Terms of Ocean Circulation
4.3.4 Seasonal Variability of Precipitation
4.4 Data from High-Elevation Ice Cores
4.5 Carbon Dioxide
4.5.1 Measurements
4.5.2 Explanations
4.6 Dust in Ice Cores
5 Ocean Sediment Data
5.1 Introduction
5.2 Chronology
5.3 Universality of Ocean Sediment Data
5.4 Summary of Ocean Sediment Ice Volume Data
5.5 Comparison of Ocean Sediment Data with Polar Ice Core Data
5.6 Historical Sea Surface Temperatures
5.7 Ice-Rafted Debris
6 Other Data Sources
6.1 Devil’s Hole
6.1.1 Devil’s Hole Data
6.1.2 Comparison of Devil’s Hole Data with Ocean Sediment Data
6.1.3 Devil’s Hole: Global or Regional Data?
6.1.4 Comparison of Devil’s Hole Data with Vostok Data
6.1.5 The Continuing Controversy
6.2 Speleothems in Caves
6.3 Magnetism in Rocks and Loess
6.3.1 Magnetism in Loess
6.3.2 Rock Magnetism in Lake Sediments
6.4 Pollen Records
6.5 Physical Indicators
6.5.1 Ice Sheet Moraines
6.5.2 Coral Terraces
6.5.3 Mountain Glaciers
6.6 Red Sea Sediments
7 Overview of the Various Models for Ice Ages
7.1 Introduction
7.2 Variability of the Sun
7.3 Astronomical Theory
7.4 Volcanism
7.5 Greenhouse Gases
7.6 Role of the Oceans
7.6.1 Glacial-Interglacial Cycles: The Consensus View
7.6.2 Sudden Climate Change - The Consensus View
7.6.3 Wunsch’s Objections
7.7 Models Based on Clouds
7.7.1 Extraterrestrial Dust Accretion
7.7.2 Clouds Induced by Cosmic Rays
7.7.3 Ocean–Atmosphere Model
7.8 Models Based on the Southern Hemisphere
8 Variability of the Earth’s Orbit: Astronomical Theory
8.1 Introduction
8.2 Variability of the Earth’s Orbit
8.2.1 Variability Within the Orbital Plane
8.2.2 Variability of the Orbital Plane
8.3 Calculation of Solar Intensities
8.4 Importance of Each Orbital Parameter
8.5 Historical Solar Irradiance at Higher Latitudes
8.6 Connection Between Solar Variability and Glaciation/Deglaciation Cycles According to Astronomical Theory
8.6.1 Models for Ice Volume
8.6.2 Review of the Imbries’ Model
8.6.3 Memory Model
8.6.4 Modification of Paillard Model
8.7 Models Based on Eccentricity or Obliquity
8.7.1 A Model Based on Eccentricity
8.7.2 The Middle-Pleistocene Transition (MPT)
9 Comparison of Astronomical Theory with Data
9.1 Ice Volume Versus Solar Input
9.2 Spectral Analysis
9.2.1 Introduction
9.2.2 Spectral Analysis of Solar and Paleoclimate Data
10 Interglacials
11 Terminations of Ice Ages
11.1 Abstract
11.2 Background
11.3 Terminations
11.4 North or South (or Both)?
11.5 Models Based on CO 2 and the Southern Hemisphere
11.6 Climate Models for Terminations of Ice Ages
11.7 Model Based on Solar Amplitudes
11.8 Dust as the Driver for Terminations
11.8.1 Introduction
11.8.2 Antarctic Dust Data
11.8.3 Correlation of Ice Core Dust Data with Terminations
11.8.4 Dust Levels on the Ice Sheets
11.8.5 Optical Properties of Surface Deposited Dust
11.8.6 Source of the Dust
11.8.7 Ice Sheet Margins
11.9 Model Based on Solar Thresholds
11.10 The Milankovitch Model Versus the Most Likely Model
11.10.1 Criteria for a Theory
11.10.2 The “Milankovitch” Model
11.10.3 The Most Likely Model
11.10.4 Unanswered Questions
12 Status of Our Understanding
References
Index
