Geophysical, Archaeological, and Historical Evidence Support a Solar-Output Model for Climate Change
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
Sea Level and Global Ice Volumes from the Last Glacial Maximum to the Holocene
Sea level and global ice volumes from the Last Glacial Maximum to the Holocene Kurt Lambecka,b,1, Hélène Roubya,b, Anthony Purcella, Yiying Sunc, and Malcolm Sambridgea aResearch School of Earth Sciences, The Australian National University, Canberra, ACT 0200, Australia; bLaboratoire de Géologie de l’École Normale Supérieure, UMR 8538 du CNRS, 75231 Paris, France; and cDepartment of Earth Sciences, University of Hong Kong, Hong Kong, China This contribution is part of the special series of Inaugural Articles by members of the National Academy of Sciences elected in 2009. Contributed by Kurt Lambeck, September 12, 2014 (sent for review July 1, 2014; reviewed by Edouard Bard, Jerry X. Mitrovica, and Peter U. Clark) The major cause of sea-level change during ice ages is the exchange for the Holocene for which the direct measures of past sea level are of water between ice and ocean and the planet’s dynamic response relatively abundant, for example, exhibit differences both in phase to the changing surface load. Inversion of ∼1,000 observations for and in noise characteristics between the two data [compare, for the past 35,000 y from localities far from former ice margins has example, the Holocene parts of oxygen isotope records from the provided new constraints on the fluctuation of ice volume in this Pacific (9) and from two Red Sea cores (10)]. interval. Key results are: (i) a rapid final fall in global sea level of Past sea level is measured with respect to its present position ∼40 m in <2,000 y at the onset of the glacial maximum ∼30,000 y and contains information on both land movement and changes in before present (30 ka BP); (ii) a slow fall to −134 m from 29 to 21 ka ocean volume. -
The Climate of the Last Glacial Maximum: Results from a Coupled Atmosphere-Ocean General Circulation Model Andrew B
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 104, NO. D20, PAGES 24,509–24,525, OCTOBER 27, 1999 The climate of the Last Glacial Maximum: Results from a coupled atmosphere-ocean general circulation model Andrew B. G. Bush Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Canada S. George H. Philander Program in Atmospheric and Oceanic Sciences, Department of Geosciences, Princeton University Princeton, New Jersey Abstract. Results from a coupled atmosphere-ocean general circulation model simulation of the Last Glacial Maximum reveal annual mean continental cooling between 4Њ and 7ЊC over tropical landmasses, up to 26Њ of cooling over the Laurentide ice sheet, and a global mean temperature depression of 4.3ЊC. The simulation incorporates glacial ice sheets, glacial land surface, reduced sea level, 21 ka orbital parameters, and decreased atmospheric CO2. Glacial winds, in addition to exhibiting anticyclonic circulations over the ice sheets themselves, show a strong cyclonic circulation over the northwest Atlantic basin, enhanced easterly flow over the tropical Pacific, and enhanced westerly flow over the Indian Ocean. Changes in equatorial winds are congruous with a westward shift in tropical convection, which leaves the western Pacific much drier than today but the Indonesian archipelago much wetter. Global mean specific humidity in the glacial climate is 10% less than today. Stronger Pacific easterlies increase the tilt of the tropical thermocline, increase the speed of the Equatorial Undercurrent, and increase the westward extent of the cold tongue, thereby depressing glacial sea surface temperatures in the western tropical Pacific by ϳ5Њ–6ЊC. 1. Introduction and Broccoli, 1985a, b; Broccoli and Manabe, 1987; Broccoli and Marciniak, 1996]. -
The History of Ice on Earth by Michael Marshall
The history of ice on Earth By Michael Marshall Primitive humans, clad in animal skins, trekking across vast expanses of ice in a desperate search to find food. That’s the image that comes to mind when most of us think about an ice age. But in fact there have been many ice ages, most of them long before humans made their first appearance. And the familiar picture of an ice age is of a comparatively mild one: others were so severe that the entire Earth froze over, for tens or even hundreds of millions of years. In fact, the planet seems to have three main settings: “greenhouse”, when tropical temperatures extend to the polesand there are no ice sheets at all; “icehouse”, when there is some permanent ice, although its extent varies greatly; and “snowball”, in which the planet’s entire surface is frozen over. Why the ice periodically advances – and why it retreats again – is a mystery that glaciologists have only just started to unravel. Here’s our recap of all the back and forth they’re trying to explain. Snowball Earth 2.4 to 2.1 billion years ago The Huronian glaciation is the oldest ice age we know about. The Earth was just over 2 billion years old, and home only to unicellular life-forms. The early stages of the Huronian, from 2.4 to 2.3 billion years ago, seem to have been particularly severe, with the entire planet frozen over in the first “snowball Earth”. This may have been triggered by a 250-million-year lull in volcanic activity, which would have meant less carbon dioxide being pumped into the atmosphere, and a reduced greenhouse effect. -
Immersion Into Noise
Immersion Into Noise Critical Climate Change Series Editors: Tom Cohen and Claire Colebrook The era of climate change involves the mutation of systems beyond 20th century anthropomorphic models and has stood, until recent- ly, outside representation or address. Understood in a broad and critical sense, climate change concerns material agencies that im- pact on biomass and energy, erased borders and microbial inven- tion, geological and nanographic time, and extinction events. The possibility of extinction has always been a latent figure in textual production and archives; but the current sense of depletion, decay, mutation and exhaustion calls for new modes of address, new styles of publishing and authoring, and new formats and speeds of distri- bution. As the pressures and re-alignments of this re-arrangement occur, so must the critical languages and conceptual templates, po- litical premises and definitions of ‘life.’ There is a particular need to publish in timely fashion experimental monographs that redefine the boundaries of disciplinary fields, rhetorical invasions, the in- terface of conceptual and scientific languages, and geomorphic and geopolitical interventions. Critical Climate Change is oriented, in this general manner, toward the epistemo-political mutations that correspond to the temporalities of terrestrial mutation. Immersion Into Noise Joseph Nechvatal OPEN HUMANITIES PRESS An imprint of MPublishing – University of Michigan Library, Ann Arbor, 2011 First edition published by Open Humanities Press 2011 Freely available online at http://hdl.handle.net/2027/spo.9618970.0001.001 Copyright © 2011 Joseph Nechvatal This is an open access book, licensed under the Creative Commons By Attribution Share Alike license. Under this license, authors allow anyone to download, reuse, reprint, modify, distribute, and/or copy this book so long as the authors and source are cited and resulting derivative works are licensed under the same or similar license. -
A Possible Late Pleistocene Impact Crater in Central North America and Its Relation to the Younger Dryas Stadial
A POSSIBLE LATE PLEISTOCENE IMPACT CRATER IN CENTRAL NORTH AMERICA AND ITS RELATION TO THE YOUNGER DRYAS STADIAL SUBMITTED TO THE FACULTY OF THE UNIVERSITY OF MINNESOTA BY David Tovar Rodriguez IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE Howard Mooers, Advisor August 2020 2020 David Tovar All Rights Reserved ACKNOWLEDGEMENTS I would like to thank my advisor Dr. Howard Mooers for his permanent support, my family, and my friends. i Abstract The causes that started the Younger Dryas (YD) event remain hotly debated. Studies indicate that the drainage of Lake Agassiz into the North Atlantic Ocean and south through the Mississippi River caused a considerable change in oceanic thermal currents, thus producing a decrease in global temperature. Other studies indicate that perhaps the impact of an extraterrestrial body (asteroid fragment) could have impacted the Earth 12.9 ky BP ago, triggering a series of events that caused global temperature drop. The presence of high concentrations of iridium, charcoal, fullerenes, and molten glass, considered by-products of extraterrestrial impacts, have been reported in sediments of the same age; however, there is no impact structure identified so far. In this work, the Roseau structure's geomorphological features are analyzed in detail to determine if impacted layers with plastic deformation located between hard rocks and a thin layer of water might explain the particular shape of the studied structure. Geophysical data of the study area do not show gravimetric anomalies related to a possible impact structure. One hypothesis developed on this works is related to the structure's shape might be explained by atmospheric explosions dynamics due to the disintegration of material when it comes into contact with the atmosphere. -
Geological Time Conventions and Symbols
AL SOCIET IC Y G O O F L A O M E E G R I E C H A T GROUNDWORK Furthering the Influence of Earth Science internally and with respect to SI (Le Système international Geological Time d’unités)” (Holden et al., 2011a, 2011b), because that is the justification being offered in support of a change. This assertion cannot be sustained. No one objects to the storming of the Conventions and Symbols Bastille on 14 July 1789 (a date) or to the construction of Stonehenge from 2600–1600 BC (an interval specified by two Nicholas Christie-Blick, Dept. of Earth and Environmental dates). In the case of the latter, we say that the job took 1000 Sciences and Lamont-Doherty Earth Observatory of Columbia years, not 1000 BC. The distinction between geohistorical dates University, Palisades, New York 10964, USA; [email protected] and spans of geological time is conceptually analogous. There is no internal inconsistency, and the International System of Units All science involves conventions. Although subordinate to the (SI) rules don’t apply to dates in either case because points in task of figuring out how the natural world functions, such time are not units, even if they are specified in years (Aubry et conventions are necessary for clear communication, and because al., 2009). The year, moreover, is not a part of the SI. It cannot be they are a matter of choice rather than discovery, they ought to a “derived unit of time,” the designation proposed by the task reflect the diverse preferences and needs of the communities for group, because under SI conventions “derived units are products which they are intended. -
Modelling the Concentration of Atmospheric CO2 During the Younger Dryas Climate Event
Climate Dynamics (1999) 15:341}354 ( Springer-Verlag 1999 O. Marchal' T. F. Stocker'F. Joos' A. Indermu~hle T. Blunier'J. Tschumi Modelling the concentration of atmospheric CO2 during the Younger Dryas climate event Received: 27 May 1998 / Accepted: 5 November 1998 Abstract The Younger Dryas (YD, dated between 12.7}11.6 ky BP in the GRIP ice core, Central Green- 1 Introduction land) is a distinct cold period in the North Atlantic region during the last deglaciation. A popular, but Pollen continental sequences indicate that the Younger controversial hypothesis to explain the cooling is a re- Dryas cold climate event of the last deglaciation (YD) duction of the Atlantic thermohaline circulation (THC) a!ected mainly northern Europe and eastern Canada and associated northward heat #ux as triggered by (Peteet 1995). This event has been dated by annual layer counting between 12 700$100 y BP and glacial meltwater. Recently, a CH4-based synchroniza- d18 11550$70 y BP in the GRIP ice core (72.6 3N, tion of GRIP O and Byrd CO2 records (West Antarctica) indicated that the concentration of atmo- 37.6 3W; Johnsen et al. 1992) and between 12 940$ 260 !5. y BP and 11 640$ 250 y BP in the GISP2 ice core spheric CO2 (CO2 ) rose steadily during the YD, sug- !5. (72.6 3N, 38.5 3W; Alley et al. 1993), both drilled in gesting a minor in#uence of the THC on CO2 at that !5. Central Greenland. A popular hypothesis for the YD is time. Here we show that the CO2 change in a zonally averaged, circulation-biogeochemistry ocean model a reduction in the formation of North Atlantic Deep when THC is collapsed by freshwater #ux anomaly is Water by the input of low-density glacial meltwater, consistent with the Byrd record. -
The Great Ice Age Owned Public Lands and Natural and Cultural Resources
U.S. Department of the Interior / U.S. Geological Survey____ As the Nation's principal conservation agency, the Department of the Interior has responsibility for most of our nationally The Great Ice Age owned public lands and natural and cultural resources. This includes fostering wise use of our land and water resources, protecting our fish and wildlife, preserving the environ mental and cultural values of our national parks and histor ical places, and providing for the enjoyment of life through outdoor recreation. The Department assesses our energy and mineral resources and works to assure that their development is in the best interests of all our people. The Department also promotes the goals of the Take Pride in America campaign by encouraging stewardship and citizen responsibility for the public lands and promoting citizen participation in their care. The Department also has a major responsibility for American Indian reservation communities and for people who live in Island Territories under U.S. Administration. Blue Glacier, Olympic National Park, Washington. The Great Ice Age land, indicating that conditions somewhat similar to those which produced the Great Ice by Louis L. Ray Age are still operating in polar and subpolar climates. The Great Ice Age, a recent chapter in the Much has been learned about the Great Ice Earth's history, was a period of recurring Age glaciers because evidence of their pres widespread glaciations. During the Pleistocene ence is so widespread and because similar Epoch of the geologic time scale, which conditions can be studied today in Greenland, began about a million or more years ago, in Antarctica, and in many mountain ranges mountain glaciers formed on all continents, where glaciers still exist. -
Terminology of Geological Time: Establishment of a Community Standard
Terminology of geological time: Establishment of a community standard Marie-Pierre Aubry1, John A. Van Couvering2, Nicholas Christie-Blick3, Ed Landing4, Brian R. Pratt5, Donald E. Owen6 and Ismael Ferrusquía-Villafranca7 1Department of Earth and Planetary Sciences, Rutgers University, Piscataway NJ 08854, USA; email: [email protected] 2Micropaleontology Press, New York, NY 10001, USA email: [email protected] 3Department of Earth and Environmental Sciences and Lamont-Doherty Earth Observatory of Columbia University, Palisades NY 10964, USA email: [email protected] 4New York State Museum, Madison Avenue, Albany NY 12230, USA email: [email protected] 5Department of Geological Sciences, University of Saskatchewan, Saskatoon SK7N 5E2, Canada; email: [email protected] 6Department of Earth and Space Sciences, Lamar University, Beaumont TX 77710 USA email: [email protected] 7Universidad Nacional Autónomo de México, Instituto de Geologia, México DF email: [email protected] ABSTRACT: It has been recommended that geological time be described in a single set of terms and according to metric or SI (“Système International d’Unités”) standards, to ensure “worldwide unification of measurement”. While any effort to improve communication in sci- entific research and writing is to be encouraged, we are also concerned that fundamental differences between date and duration, in the way that our profession expresses geological time, would be lost in such an oversimplified terminology. In addition, no precise value for ‘year’ in the SI base unit of second has been accepted by the international bodies. Under any circumstances, however, it remains the fact that geologi- cal dates – as points in time – are not relevant to the SI. -
Pleistocene - the Ice Ages
Pleistocene - the Ice Ages Sleeping Bear Dunes National Lakeshore Pleistocene - the Ice Ages • Stage is now set to understand the nature of flora and vegetation of North America and Great Lakes • Pliocene (end of Tertiary) - most genera had already originated (in palynofloras) • Flora was in place • Vegetation units (biomes) already derived Pleistocene - the Ice Ages • In the Pleistocene, earth experienced intensification towards climatic cooling • Culminated with a series of glacial- interglacial cycles • North American flora and vegetation profoundly influenced by these “ice-age” events Pleistocene - the Ice Ages What happened in the Pleistocene? 18K ya • Holocene (Recent) - the present interglacial started ~10,000 ya • Wisconsin - the last glacial (Würm in Europe) occurred between 115,000 ya - 10,000 ya • Height of Wisconsin glacial activity (most intense) was 18,000 ya - most intense towards the end of the glacial period Pleistocene - the Ice Ages What happened in the Pleistocene? • up to 100 meter drop in sea level worldwide • coastal plains become extensive • continental islands disappeared and land bridges exposed 100 m line Beringia Pleistocene - the Ice Ages What happened in the Pleistocene? • up to 100 meter drop in sea level worldwide • coastal plains become extensive • continental islands disappeared and land bridges exposed Malaysia to Asia & New Guinea and New Caledonia to Australia Present Level 100 m Level Pleistocene - the Ice Ages What happened in the Pleistocene? • up to 100 meter drop in sea level worldwide • coastal -
Glacial/Interglacial Variations in Atmospheric Carbon Dioxide
review article Glacial/interglacial variations in atmospheric carbon dioxide Daniel M. Sigman* & Edward A. Boyle² * Department of Geosciences, Guyot Hall, Princeton University, Princeton, New Jersey 08544, USA ² Department of Earth, Atmospheric, and Planetary Sciences, Room E34-258, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Massachusetts 02139, USA ............................................................................................................................................................................................................................................................................ Twenty years ago, measurements on ice cores showed that the concentration of carbon dioxide in the atmosphere was lower during ice ages than it is today. As yet, there is no broadly accepted explanation for this difference. Current investigations focus on the ocean's `biological pump', the sequestration of carbon in the ocean interior by the rain of organic carbon out of the surface ocean, and its effect on the burial of calcium carbonate in marine sediments. Some researchers surmise that the whole-ocean reservoir of algal nutrients was larger during glacial times, strengthening the biological pump at low latitudes, where these nutrients are currently limiting. Others propose that the biological pump was more ef®cient during glacial times because of more complete utilization of nutrients at high latitudes, where much of the nutrient supply currently goes unused. We present a version of the latter hypothesis that focuses on the open ocean surrounding Antarctica, involving both the biology and physics of that region. he past two million years have been characterized by of these mechanisms with data from the recent geological and large cyclic variations in climate and glaciation. During glaciological record has been a challenging and controversial task, cold `ice age' periods, large continental ice sheets cover leading as yet to no consensus on a fundamental mechanism. -
Late Glacial to Early Holocene Climate Oscillations in the American Southwest Kenneth Cole, USGS Southwest Biological Science Center Flagstaff, AZ; Ken [email protected]
Late Glacial to Early Holocene Climate Oscillations in the American Southwest Kenneth Cole, USGS Southwest Biological Science Center Flagstaff, AZ; [email protected] View of the Grand Canyon North Rim (2500 m) from a mid elevation (1500 m) on the South Rim. 1 Most of the earliest conceptions of the Pleistocene versus Holocene plant zonation consisted of lower Pleistocene zones and higher Holocene zones without much information on how they shifted from one to the other. 2 15,000 year-old packrat midden in a Grand Canyon cave. Steven’s Woodrat (Neotoma stevensii) poses with Kirsten Ironside. 3 Lower Colorado River Elevational Zonation Treeline Snowline 3000 Spruce Forest Treeline Modified From: Ponderosa Pine - Fir Forest Cole, K. L. 1990. Reconstruction Spruce Forest of past desert vegetation along the Colorado River using packrat 2000 middens. Palaeogeography, Palaeoclimatology, and Pinyon-Juniper Woodland Limber Pine, Fir Forest Palaeoecology 76: 349-366. Blackbrush - Sagebrush Juniper - Sagebrush Elevation (m) Desert Woodland 1000 Juniper - Ash Juniper - Blackbrush Brittle Bush - Woodland Woodland Creosote Bush Desert Joshua Tree - Brittle Bush - Creosote Bush Desert Sea Level Brittle Bush - Creosote Bush - Catclaw 0 5000 10000 15000 20000 Radiocarbon age (yr B.P.) K. Cole, 1995 This diagram shows a species individualistic approach made possible from plant macrofossils in packrat middens. There was still little information on the rapid Pleistocene to Holocene shift although intermediate plant assemblages were identified. 4 Carbon 13 values of packrat pellets from 92 fossil middens from the Grand Canyon, AZ Adapted From: Cole, K. L. and S. T. Arundel, 2005. Carbon 13 isotopes from fossil packrat pellets and elevational movements of Utah Agave reveal Younger Dryas cold period in Grand Canyon, Arizona.