Social Science Resource Guide 2024-2025 PDF

OUR CHANGING CLIMATE Liberty High School - Frisco, TX...

OUR CHANGING CLIMATE Liberty High School - Frisco, TX SOCIAL SCIENCE Climate Change in the Past and Present Resource Guide 2 0 24 – 2 0 25 The vision of the United States Academic Decathlon® is to provide students the opportunity to excel academically through team competition. Toll Free: 866-511-USAD (8723) Direct: 712-326-9589 Fax: 712-366-3701 Email: [email protected] Website: www.usad.org This material may not be reproduced or transmitted, in whole or in part, by any means, including but not limited to photocopy, print, electronic, or internet display (public or private sites) or downloading, without prior written permission from USAD. Violators may be prosecuted. Copyright ® 2024 by United States Academic Decathlon®. All rights reserved.  Table of Contents INTRODUCTION.................. 4 Conceptualizing Climate Change Today.............................15 SECTION I: CONCEPTUALIZING Concerns about Using the Term CLIMATE CHANGE IN THE PAST AND “Anthropocene”...................... 16 THE PRESENT..................... 5 Arguments for Using the Term Section I Introduction............... 5 “Anthropocene”...................... 17 Essential Concepts from Earth Climate Change and Narratives of System Science (ESS)............... 5 Global History..................... 17 The Earth’s Subsystems............... 6 Mapping Climate onto Existing Geosphere............................ 6 Narratives........................... 17 Liberty High School - Frisco, TX Hydrosphere.......................... 7 Climate Determinism and the Question Atmosphere.......................... 7 of Causal Relationships............... 18 Biosphere.............................. 7 Multiple Scales........................19 Forcings............................. 7 Incongruent Chronological Scales......19 Solar Energy.......................... 7 The Novelty of the Anthropocene..... 20 Volcanoes............................ 7 Section I Summary................ 20 Greenhouse Gases.................... 8 Positive and Negative Feedbacks....... 8 Examples of Positive Feedbacks........ 9 SECTION II: HUMANS IN THE Examples of Negative Feedbacks....... 9 HOLOCENE..................... 21 Section II Introduction.............. 21 Sources for Reconstructing the An Overview of the Holocene...... 23 History of Climate................. 10 The End of the Last Ice Age and the The Archives of Nature............... 10 Early Holocene...................... 23 Ice Cores............................. 10 Trees.................................. 11 The Middle Holocene................. 25 Sedimentation and Other Sources...... 11 The Late Holocene................... 25 The Archives of Society............... 11 Climate and the Development of Instrumental Records................. 12 Human Civilizations............... 26 Narrative Records..................... 12 Early Agrarian Societies.............. 27 Other Types of Records............... 13 Mesopotamia......................... 28 Fields for Studying the History of Egypt................................ 29 India................................. 29 Climate........................... 13 The Americas........................ 29 Historical Climatology and Paleoclimatology..................... 14 The Mediterranean World During Climate History...................... 14 Antiquity............................ 29 The History of Climate and Society (HCS)..15 536 CE: The Worst Year to Be Alive?..... 31 2024–2025 Social Science Resource Guide 2  The Climate in China and the Mandate of SECTION IV: RESPONDING TO THE Heaven............................. 32 CLIMATE CRISIS................. 54 The Little Ice Age (LIA) and the Section IV Introduction............ 54 Colonial World.................... 33 Recognizing the Climate Crisis..... 54 Phases of the LIA.................... 33 Research Programs................. 56 The LIA around the Globe............. 33 The World Climate Research European Empires.................... 34 Programme (WCRP).................. 57 Africa................................ 34 The International Geosphere-Biosphere Asia................................. 35 Programme (IGBP).................... 58 North America....................... 35 Raising Awareness of Climate Change 58 From the “Seventeenth-Century Crisis” to Early Public Warnings................. 59 the Nineteenth Century............... 35 The Intergovernmental Panel on Climate Change (IPCC)........................ 59 Section II Summary............... 35 Opposition to Climate Action...... 60 Nierenberg and the Marshall Institute.. 60 SECTION III: THE ANTHROPOCENE 37 U.S. Opposition to the Kyoto Protocol.... 61 Section III Introduction............. 37 Business and Industry................ 61 The Origins of the Anthropocene... 38 Political Parties..................... 63 The Industrial Revolution and the Burning News Media......................... 65 of Fossil Fuels...................... 38 Liberty High School - Frisco, TX Mitigating the Climate Crisis....... 65 The “Great Acceleration” and the Beginning Political (In)action................... 66 of the Anthropocene................. 40 The United Nations Framework Convention The Causes of the Anthropocene... 41 on Climate Change (UNFCCC)......... 66 Global Production of Greenhouse The Kyoto Protocol.................... 66 Gases.............................. 42 The Paris Agreement................. 66 The Green New Deal and the Inflation The History of Oil Extraction.......... 43 Reduction Act (IRA).................. 67 Current Sources of Fossil Fuels.......45 Historic Greenhouse Gas Emissions New Technology and Industry......... 67 in the West......................... 45 Geoengineering..................... 67 Global Greenhouse Gas Emissions.....48 New Sources of Energy.............. 68 The Consequences of the Climate Activism..................... 68 Anthropocene.................... 49 Speaking Out for “Climate Justice”..... 69 Climate Change as Part of Compounding Standing Rock and Indigenous Voices... 70 Ecological Crises.................... 50 Fridays for Future and Youth Voices.... 72 Stress on Human Habitats............ 50 Fires................................. 50 Section IV Summary.............. 73 Floods............................... 50 CONCLUSION..................... 74 Droughts............................. 51 Stress on Human Life................ 52 TIMELINE......................... 75 Health............................... 52 Financial Impacts..................... 53 GLOSSARY....................... 78 Migration............................. 53 Impending Risks.....................53 NOTES............................ 82 Section III Summary............... 53 BIBLIOGRAPHY.................... 87 2024–2025 Social Science Resource Guide 3  Introduction Can a changing climate transform humanity? questions of our lifetimes is whether or not we will Consider this fact: humans lived in an ice age for stop burning fossil fuels in time to keep the climate around 100,000 years at the end of the Pleistocene. from changing much more than it already has. While humans did migrate around the world, they left relatively little trace of their existence. Then, around This resource guide explores our changing climate 11,700 years ago, following a couple thousand years from the perspective of the social sciences. The of thawing, that ice age ended, and the Earth’s climate first section of the guide, “Conceptualizing Climate became roughly what we know it to be today. In just Change in the Past and the Present,” introduces some the past ten thousand years or so, humans have built of the tools that scientists and social scientists use to great societies; developed new technology, including understand and talk about climate change. The next writing; multiplied exponentially; and even traveled two sections are historical. Section II, “Humans in Liberty High School - Frisco, TX to the moon. Was our changing climate a factor in the Holocene,” offers a global perspective on human this remarkable transformation in how humans live? life during the years from the end of the last ice age It is difficult to say for sure. Just because two events until the nineteenth century, with an emphasis on happen one after another does not mean that the first how people interacted with the climate. Section III, event caused the second. But we can say this with “The Anthropocene,” explores how humans have confidence: humans have dramatically grown in contributed to global warming and how that warming number and capability while living in our climate since has impacted human societies. The fourth and final the end of the last ice age. section, “Responding to the Climate Crisis,” explains how people have come to recognize that humans are Today, our climate is changing again. Rather than causing climate change and examines some of the most heading back toward another ice age, however, the notable responses to this knowledge. world is getting warmer. No one knows what life will be like for our descendants if the Earth’s climate changes much more than it already has. We may be NOTE TO STUDENTS: Throughout the resource guide, currently living in a moment that turns out to be a you will notice that some terms have been boldfaced and turning point for humanity, perhaps even the end of the underlined. These terms are included in the glossary at the brief era of human growth that began less than 12,000 end of the resource guide. Also, students should be aware years ago. But unlike our ancestors who had no control that early dates in history may vary depending on the source. The dates presented in this resource guide are those dates over their changing climate, we are now the cause of provided by the sources consulted by the author in writing this our changing climate. Our practice of burning fossil guide. fuels is heating up the planet. One of the fundamental 2024–2025 Social Science Resource Guide 4  Section I Conceptualizing Climate Change in the Past and the Present SECTION I INTRODUCTION Scholars and the public use the term “climate change” to describe a complex process of changes in the natural world. But what precisely do the words “climate change” mean? In Section I of this resource guide, we will establish some key concepts that will serve as the foundation for what “climate change” means in the rest of this guide. The first set of key concepts comes from the field of Earth System Science (ESS). ESS is a relatively new Liberty High School - Frisco, TX scientific approach to studying the natural world. Its distinctive approach views the Earth’s land, oceans, and atmosphere as a single system. Rather than Depiction of the four subsystems (clockwise from top left: studying the Earth’s different parts in isolation, ESS biosphere, hydrosphere, atmosphere, geosphere) of Earth looks at the interactions between air, water, land, and System Science. living organisms. The concepts that we explore from Source: California State University Northridge, Earth Systems Interactions (csun.edu). ESS will provide a framework for understanding climate change as a natural phenomenon. Once scholars consider the Anthropocene a new geological that baseline understanding of climate change is era in planetary history in which humans have become established, we can add additional layers that consider the driving force in planetary change. The term the relationship between climate change and human “Anthropocene” references the idea that current climatic society. conditions have been heavily influenced by human The second set of key concepts describes how actions. These scholars have theorized that since around scholars create and organize our knowledge of past 1950, the world has entered a new era of climate history. climates. We will examine the sources that scholars Section I concludes with a reflection on how climate use as clues for reconstructing climate and climate change and its history relate to the ways that scholars change. Scholars in different academic disciplines use have traditionally told the story of global history. The different sources for studying the past, and they ask content of Section I offers terms and ideas that allow different questions to guide their investigations. It is for a robust conceptualization of climate change in the important to pay attention to the methods used in a past and present. field to understand the strengths and limitations of the knowledge a given field produces. A multidisciplinary approach, which incorporates the findings of more than ESSENTIAL CONCEPTS FROM one academic discipline, offers a well-rounded picture EARTH SYSTEM SCIENCE (ESS) of the history of climate change. What keeps the Earth’s climate in equilibrium? Why does the Earth’s climate sometimes change The third, and final, set of key concepts in Section so dramatically that scholars designate a period of I focuses on the idea of the Anthropocene. Many climate change? The factors that influence the climate 2024–2025 Social Science Resource Guide 5  Liberty High School - Frisco, TX Earth’s atmospheric layers. Source: WorldAtlas are varied. Moreover, the interactions between those altered from external forces. Those forces are called factors complicate the situation exponentially. Different forcings. When forcings alter the climate, it often influences mix and mingle together in a myriad of causes reactions called positive feedbacks or negative ways, producing complex outcomes that are difficult to feedbacks. These concepts will be explained in more predict or even to understand precisely. The relatively detail shortly. young field of Earth System Science puts the complex factors that shape climate and climate change into an The Earth’s Subsystems orderly system.1 While ESS offers a useful framework The Earth’s subsystems interact with each other to for scholars who study climate, the basics of ESS also influence the weather and climate. These interactions provide an easy-to-understand way for non-specialists can occur at different sized scales geographically. For to obtain an accurate, if simplified, picture of how instance, on a very large scale, an entire ocean could climate works. warm, causing changes to levels of moisture in the air over a large area. Conversely, on a small scale, a single As the name Earth System Science suggests, ESS stream might dry up, changing a local ecosystem. In conceives of the world as a single system. The system both examples, the hydrosphere is interacting with the has different parts, however, and those are called other subsystems in various ways that impact the future subsystems. On a very basic level, there are four relationship between the subsystems in those places. subsystems. The four subsystems are the geosphere (earth and rock), hydrosphere (water and ice), Geosphere atmosphere (air), and biosphere (living organisms). The geosphere encompasses all the land, earth, and These subsystems interact to shape the weather and rock that make up the planet. Sometimes, scholars use climate. The balance of the subsystems—and the the term “Lithosphere,” a word that incorporates the stability of the weather and climate—are sometimes Greek word for rock or stone, to describe the same 2024–2025 Social Science Resource Guide 6 features encompassed by the term “geosphere.” On a thermal constitution of the Earth’s subsystems. The geological time scale—encompassing the millions public is probably most familiar with the carbon cycle and billions of years it has taken for the Earth to move in which humans participate as we breathe oxygen that and change form—notable events in climate history trees and other plants produce from their absorption of include the shifting of the Earth’s plates and the carbon dioxide. In the past couple of centuries, human release and recapture of minerals and particles from use of fossil fuels has radically accelerated the Earth’s within the Earth. The Earth’s crust, a relatively thin natural carbon cycle, rapidly increasing the amount of layer of rock at the surface of the Earth, is where most carbon in the atmosphere above natural levels.2 of the interactions between the geosphere and other subsystems occur. Living organisms, which are part Forcings of the biosphere, influence the composition of the soil The Earth’s climate system—that is, the different parts itself. The geosphere also impacts weather and climate, that combine to shape the climate around the globe— as occurs in locations where mountain ranges cause involves interactions between various components of clouds to form. The eruptions of volcanoes that release the four subsystems just described. The Earth’s climate gases and particles from within the Earth also drive system is also an open system. This means that it is climate change. not entirely self-contained. Solar energy radiated from the Sun is the Earth’s vital source of external energy. Hydrosphere That energy and the Earth’s climate system mix to The hydrosphere is all the water on the Earth, in the shape climatic conditions. Despite the variability of ground, and in the atmosphere. It includes oceans weather from day to day, over longer periods, climate and freshwater rivers and lakes as well as clouds and is relatively stable. Climate, however, does change water vapor. The hydrosphere also includes ice, which slowly over time. Scientists call the specific causes of Liberty High School - Frisco, TX some scholars count as its own subsystem called the climate change forcings. There are three particularly cryosphere. Some of the most well-publicized aspects influential forcings that we will describe below: solar of current climate change focus on the hydrosphere, energy, volcanoes, and greenhouse gases. including the melting of the cryosphere at the planet’s North and South Poles, the warming of oceans and Solar Energy sea level rise, and increasingly severe droughts and Energy from the Sun heats up the Earth. Everyone flooding around the world. understands this reality from their own experience of feeling the Sun’s warmth on a clear day. But what Atmosphere we cannot intuitively experience is that the amount The atmosphere consists of various gases. On this of energy transferred from the Sun to the Earth is not basis, scholars define atmospheric zones, or layers. completely consistent over time and space. For example, They are, from lowest to highest altitude: the climatologists have identified that cooler temperatures troposphere, stratosphere, mesosphere, thermosphere, in the Northern Hemisphere in the late 1600s and early and exosphere. One important role that the atmosphere 1700s corresponded to a period of fewer sunspots and plays in climate change involves the greenhouse gas low solar activity.3 The movement of the Earth and its effect in which the concentration of certain gases relation to the Sun has been a driver of climate change released from the Earth’s other subsystems traps for hundreds of thousands of years. The Milankovitch heat in the lower layers of the atmosphere. Certain cycles reflect the fact that at intervals of around 100,000 gases in the atmosphere cause the greenhouse gas years, 41,000 years, and 26,000 years, the Earth effect because they are transparent to the Sun’s rays, completes different cycles that influence which parts allowing them to the reach the surface. When those of the Earth receive more, or less, solar energy. These rays are re-radiated by the Earth back into space, they three cycles have interacted with each other to steer the lose energy and drop to the infrared level. But at that climate of the Earth into and out of periodic ice ages.4 level, the greenhouse gases absorb them, thus trapping the heat. Volcanoes If you were outside on a hot day, you might seek Biosphere shelter from the sun by moving to a shady area. The The biosphere is all living things on, in, and around ground that has not been hit by the sun will be cooler the Earth. Life on Earth influences the chemical and than somewhere nearby that has been absorbing solar 2024–2025 Social Science Resource Guide 7  Liberty High School - Frisco, TX Volcanic gases in the atmosphere. Source: United States Geological Survey, Volcanoes Can Affect Climate | U.S. Geological Survey (usgs.gov). energy throughout the day. When large volcanoes a warming effect inside the entire car. Water vapor, erupt, they emit a layer of dust and particles that can carbon dioxide, and methane are some of the gases offer shade cover to large areas of the globe, creating that produce a greenhouse effect around the surface of cooler conditions over vast regions. When multiple the Earth. Humans release greenhouse gases into the large volcanoes erupt one after another, the cooling atmosphere through a variety of practices, contributing impact can be great enough to influence large regions to increasing concentrations of greenhouse gases in the of the world and even bring down the average global atmosphere and a more severe greenhouse effect. temperature. Positive and Negative Feedbacks Greenhouse Gases Because there are so many interconnected parts to the The term “greenhouse gases” refers to the design of Earth’s climate system, when forcings begin to change buildings called greenhouses that capture heat from the climate, the four subsystems are affected in many the Sun and are commonly used for agriculture. different ways. Reactions to climate change caused by The public probably has experienced this heating forcings are called feedbacks. Some feedbacks have dynamic more frequently in automobiles that are very already been mentioned. One is the melting of sheets hot on the inside after being parked in the sun with of ice around the North Pole. Forcings that have caused the windows up. This occurs when solar radiation climatic warming in the Northern Hemisphere have enters through the glass windows and warms up the resulted in this melting ice. interior surfaces of the car, such as the dashboard. The windows also trap the heat that radiates off the Scientists classify feedbacks as either positive or dashboard and other surfaces within the car, creating negative. In this context, “positive” and “negative” 2024–2025 Social Science Resource Guide 8  Liberty High School - Frisco, TX The greenhouse effect. Source: University of Calgary, Greenhouse effect - Energy Education. do not mean “good” and “bad.” The designation the surface of the ocean. This development alone of positive or negative refers to the relationship has harmful consequences within the biosphere by between the original forcing and the impact of the destroying the habitat of animals such as the polar feedback. If the original forcing and the feedback both bear. But the melting ice is classified as a positive push the climate in the same direction, either both feedback because the loss of ice actually warms up the warmer or both colder, then the feedback is positive. climate in addition to the initial warming. When ice So, melting polar ice sheets is a positive feedback covers the surface of the ocean, it reflects solar energy because warming caused the ice to melt, and losing back away from the surface of the Earth. The ocean the ice further warms the climate. Positive feedbacks, water that is exposed after the ice melts, conversely, therefore, keep pushing climate change in the absorbs more energy from the Sun, and the warming direction it is headed, either warmer or colder. Positive of the ocean is increased. feedbacks can push climate change to what is called a tipping point, at which time the change reaches a Examples of Negative Feedbacks point of no return. Negative feedbacks, conversely, Sometimes negative feedbacks also occur. If the serve to moderate climate change.5 initial change in climate is moving toward warmer conditions, a negative feedback would be a reaction Examples of Positive Feedbacks to warming that causes colder conditions. A smaller- Melting ice sheets around the North Pole offer a good scale negative feedback occasionally occurs during example of a positive feedback. Warmer temperatures the winter season in the Great Lakes region in in the region impact aspects of the Earth’s subsystems. North America. Warmer conditions raise the water Warmer temperatures affect the cryosphere, the ice temperature of the Great Lakes, increasing water in portion of the hydrosphere, by melting ice that is on the atmosphere. The increased water in the air over 2024–2025 Social Science Resource Guide 9  to reconstruct the actual history of climate. Like any other historical investigation, scholars need to have sources that provide evidence of past events. In standard historical practice, historians examine written sources that are collected and stored in an archive—a physical repository of documents. Scholars who study climate history have adopted the concept of an archive to describe where they find the sources they use. Sometimes, scholars who study climate also examine written documents for clues about past climatic conditions. Scholars have called the places that hold these types of sources “archives of society.” But climate scholars also search nature itself for clues about climate’s history. Scholars call these figurative storehouses of sources the “archives of nature.”6 Sections II and III of this guide will cover the history of human interactions with climate over roughly the past 10,000 years. Rather than merely recount that Lake-effect snow over the Great Lakes. history, we will now discuss how scholars have figured Source: University of Michigan, Lake-effect Snow in the Great Lakes Region | GLISA (umich.edu) out what happened. Liberty High School - Frisco, TX the lakes, in turn, becomes cloud cover that cools The Archives of Nature the surface of the Earth by blocking the sunlight. As discussed earlier, climate influences the four Additionally, the clouds formed over the lakes subsystems—earth, water, air, and living organisms— sometimes bring lake effect snowstorms, creating a in a host of different ways. Certain climatic conditions layer of snow on the ground that, like ice, serves to might correspond with specific gases in the atmosphere, reflect solar energy away from the surface of the Earth. or the growth of certain plants, or certain water levels, and so forth. Traces of those impacts are sometimes The weakening of the polar vortex is another discoverable in the natural world. In fact, nature is an possible example of a negative feedback because it archive, or a repository, of clues about how climate has recently caused colder than typical conditions in and the different parts of our world interacted in the North America. Scientists hypothesize that warmer past. Scientists and scholars have creatively developed temperatures in the oceans and atmosphere of the methods for observing and measuring signs of past Northern Hemisphere have weakened the polar vortex climatic conditions that have been preserved in different of cold air that circulates around the North Pole. As parts of the world. warmer air moves upward, the cold air in the polar vortex moves out of its usual course and travels Something observable in nature that gives an farther south into areas of the United States that it indication of past climate conditions is called a proxy. had not previously reached. In those places, winter Proxies are natural features that show evidence of temperatures drop well below regular levels. In this being impacted by specific climate conditions. If case, the initial warming causes colder conditions in scholars can isolate and date these impacts, they will some areas. Since the initial warming and subsequent have an idea of what the climate was like at a certain cooling do not align, it is a negative feedback. time in the past. Three of the most revealing sources of climate history are ice, trees, and soil.7 SOURCES FOR RECONSTRUCTING Ice Cores THE HISTORY OF CLIMATE Ice core sampling is a technique of drilling long Even if a scientist or a scholar is equipped with an cylinders of ice out of deep glaciers. The ice cores are understanding of how climate operates and how then analyzed in layers. As the ice was formed, the climate change can occur, more information is needed snowfall from each year that became the new top layer 2024–2025 Social Science Resource Guide 10  Sedimentation and Other Sources Scholars also study other parts of the natural world for data that has been collected about past conditions. The layers of sediment or mud on the bottom of lakes and the ocean contain information about the historical composition and content of water such as the amount of pollen. Coral sampling in the ocean reveals similar data as well as past temperatures of the ocean in the location of the coral. Scientists creatively harvest data about the impact of past climate conditions on various parts of the Earth System and its subsystems. Through such discoveries, scholars rediscover the climate of the past. The Archives of Society Ice core sample. There is also evidence of past climate conditions in Source: National Science Foundation, About Ice Cores | NSF Ice Core the archives of society. The term archives of society Facility refers to sources produced by humans that contain information about the climate. There are some obvious of the glacier would trap particles from the atmosphere limitations to the information scholars can gain from and freeze them in the ice. Therefore, an ice core the archives of society. Human records only describe from an old glacier can reveal what the atmospheric conditions over the past hundreds or thousands of Liberty High School - Frisco, TX conditions were dating as far back as hundreds of years, not the past millions of years that some sources thousands of years.8 from the archives of nature reveal. Additionally, the most precise information from the archives of Trees society, instrumental records such as recordings of Trees can also be analyzed for information about past temperature, are an even newer development. The climates. One can identify the age of a tree by counting oldest instrumental records date back only to the the rings of a tree that has been cut through. Scientists thermometer’s invention around 1700. know how to analyze each of those rings for information about the weather during that year of the tree’s life. The However, even before humans had modern scientific tree can reveal if the year was dry or rainy and can even instruments, they left records that describe the climate. show the weather conditions of individual seasons in a To make use of these records, scholars utilize a system year. The practice of gathering this information from of proxies similar to those used to study the archive of trees is called dendrochronology—a combination of nature. While proxies produce less precise information words that refer to trees and time. Temperature reconstruction and tree ring sample. Source: University of Georgia, New tree ring data set shows NH temperatures | Climate and Agriculture in the Southeast (uga.edu) 2024–2025 Social Science Resource Guide 11  Liberty High School - Frisco, TX An unused German calendar printed in 1594 with space for users to record weather conditions. Source: Bayerische StaatsBibliothek A French thermometer from around 1780. Source: Whipple Museum of the History of Science, collections. of time. For example, Phoenix, Arizona, received whipplemuseum.cam.ac.uk/objects/11165/ attention in the news for record-breaking heat in the summer of 2023. But temperature records for the than a reading from a scientific instrument, they can still city of Phoenix only date back to the year 1896.9 So, produce reliable information. For instance, a narrative instrumental records can clearly show trends in the account of a flood in the 1500s will not contain an exact climate, but only for a little more than a century. measurement of how much rain fell, but scholars can reliably know that substantial rainfall did occur. One Additionally, scholars are constantly thinking about area in which the archives of society are more specific where and how measurements should be taken to get than the archives of nature is in dating. From tree the clearest possible picture of what the climate is records we may know that there was a good year of rain doing. For instance, scientists record the temperature for plant growth, but human records can give details at different layers of the atmosphere to gain a more down to the day or hour of when it rained. precise understanding of climate trends above the Earth.10 Even though data on things like precipitation Instrumental Records and temperature taken from reliable scientific Scholars use precise and accurate information that instruments seems straightforward, careful analysis was recorded by scientific instruments to identify is still required to combine points of data from many trends in the climate. Today, meteorologists measure individual places at specific moments in time into an daily records of high and low temperatures from accurate understanding of climate trends over larger many places around the globe. These records are very areas and longer timespans. precise, but they only go back a relatively short period 2024–2025 Social Science Resource Guide 12  Hendrick Avercamp, Winter Landscape with Skaters, c. 1608. An eighteenth-century depiction of the Swiss town of Source: Rijksmuseum Grindelwald and a nearby glacier. Source: Swiss National Library Other Types of Records There are a variety of other types of records that Narrative Records people have left behind that also contain clues about Even before people had the instruments to past weather and climate. Sometimes people made systematically record temperature and precipitation, a marker of a highwater mark during a flood that they still paid attention to the weather and other one can see on a building. Works of art also show climate-related developments. Scholars can examine depictions of weather conditions. Scholars need to Liberty High School - Frisco, TX human-produced records for clues about past climate be careful, however, to consider if the proxy they are conditions. These types of sources include weather using accurately reflects real conditions. A painting is diaries in which someone might have left short daily not the same as a photograph with a date. The artist entries that document if it was hot, cold, rainy, cloudy, may be depicting a real scene, or the inspiration for the sunny, and so on. Ship logbooks often include such painting may have come from elsewhere. information. Other narrative records might describe whether a glacier is growing or receding, how high Grain prices are another proxy that scholars have the water level is in a river or lake, whether a lake is used as a marker for weather conditions. There is frozen or not, or detailed descriptions of exceptional a correlation between certain types of weather and occurrences, such as a long drought or a severe storm. fruitful harvests that would cause prices to decline. Recently, however, some scholars have argued that too Scholars treat the information contained in narrative many other factors, unrelated to weather, might also records as proxies for estimating the information drive grain prices up or down, and that prices do not that modern scientific instruments can record such accurately reflect weather conditions. Debating how to as temperature, rainfall, or snowfall. Although use sources is a healthy part of scientific inquiry and the narrative records do not contain a temperature leads to more refined and reliable methods for studying recording, if they do contain an account of a cold past climate conditions. winter and describe a frozen river, for instance, scholars can devise systems for taking those records and comparing them with other records to gain an idea FIELDS FOR STUDYING THE of climate trends and conditions over time. To return HISTORY OF CLIMATE to the glacier example, accounts of glacier expansion Because there are many different types of sources are not the same as temperature readings that show that contain information about the history of climate, an average temperature decline, but the growth of the different scholars have focused on becoming experts glacier works as a proxy to suggest that it is growing at analyzing specific types of sources. Professionally because temperatures are declining. trained scientists, social scientists, and historians are all highly specialized. That means a scholar will likely 2024–2025 Social Science Resource Guide 13 only have expertise in researching climate history in a particular way. Sometimes, when a scholar identifies sources that contain useful information and develops effective methods for analyzing those sources, other scholars begin to join the work, and a new scholarly field is born. A scholarly field, in other words, consists of a group of scholars who share common practices for studying the type of evidence they analyze. Usually, a scholar is primarily a member of one field. Different scholarly fields use different means to study the history of climate. Often, findings about climate history do not perfectly align within a given field, or between fields. Having robust fields with many scholars and lots of research provides many perspectives and the opportunity to reflect on which studies produce the most accurate results. Comparing discoveries that have been made between different fields allows for an outside check on the findings made within a field. Every scholarly field also has its own strengths and Christian Pfister led the creation of the field of climate history. limitations. The existence of multiple fields that examine climate history offers us an opportunity to learn from Liberty High School - Frisco, TX many skills, including, but not limited to: collecting the strengths of different fields and move beyond the samples from nature (such as ice cores or tree samples), limits of each individual field. Overall, the fields of operating the machinery or instruments used to analyze historical climatology, paleoclimatology, climate the samples, analyzing the data obtained from nature to history, and the history of climate and society (HCS) reconstruct past climate conditions, and communicating offer complementary views of climate history. Together, findings from nature according to the standard written they present a reliable picture of past climate and its conventions of the field of climatology. relationship to human life. Climate History Historical Climatology and The field of climate history, by comparison, utilizes a Paleoclimatology different set of practices to analyze different sources. Historical climatology and paleoclimatology are Climate historians collect and study sources from the different names for essentially the same field. Both archives of society, and they analyze those sources terms end with the word “climatology” prefaced by according to historians’ methods and conventions. either “historical” or “paleo-.” Climatology is a study The skills that climate historians bring to the study of of climate that relies primarily on the archives of climate include: the ability to read the language and nature. That is, climatologists are experts at gathering script of the texts being analyzed; the ability to find information about climate from the investigation of the the texts, analytical techniques, and the contextual natural world, including the sources described earlier, knowledge to interpret the texts accurately; and the such as layers of ice or lake sediment or tree rings. ability to formulate and communicate historical The term “paleo-” means ancient or old and conveys narratives based on the textual evidence. The Swiss a similar idea as the term “historical” in this context. historian Christian Pfister (b. 1944) was an influential Historical climatology or paleoclimatology investigates pioneer in the field of climate history and diligently climates of the past, particularly before the 1800s when compiled sources and developed methodological scholars first utilized existing scientific instruments approaches to analyze them. He compellingly for the purpose of creating widespread and systematic demonstrated that sources in the archives of society can records of climatic conditions. be used to produce trustworthy climate reconstructions. Historical climatologists must learn and practice A climate historian, therefore, looks in different places 2024–2025 Social Science Resource Guide 14  Time scale ratified by the International Union of Geological Sciences (IUGS). Abbreviations: “b2k” = before the year 2000; ka = thousands of years before present; Ma = millions of years before present. Source: Subcommission on Quaternary Stratigraphy, Major divisions | Subcommission on Quaternary Stratigraphy than the historical climatologist for information about one’s investigation. For instance, different levels of past climate conditions. A scholar in one field would geographical scale could be a city, a large region, likely not have the training and expertise to accurately a continent, or the entire globe. Different levels of analyze the types of sources that someone in the other chronological scale could be days, decades, millennia, Liberty High School - Frisco, TX field does. The fields complement each other, however, or millions of years. because they broadly explore the same topic from different perspectives. HCS emphasizes the significance of precision when it comes to scale. If a scholar only has sources from The History of Climate and Society (HCS) one town, that evidence may not support a claim about The history of climate and society (HCS) is a new an entire region. Or if the sources are all from a few field that is just beginning to emerge. Environmental decades, that data may not support a claim about entire historian Dagomar Degroot has led the push to form centuries. Geographical scale and chronological scale and name the field of HCS. The need for the field, are very important for the study of climate history and according to scholars within it, has stemmed from the its relationship to human life. recent expansion of studies on climate from a variety of fields including climate history and paleoclimatology, CONCEPTUALIZING CLIMATE as well as other fields such as archeology, economics, CHANGE TODAY geography, linguistics, and genetics. As its name Historians always study the past from the context of suggests, the field of HCS focuses on the relationship their own time. Historians try to be self-aware and between past climate conditions and human societies. consider potential biases from the present that might taint their understanding of the past. The relationship At that intersection of climate and society, HCS between present climate change and past climate scholars contend that existing research from the various change, however, offers a particularly tricky challenge fields just listed often lacks precision. Specifically, for scholars. On the one hand, there is a lot of continuity HCS scrutinizes scholarly claims about climate’s past between the past and the present in terms of how the impacts on human society. HCS seeks to apply rigorous Earth’s subsystems interact to create climate conditions. analytical methods from the field of history to make Studying past climate change can help scientists and sure that sufficient evidence exists to support claims scholars understand what causes change and how the about climate causing certain social conditions. To put it Earth reacts to forcings that cause climate change. simply, HCS scrutinizes causal claims.11 On the other hand, the primary cause of current global The field of HCS also pays careful attention to warming—humans releasing greenhouse gases into scale. In this context, scale refers to the scope of the atmosphere—is unprecedented in human and 2024–2025 Social Science Resource Guide 15  Liberty High School - Frisco, TX Though the Anthropocene Working Group (AWG) has proposed that the Anthropocene should officially be recognized as a new geological time interval, their proposal was not officially accepted. global history. Starting about two hundred years ago epoch prior to the Holocene, the Pleistocene, started and increasingly since then, people have extracted and around 2.58 million years ago. The use of the term released fossil fuels at unprecedented levels. So, there “Anthropocene” to refer to the era we live in today are also strong discontinuities between climate change suggests that the climate change we are experiencing today and climate change in the distant, and not-so- at present is so significant that it is comparable to distant, past. epochs of very substantial climate change in the past. The inclusion of the prefix “Anthro-” at the beginning What concepts should scholars use to describe the of the term strongly emphasizes that humans have relationship between today’s climate change and primarily contributed to the current trajectory of the climate change in a broader chronological context? climate. One answer to this question has come in the form of a term used to describe climate change today: the Concerns about Using the Term Anthropocene.12 The term Anthropocene puts current “Anthropocene” climate conditions into the broader context of climate The stakes are high for adopting the term Anthropocene, history while also placing a strong emphasis on the and some scholars have reservations about doing so. In uniqueness of today’s climate. science, systems of classification are very consequential The concept of the Anthropocene refers to the as these systems organize human knowledge. scientific divisions of geological time that correspond Accordingly, scholars and scientists take them very to climatic conditions of the Earth over millions of seriously. Do scientists really know enough about years through to the present. The current era, or epoch, climate change today to decide that it is on the same is the Holocene, which started around 11.7 thousand level as the transitions into and out of the Pleistocene years ago, at the end of the last global ice age. The and into the Holocene? That question is currently being 2024–2025 Social Science Resource Guide 16 debated by scientists in the geological community. In have been telling stories about global history since 2019, the Anthropocene Working Group (AWG), a body the modern historical profession became formalized of experts on the Earth’s geological epochs, proposed in Europe in the 1800s. But with a few exceptions, that the Anthropocene should officially be recognized such as the French historians E. Le Roy Ladurie as a new geological time interval. They advocated that and Fernand Braudel, modern historians did not starting in the mid twentieth century, around 1950, include climate in their narratives of global history the Holocene ended, and the Anthropocene began. In until around the year 2000. Because climate was not March of 2024, the International Union of Geological included in traditional histories of the world before Sciences rejected a proposal to formally name the the past two and a half decades, many things have Anthropocene as a new geological epoch, but noted that converged—or crashed together at once—since the term will “continue to be used not only by Earth and historians have started trying to incorporate climate environmental scientists but also by social scientists, into the story of world history. Historians and scientists politicians and economists as well as by the public at are still sorting out the combined story of climate large” and “will remain an invaluable descriptor of history and human history. human impact on the Earth system.”13 According to the formal geological time scale accepted by the geological Just as scholars in scientific fields constantly revise community, we still live in the Holocene.14 their conclusions and make them more precise and accurate when new information becomes available, Arguments for Using the Term historians also revise the stories they tell when new information becomes available. This process has “Anthropocene” been very evident as scholars have tried a variety of Is it useful and appropriate to use the term approaches to integrating climate history and human Liberty High School - Frisco, TX Anthropocene even if scholars in the geological history. The dynamic, and ongoing, process in which community who could make the term official have historians are trying to understand the role that climate not done so? It is, for several reasons. Putting the has played in past civilizations and how that history Anthropocene in the official geological time scale is relates to the present is both fascinating and important. a very high bar to reach. The fact that geologists are careful before taking such a dramatic step reflects the Mapping Climate onto Existing Narratives seriousness of scientists. The idea of the Anthropocene One, perhaps obvious, approach to bringing together is not discredited because it has not received that existing historical narratives and new information specific recognition. about climate history is to simply place the two An important reason to use the term Anthropocene histories over one another. Historians have well- is that other scholars and the public often refer to the established narratives about most parts of the world. Anthropocene already. The evidence overwhelmingly Often, these narratives divide history into a series of suggests that 1950 is an appropriate marker for the stages that are marked by political developments. The start of current warming trends in the climate. While history of China over the past several thousand years, scholars are debating the nuances of whether or not for instance, can be portrayed neatly as a timeline of the mid-twentieth century qualifies as an epochal successive dynasties: Xia, Shang, Zhou, Qin, Han, change on the scale of the Holocene, something and so forth. For the Mediterranean World, a popular drastic is taking place in today’s climate. The term narrative moves from the Greek Empire to the Roman Anthropocene has become a way to name what is Empire to the Middle Ages and so on. happening, making it easier for scholars, journalists, One option for combining climate history with these and members of the public to have vitally important types of existing historical narratives is to look at conversations about our changing climate.15 notable junctures, such as the transition from one dynasty to another, and then see if any climatic CLIMATE CHANGE AND events—such as a period of climate change—occurred NARRATIVES OF GLOBAL HISTORY around the same period. Often, scholars who employ Humans have been telling narratives, or stories, about this technique are able to show striking correlations global history for millennia. Professional historians between large-scale social events, such as mass revolts 2024–2025 Social Science Resource Guide 17  Liberty High School - Frisco, TX Correlations between climatic conditions and human history. Source: “Climate in Human History” in Donald R. Prothero and Robert H. Dott, Evolution of the Earth, 8th ed, McGraw-Hill, 2010. in a region, and climate-related conditions, like an to causation. In other words, it is hard to determine if extended period of drought. The climate events and one event in history caused a second event, or if they the social events often line up to such a degree that it just coincidentally happened. Often, there is not enough seems to be more than a mere coincidence. evidence to prove the causal relationship definitively or with certainty. So, historians need to use careful A potential weakness of this approach, however, is reasoning to offer an interpretation of the available that it is not the best practice in history or science for evidence that suggests why and how something might scholars to desire to prove too specific of a thesis before have caused something else.16 they begin to study their sources. This is because such an approach could lead to biases in the results. In the context of the history of climate and society, a Sometimes, scholars might find what they are looking major question is whether or how climate conditions for, but miss other important observations. Using cause events in human societies. Do favorable climate existing narratives to guide the study of climate history conditions cause an empire to thrive? Do unfavorable may put too many constraints on climate history and conditions cause revolts and revolutions? Older turn it into little more than the retelling of narratives that scholarship—including some of the pioneering works are still based on the old frameworks they were always of history that first gave attention to climate history based on, such as dynasties or empires. as a factor in human history—made the case that climate determined or dictated the course of human Climate Determinism and the Question history. More recent studies have cast doubt on such of Causal Relationships a strong link between climate and the development Attempts to combine climate history and human history of human culture and society. Recently, the argument have also raised challenging interpretive issues related that climate sets the course for human history has been 2024–2025 Social Science Resource Guide 18 labeled climate determinism. Almost all studies of climate and society today say that they are rejecting climate determinism, but some scholars still argue that climate played a major role in shaping human history. Scholars may be able to show a correlation between a certain climatic condition and a human event, but that does not actually prove that the first one caused the second one. In the field of the history of climate and society, scholars place emphasis on the careful study and analysis of causal mechanisms. This approach asks what specifically did the climate impact that then became the exact thing that triggered a human response. Those gears that turn and then make the next gears turn are the causal mechanisms that could offer a more intricate explanation of how climate has affected human behavior and societies.17 Multiple Scales Another major challenge for combining human climate history and human history relates to the matter of scale. Typically, the chronological scale Liberty High School - Frisco, TX of human histories dates back to around five or six thousand years ago when the first major human societies emerged. These civilizations in places like Ancient Mesopotamia, Egypt, and China have left robust traces of buildings, artifacts, and even written documents that allow historians to reconstruct their histories. Sometimes, scholars use archeological Rachel Carson in 1960. evidence to create historical accounts of what human Source: https://www.rachelcarson.org/ life was like as far back as around 40,000 years ago. Most often, historical studies focus on human events in the much more recent past, such as the twentieth Because humans before the twentieth century did century. However, a few thousand years of human not have the capability to impact climate on the scale history amount to little more than a blink of an eye that humans do today, humans arguably lacked an when compared to the millions of years over which the awareness that their actions even had the potential to Earth’s climate has evolved to become what it is today. shape the world in such a forceful and lasting way. In what meaningful way can scholars compare these Although she was not writing about climate, Rachel two vastly different chronological scales? Carson (1907−64), with her 1962 book Silent Spring, is often credited with helping humans develop an In the past, scholarly fields that study the science of awareness of how much potential we now have to alter climate change and scholarly fields that study human the Earth. Her book compellingly demonstrated how histories did not overlap. The current state of climate commercial pesticides destroyed living organisms change caused by human behavior—known as the and radically transformed ecosystems in mere years, Anthropocene—has brought these two histories whereas natural changes in an ecosystem could only together at the moment in time in which we currently evolve over the course of decades or generations. live. Scholars are in the process of figuring out how to tell the story of the Earth’s history and the story of Today, scholars such as Dipesh Chakrabarty argue that human history in a way that illuminates both histories. humans are reshaping the configuration of the Earth’s climate systems in a timespan that is exponentially Incongruent Chronological Scales shorter than natural processes.18 Today’s climate 2024–2025 Social Science Resource Guide 19 change, therefore, is an event that takes place on the variations in solar energy reaching the Earth, small scale of human history because humans are a and rising concentrations of greenhouse leading cause of the climate change. But the changes gases in the atmosphere—can tip the balance are also so substantial that they have become part of between subsystems and cause climate change. the story of the Earth’s climate that has developed over Sometimes, climate change causes reactions 6 a much greater scale (millions of years). Thus, while in nature that drive the change even more these two chronological scales are incongruent, they (positive feedbacks), while other times nevertheless have now intersected in our lifetime. reactions in nature act against the initial drivers of climate change (negative feedbacks). The Novelty of the Anthropocene The novelty, or newness, of the Anthropocene presents 6 Scholars and scientists learn about climate the social science scholar and the social science student history by investigating evidence in the natural with unprecedented challenges. Old methods and old world (archives of nature) and in records left by narratives in the field of history must now account for humans (archives of society). new discoveries from fields that examine climatology. 6 Historical climatologists and Scholars and the public wonder if anything from paleoclimatologists study the archives of history relates to the Anthropocene and if there are nature. Climate historians study the archives any lessons from the past that can guide us through of society. Scholars in the field of the history the challenges of the multiple natural crises that of climate and society (HCS) focus on the humanity now faces. These are real challenges, but relationship between climate history and they also offer exciting new opportunities. The project human history. Liberty High School - Frisco, TX of uncovering and sharing the combined history of 6 The Anthropocene is a term that scholars climate and humanity is already allowing us to see and the public have begun using to describe ourselves and our world in new ways. the idea that current climate change might mark the beginning of a new climatic and SECTION I SUMMARY geological epoch in the Earth’s history. The 6 The field of Earth System Science (ESS) term Anthropocene also reflects the reality that provides key concepts for understanding the current climate change is significantly caused nature of the Earth’s climate and climate by human actions. change. 6 It is a challenge to combine climate history 6 The Earth’s four subsystems—earth, water, air, and human history into a single story, but by and living organisms—interact on local and attempting to do so, historians help us better global levels to shape climatic conditions. understand our changing climate. 6 Forcings—events such as volcanic eruptions, 2024–2025 Social Science Resource Guide 20  Section II Humans in the Holocene Liberty High School - Frisco, TX Map of Northern Hemisphere ice sheets, glaciers, and permafrost during the Last Glacial Maximum. Source: Amelie Lindgren, et al, “GIS-based Maps and Area Estimates of Northern Hemisphere Permafrost Extent during the Last Glacial Maximum,” Permafrost and Periglacial Processes 27 (2015). SECTION II INTRODUCTION record of Homo sapiens around 300,000 years ago According to the International Union of Geological or to around 40,000 years ago when Homo sapiens Sciences (IUGS), the geological and climatic epoch became the last surviving members of the Homo known as the Holocene began about 11,700 years ago.19 genus, humans had a much longer history on Earth During the Holocene, humans have thrived like never before the start of the Holocene than we have had since before. Whether one dates back to the oldest fossil it began.20 But our species never came close to building what humans have built during the Holocene. Before 2024–2025 Social Science Resource Guide 21  The climate of Europe during the Last Glacial Maximum. European Geosciences Union. Cryospheric Sciences | Image of the Week — Last Glacial Maximum in Europe (egu.eu) Liberty High School - Frisco, TX the Holocene, the global human population may not Holocene was very different than the environment we have surpassed ten million.21 According to the United have known since. Most of human history took place Nations, the current global human population is over in the Pleistocene Epoch (2.6 million years ago to eight billion.22 Traces of human manufacturing and 11,700 years ago), a period characterized by cycles of other activities that impact the environment can be glaciers growing or receding and, at times, covering found nearly everywhere on the planet.23 vast portions of the Earth’s surface. The Last Glacial Maximum (LGM) occurred around 20,000 years ago. Climate and environment do not determine the course At that time, much of what is known today as Europe, of human development and history. That said, there including Scandinavia, the British Isles, and parts of are many, many climatic conditions in which humans Central Europe, were covered by ice. Much of North could not survive, let alone thrive. The specific course America was as well. Asia experienced permafrost— of human history over the past 12,000 years is not the perennially frozen ground.24 inevitable outcome of human life in the Holocene. Climate did not determine the twists and turns of So much of the world’s water was frozen on the the human story, nor did it dictate that humanity Earth’s surface that ocean levels were hundreds of would be standing where we are today. Yet, it is also feet lower than current levels. Since the LGM, that undeniable that the Holocene has been the historical ice has receded and melted into the ocean, but not setting in which humans grew to become the global evenly over time. Warming caused by solar cycles force we are now. Humans have not flourished in a contributed to a major glacial meltwater event that vacuum completely on our own. Humans have thrived started around 14,000 years ago and, in turn, cooled under very specific environmental conditions—the ocean temperatures and reversed warming trends for conditions of the Holocene. At a minimum, one must roughly a millennium. That cold millennium is known know what the Holocene is to be aware of the stage on as the Younger Dryas period (c. 12,900 to 11,700 years which the human drama has played out. ago). Since its conclusion, the world resumed warming in a new epoch known as the Holocene. The general marker of the start of the Holocene, roughly 11,700 years ago, is the end of the last ice Technically, the Holocene is an interglacial period—a age. The world that humans lived in prior to the warm period between ice ages—that follows a much 2024–2025 Social Science Resource Guide 22  The subdivision of the Holocene Series/Epoch. Mike Walker, Martin J. Head, John Lowe, Max Berkelhammer, Svante Björck, et al, “Subdividing the Holocene Series/Epoch: formalization of stages/ages and subseries/subepochs, and designation of GSSPs and auxiliary stratotypes,” Journal of Quaternary Science 34 (2019): 174. longer pattern throughout the Quaternary Period of ice growing and receding in cycles. The Quaternary Period is a unit of geologic time that began 2.6 million years ago and consists of both the Pleistocene and the Holocene.25 In the last 800,000 years, there have been eight similar interglacials. Patterns in the Earth’s orbit, known as the Milankovitch cycles, affect the amount of solar energy the Earth absorbs at different times. The differences in solar energy over time have Liberty High School - Frisco, TX been the dominant forcing that moves the climate back and forth between ice ages and interglacial warm periods.26 According to the factors that had dominated the Earth’s climate over the past 2.6 million years, the Earth would likely be cooling right now. Instead, the planet is rapidly warming. That phenomenon will be the subject of section III of this resource guide. AN OVERVIEW OF THE HOLOCENE Scholars divide the Holocene into three periods. The three periods are dated according to how many years ago they started and ended, with the year 2000 ce marking the present. The first period lasted from 11,700 to 8,236 years ago and is named the Early Holocene Subseries/Subepoch or the Greenlandian Stage/Age. The second period dates from 8,236 to 4,250 years ago and is known as the Middle Holocene Subseries/ Location of NGRIP2 ice core sample, indicated in bold font. Subepoch or the Northgrippian Stage/Age. The third, Mike Walker, Martin J. Head, John Lowe, Max Berkelhammer, Svante and final, period runs from 4,250 years ago to the Björck, et al, “Subdividing the Holocene Series/Epoch: formalization of stages/ages and subseries/subepochs, and designation of GSSPs and auxiliary present and is known as the Late Holocene Subseries/ stratotypes,” Journal of Quaternary Science 34 (2019): 176. Subepoch or the Meghalayan Stage/Age. Each of these three periods are described in more detail below.27 from around 11,000 to 7,000 years ago. The ending date of the Early Holocene coincides with a meltwater The End of the Last Ice Age and the event in Canada when a glacial ice sheet collapsed. The Early Holocene classification of the Early Holocene as the Greenlandian The Early Holocene lasted from around 11,700 to 8,236 Stage/Age refers to the ice core in Greenland, NGRIP2, years ago. It occurred during part of the warmest period which bears evidence of the onset of the Holocene at a of the Holocene—the Holocene thermal maximum depth of 1,492.45 meters into the ice. 2024–2025 Social Science Resource Guide 23  Liberty High School - Frisco, TX Peopling of global regions in the last 100,000 years. Numbers indicate thousands of years (ky) before present (BP). Graph on bottom shows proxy indicator of warm and cold periods. Franz Mauelshagen, “Migration and Climate in World History,” 415. By the start of the Holocene, humans had already extinction. Other scholars point to a lack of evidence migrated out of Africa across Eurasia to the east and for that hypothesis and suggest that the animals’ west, to Australia, and to the Americas from the north decline was the result of their own inability to adapt to to the south.28 In other words, humans were already a changing climate.30 all over the globe. Therefore, the question of how the transition from the Pleistocene to the Holocene These few examples highlight that climate change intersected with human life must be answered at was not the same everywhere on the globe, and the local level because no two places in the world even in a specific location, the interactions between are identical. New research has investigated human climate, nature, and humans were complex. Local practices during the Early Holocene in the Iberian environmental conditions and factors that are unique to Peninsula at the western edge of Europe and in individual human communities make it necessary for Madagascar off the east coast of Africa, to take two scholars and scientists to study specific geographical examples.29 In North America, the beginning of the regions in depth. Generalizations have limited Holocene appears to coincide with the extinction of accuracy. Broadly speaking, though, during the Early dozens of large mammals. One popular explanation Holocene humans still largely hunted and maintained for their disappearance is that humans adapting to the mobile communities. Agricultural practices— new conditions of the Early Holocene hunted them to including staple crop production in the Americas— increased, but the large agricultural societies typically 2024–2025 Social Science Resource Guide 24  Bronze axe heads from third millenium bce Mesopotamia. Source: The Sulaimaniya Museum, Iraq The retreat of the Laurentide Ice Sheet over the past 18,000 Years. humans began utilizing metal instruments in new Dyke, A.S. (2009). Laurentide Ice Sheet. In: Gornitz, V. (eds) Encyclopedia of Paleoclimatology and Ancient Environments. Encyclopedia of Earth ways. Larger and more socially stratified agricultural Sciences Series. Springer, Dordrecht. societies also emerged, including, most notably, the Mesopotamian civilization around 5,500 years counted as the first of their kind in human