2024-2025 Social Science Pentathlon Resource Guide (PDF)

Introduction Can a changing climate transform humanity? Consider the planet. One fundamental question of our lifetime is this fact: humans spent thousands of years living in an whether or not we will stop burning fossil fuels in time ice age cal...

Introduction Can a changing climate transform humanity? Consider the planet. One fundamental question of our lifetime is this fact: humans spent thousands of years living in an whether or not we will stop burning fossil fuels in time ice age called the Pleistocene era. While humans did to keep the climate from changing much more than it migrate around the world, they left relatively little trace already has. of their existence. Around 11,700 years ago, after a few thousand years of melting, the ice age ended, and the This resource guide explores our changing climate Earth’s weather became pretty much like it is now. In from the perspective of the social sciences. The just the past ten thousand years or so, humans have built first section of the guide, “Conceptualizing Climate great societies; developed new technology, and even Change in the Past and the Present,” introduces some traveled to the moon. Was our changing climate a factor of the tools that scientists and social scientists use to in this remarkable transformation in how humans live? understand and talk about climate change. The next We can’t know for sure. Just because two events happen two sections are historical. Section II, “Humans in Texas Pentathlon - TX, TX one after another does not mean that the first event the Holocene,” offers a global perspective on human caused the second. But we do know that human societies life during the years from the end of the last ice age have significantly grown in number and capability since until the nineteenth century, with an emphasis on the last ice age. how people interacted with the climate. Section III, “The Anthropocene,” explores how humans have Today, our climate is changing again. Instead of contributed to global warming and how that warming heading back toward another ice age, the world is has impacted human societies. The fourth and final getting warmer. No one knows what life will be like section, “Responding to the Climate Crisis,” explains for our descendants if the Earth’s climate changes how people have come to recognize that humans are much more than it already has. We may be living in causing climate change and examines some of the most a moment that becomes a turning point for humanity, notable responses to this knowledge. perhaps even the end of the brief era of human growth NOTE TO STUDENTS: Throughout the resource guide, you will that began less than 12,000 years ago. But unlike our notice that some terms have been boldfaced and underlined. ancestors who had no control over their changing These terms are included in the glossary at the end of the climate, we are now the cause of our changing climate. resource guide. Also, students should be aware that early Electricity, heat and transportation all use fossil fuels dates in history may vary depending on the source. The dates like oil or coal. Burning these fossil fuels is heating up presented in this resource guide are those dates provided by the sources consulted by the author in writing this guide. 2024–2025 Social Science Pentathlon 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 exactly 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 scientific approach to studying the natural world. Its Texas Pentathlon - TX, TX distinctive approach looks at 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 one at a time, ESS biosphere, hydrosphere, atmosphere, geosphere) of Earth looks at the interactions between air, water, land, and System Science. living organisms. The ideas that we learn from ESS Source: California State University Northridge, Earth Systems Interactions (csun.edu). will help us understand climate change as a natural part of our world. Once that baseline understanding of humans have become the driving force in the way our climate change is established, we can add additional planet is changing. The term “Anthropocene” references layers that consider the relationship between climate the idea that current climatic conditions have been change and human society. heavily impacted by human actions. These scholars have The second set of key concepts describes how scholars theorized that since around 1950, the world has entered create and organize our knowledge of past climates. We a new era of climate history. will examine the sources that scholars use as clues for Section I concludes with a reflection on how climate reconstructing climate and climate change. Scholars change and its history relate to the ways that scholars in different academic disciplines use different sources have traditionally told the story of global history. The for studying the past, and they ask different questions content of Section I offers terms and ideas that allow to guide their investigations. It is important to pay for an understanding of climate change in the past and attention to the methods used in a particular field. This present. can help people understand the strengths and limitations of the knowledge a given field produces. Using a multidisciplinary approach, which combines research ESSENTIAL CONCEPTS FROM from different academic fields, gives us a more complete EARTH SYSTEM SCIENCE (ESS) picture of the history of climate change. What keeps the Earth’s climate in balance? Why does the Earth’s climate sometimes change so dramatically The third, and final, set of key concepts in Section I that scholars designate a period of climate change? focuses on the idea of the Anthropocene. Many scholars The factors that influence the climate are varied. consider the Anthropocene a new geological era where In addition, the interactions between those factors 2024–2025 Social Science Pentathlon Resource Guide 5  Texas Pentathlon - TX, TX Earth’s atmospheric layers. Source: WorldAtlas complicate the situation. Different influences interact The Earth’s Subsystems in unpredictable ways, creating complex results that The Earth’s subsystems interact with each other to are hard to predict or clearly understand. The relatively influence the weather and climate. These interactions young field of Earth System Science puts the complex can occur on very different geographical scales. For factors that shape climate and climate change into an instance, on a very large scale, an entire ocean could orderly system.1 While ESS offers a useful framework warm, causing changes to levels of moisture in the air for scholars who study climate, the basics of ESS also over a large area. On a small scale, a single stream might provide an easy-to-understand way for non-specialists dry up, changing a local ecosystem. In both examples, to obtain an accurate, if simplified, picture of how the hydrosphere is interacting with the Earth’s other climate works. subsystems in different ways that impact the future relationship between the subsystems in those places. As the name Earth System Science suggests, ESS thinks of the world as a single system. This is broken Geosphere into different parts called subsystems. On a very basic The geosphere includes all the land, earth, and rock that level, there are four subsystems: the geosphere (earth make up the planet. Sometimes, scholars use the term and rock), hydrosphere (water and ice), atmosphere “Lithosphere,” a word that incorporates the Greek word (air), and biosphere (living organisms). These for rock or stone, to describe the same features covered subsystems interact to shape the weather and climate. by the term “geosphere.” A geological time scale, Sometimes, external forces, called forcings, alter the which can encompass the millions and billions of years stability of the weather and the climate. When forcings it has taken for the Earth to move and change form. One alter the climate, they can cause reactions called either notable event in climate history includes the shifting positive feedbacks or negative feedbacks. These of the Earth’s plates. Plate tectonics created mountains, concepts will be explained in more detail shortly. volcanoes and oceans. Another notable event involves 2024–2025 Social Science Pentathlon Resource Guide 6 volcanic eruptions, which have produced enough gases plants through their absorption of carbon dioxide. In and particles to create a short period of global cooling. the past couple of centuries, human use of fossil fuels Most of the interactions between the geosphere and has radically accelerated the Earth’s natural carbon the Earth’s other subsystems; however, occur on the cycle, rapidly increasing the amount of carbon in the Earth’s crust, a relatively thin layer of rock at the surface atmosphere above natural levels.2 of the Earth. Living organisms, which are part of the biosphere, influence the composition of the soil, which Forcings is part of the geosphere. Mountain ranges cause clouds The Earth’s climate system—that is, the different parts to form, and rainfall, which is part of the hydrosphere, that combine to shape the climate around the globe— discussed below. involves interactions between various parts of the four subsystems just described. The Earth’s climate Hydrosphere system is also an open system. This means that it is not The hydrosphere refers to all the water on the Earth, in entirely self-contained. Solar energy radiated from the the ground, and in the atmosphere. It includes oceans, Sun is the Earth’s vital source of external energy. That freshwater rivers, and lakes as well as clouds and energy and the Earth’s climate system mix to shape water vapor. The hydrosphere also includes ice, which climatic conditions. Despite the change in weather some scholars count as its own subsystem called the from day to day, over longer periods our climate is cryosphere. Some of the most well-publicized details relatively stable. Climate, however, does change slowly of current climate change focus on the hydrosphere, over time. Scientists call the specific causes of climate including the melting of the ice sheets and sea ice- part change forcings. There are three particularly influential of the cryosphere at the planet’s North and South Poles, forcings that we will describe below: solar energy, the warming of oceans and rising sea levels, as well as volcanoes, and greenhouse gases. Texas Pentathlon - TX, TX increasingly severe droughts and flooding around the world. Solar Energy Energy from the Sun heats up the Earth. Everyone Atmosphere understands this reality from their own experience The atmosphere consists of various gases. Scholars of feeling the Sun’s warmth on a clear day. But what have defined atmospheric zones, or layers of these we cannot intuitively understand is that the amount gases. They are, from lowest to highest altitude: the of energy transferred from the Sun to the Earth is troposphere, stratosphere, mesosphere, thermosphere, not completely consistent over time and space. For and exosphere. One important way the atmosphere example, climatologists have identified that cooler affects climate change is through the greenhouse temperatures in the Northern Hemisphere in the late effect. Light that comes from the Sun is either 1600s and early 1700s corresponded to a period of absorbed by the Earth’s surface or reflected as heat. fewer sunspots and low solar activity.3 The movement The greenhouse effect occurs when gases in the Earth’s of the Earth and its relation to the Sun has been a atmosphere trap this heat inside the atmosphere, driver of climate change for hundreds of thousands of instead of letting the heat escape back into space. One years. The Milankovitch cycles reflect the fact that at greenhouse gas you may know is carbon dioxide, or intervals of around 100,000 years, 41,000 years, and CO2. Some amount of the greenhouse effect is good 26,000 years, the Earth completes different cycles that because it keeps our planet at a liveable temperature. influence which parts of the Earth receive more, or When there are too many greenhouse gases in the less, solar energy. These three cycles have interacted atmosphere, however, temperatures on Earth may with each other to steer the climate of the Earth into become too hot. and out of periodic ice ages.4 Biosphere Volcanoes The biosphere is all living things on, in, and around If you were outside on a hot day, you might seek the Earth. Life on Earth influences the chemical and shelter from the sun by moving to a shady area. The thermal makeup of the Earth’s subsystems. You may ground that has not been hit by the sun will be cooler already know about the carbon cycle, where humans than somewhere nearby that has been absorbing solar play a part by inhaling oxygen produced by trees and energy throughout the day. When large volcanoes 2024–2025 Social Science Pentathlon Resource Guide 7  Texas Pentathlon - TX, TX Volcanic gases in the atmosphere. Source: United States Geological Survey, Volcanoes Can Affect Climate | U.S. Geological Survey (usgs.gov). erupt, they emit a layer of dust and particles that can dashboard and other surfaces within the car, creating offer shade cover to large areas of the globe, creating a warming effect inside the entire car. Water vapor, cooler conditions over vast regions. When multiple carbon dioxide, and methane are some of the gases large volcanoes erupt one after another, the cooling that produce a greenhouse effect around the surface of impact can be great enough to influence large regions the Earth. Humans also release greenhouse gases into of the world and even bring down the average global the atmosphere in a variety of ways, contributing to temperature. increasing concentrations of greenhouse gases in the atmosphere and a more severe greenhouse effect. Greenhouse Gases The term “greenhouse gases” refers to the design of Positive and Negative Feedbacks buildings called greenhouses that capture heat from Because there are so many interconnected parts to the the Sun and are commonly used for agriculture. Earth’s climate system, when forcings begin to change Many people have probably experienced how this the climate, the four subsystems are impacted in many feels more frequently in automobiles that are very different ways. Reactions to climate change caused by hot on the inside after being parked in the sun with forcings are called feedbacks. Some feedbacks have the windows up. This occurs when solar radiation already been mentioned. One is the melting of sheets enters through the glass windows and warms up the of ice around the North Pole. Forcings that have caused interior surfaces of the car, such as the dashboard. climatic warming in the Northern Hemisphere have The windows also trap the heat that radiates off the resulted in this melting ice. 2024–2025 Social Science Pentathlon Resource Guide 8  Texas Pentathlon - TX, TX The greenhouse effect. Source: University of Calgary, Greenhouse effect - Energy Education. Scientists classify feedbacks as either positive or in the region alter features of the Earth’s subsystems. negative. In this context, “positive” and “negative” do Warmer temperatures affect the cryosphere, the ice not mean “good” and “bad.” The designation of positive portion of the hydrosphere, by melting ice that is on or negative refers to the relationship between the the surface of the ocean. This development alone original forcing and the impact of the feedback. If the has harmful consequences within the biosphere by original forcing and the feedback both push the climate destroying the habitat of animals such as the polar bear. in the same direction, either both warmer or both colder, But the melting ice is classified as a positive feedback then the feedback is positive. So, melting polar ice sheets because the loss of ice actually warms the climate, in is a positive feedback because warming caused the ice addition to the initial warming. When ice covers the to melt, and losing the ice further warms the climate. surface of the ocean, it reflects solar energy back away Positive feedbacks, therefore, keep pushing climate from the surface of the Earth. Water in the ocean that is change in the direction it is headed, either warmer or exposed after the ice melts absorbs more energy from colder. Positive feedbacks can push climate change the Sun, and the warming of the ocean is increased. to what is called a tipping point, at which time the change reaches a point of no return. Negative feedbacks, Examples of Negative Feedbacks conversely, serve to moderate climate change.5 Sometimes negative feedbacks also happen. If the initial change in climate is moving toward warmer Examples of Positive Feedbacks conditions, a negative feedback would be a reaction Melting ice sheets around the North Pole offer a clear to warming that causes colder conditions. A smaller example of a positive feedback. Warmer temperatures scale negative feedback occasionally occurs during 2024–2025 Social Science Pentathlon Resource Guide 9  SOURCES FOR RECONSTRUCTING THE HISTORY OF CLIMATE Even if a scientist or a scholar is equipped with an understanding of how climate operates and how climate change can occur, more information is needed 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— typically a physical collection 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.” Lake-effect snow over the Great Lakes. But climate scholars also search nature itself for clues Source: University of Michigan, Lake-effect Snow in the Great Lakes Region about climate’s history. Scholars call these figurative | GLISA (umich.edu) storehouses of sources the “archives of nature.”6 Sections II and III of this guide will cover the history Texas Pentathlon - TX, TX the winter season in the Great Lakes region in North America. Warmer conditions raise the water of human interactions with climate over roughly the temperature of the Great Lakes, increasing water past 10,000 years. Let’s discuss how scholars have in the atmosphere. The increased water in the air figured out what happened to our climate. over the Great Lakes, in turn, becomes cloud cover that cools the surface of the Earth by blocking the The Archives of Nature As discussed earlier, climate influences the four sunlight. Additionally, the clouds formed over the lakes subsystems—earth, water, air, and living organisms— sometimes bring lake effect snowstorms, creating a in many 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, The weakening of the polar vortex is another possible and so forth. Traces of those impacts are sometimes example of a negative feedback because it has recently found in the natural world. In fact, nature is an archive, caused unusually cold conditions in North America. or a repository, of clues about how climate and the Scientists hypothesize that warmer temperatures in the different parts of our world interacted in the past. oceans and atmosphere of the Northern Hemisphere Scientists and scholars have creatively developed have weakened the polar vortex of cold air that methods for observing and measuring evidence of past circulates around the North Pole. As warmer air moves climatic conditions that have been preserved in different upward, the cold air in the polar vortex moves out of parts of the world. its usual course and travels farther south into areas of Something observable in nature that gives an indication the United States that it had not previously reached. of past climate conditions is called a proxy. Proxies are In those places, winter temperatures drop well below natural features that show evidence of being impacted regular levels. In this case, the initial warming causes by specific climate conditions. If scholars can isolate colder conditions in some areas. Since the initial and date these proxies, they will have an idea of what warming and subsequent cooling do not align, it is a the climate was like at a certain time in the past. Three negative feedback. of the most revealing sources of climate history are ice, trees, and soil.7 2024–2025 Social Science Pentathlon Resource Guide 10  that year of the tree’s life. The tree can reveal if the year was dry or rainy and can even show the weather conditions of individual seasons in a year. The practice of gathering this information from trees is called dendrochronology—a combination of words that refer to trees and time. 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 Ice core sample. of the coral. Scientists creatively harvest data about Source: National Science Foundation, About Ice Cores | NSF Ice Core Facility the impact of past climate conditions on various parts of the Earth System and its subsystems. Through such Ice Cores discoveries, scholars learn about the climate of the past. Ice core sampling is a technique of drilling long cylinders of ice out of deep glaciers. The ice cores are The Archives of Society then analyzed in layers. As the ice was formed, the There is also evidence of past climate conditions in the archives of society. The term archives of society Texas Pentathlon - TX, TX snowfall from each year that became the new top layer of the glacier would trap particles from the atmosphere refers to documents produced by humans that contain and freeze them in the ice. Therefore, an ice core information about the climate. There are some from an old glacier can reveal what the atmospheric obvious limitations to the information scholars can conditions were dating as far back as hundreds of gain from the archives of society. Human records thousands of years.8 only describe conditions over the past hundreds or thousands of years, not the past millions of years Trees that some sources from the archives of nature reveal. Trees can also be analyzed for information about The oldest instrumental records date back only to past climatic conditions. One can identify the age of the thermometer’s invention around 1700. Newer a tree by counting the rings of a tree that has been documents are recordings of temperature. cut through. Scientists know how to analyze each of However, even before humans had modern scientific those rings for information about the weather during instruments, they left records that describe the climate. 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 Pentathlon Resource Guide 11  Texas Pentathlon - TX, 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. trends in the climate. Today, meteorologists measure whipplemuseum.cam.ac.uk/objects/11165/ daily records of high and low temperatures from many places around the globe. These records are very To make use of these records, scholars utilize a system precise, but they only go back a relatively short period of proxies similar to those used to study the archive of of time. For example, Phoenix, Arizona, received nature. While proxies produce less precise information attention in the news for record-breaking heat in the than a reading from a scientific instrument, they summer of 2023. But temperature records for the can still provide reliable information. For instance, city of Phoenix only date back to the year 1896.9 So, a narrative account of a flood in the 1500s will not instrumental records can clearly show trends in the contain an exact measurement of how much rain fell, climate, but only for a little more than a century. but scholars can reliably know that substantial rainfall did occur. One area in which the archives of society Today, scholars are constantly thinking about where are more specific than the archives of nature is in and how measurements should be taken to get the dating occurrences in nature. From tree records we clearest possible picture of what the climate is doing. may know that there was a good year of rain for plant For instance, scientists record the temperature at growth, but human records can give details down to different layers of the atmosphere to gain a more 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 2024–2025 Social Science Pentathlon 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 individual places at specific moments in time into an There are a variety of other types of records that accurate understanding of climate trends over larger people have left behind that also contain clues about areas and longer timespans. past weather and climate. Sometimes people made a marker of a highwater mark during a flood that Narrative Records one can see on a building. Works of art also show Even before people had the instruments to carefully depictions of weather conditions. Scholars need to record temperature and precipitation, they still paid be careful, however, to consider if the proxy they are Texas Pentathlon - TX, TX attention to the weather and other climate-related using accurately reflects real conditions. A painting is developments. Scholars can examine human-produced not the same as a photograph with a date. The artist records for clues about past climate conditions. may be depicting a real scene, or the inspiration for the These types of sources include weather diaries in painting may have come from elsewhere. which someone might have left short daily entries that document if it was hot, cold, rainy, cloudy, Grain prices are another proxy that scholars have used sunny, and so on. Ship logbooks often include such in the past as a marker for weather conditions. There information. Other narrative records might describe is a correlation between certain types of weather and whether a glacier is growing or receding, how high fruitful harvests that would cause prices to decline. the water level is in a river or lake, whether a lake is Recently, however, some scholars have argued that too frozen or not, or detailed descriptions of exceptional many other factors, unrelated to weather, might also occurrences, such as a long drought or a severe storm. drive grain prices up or down, and that prices do not accurately reflect weather conditions. Debating how to Scholars treat the information contained in narrative use sources is a healthy part of scientific inquiry and records as proxies for estimating the information leads to more refined and reliable methods for studying that modern scientific instruments can record such past climate conditions. as temperature, rainfall, or snowfall. If the narrative records contain an account of a cold winter and FIELDS FOR STUDYING THE describe a frozen river, for example, scholars can HISTORY OF CLIMATE devise systems for taking those records and comparing Because there are many different types of sources them with other records to gain an idea of climate that contain information about the history of climate, trends and conditions over time. To return to the different scholars have focused on becoming experts glacier example, accounts of glacier expansion are not at analyzing specific types of sources. Professionally the same as temperature readings that show an average trained scientists, social scientists, and historians are temperature decline, but the growth of the glacier all highly specialized. That means a scholar will likely works as a proxy to suggest that it is growing because only have expertise in researching climate history in a temperatures are declining. particular way. Sometimes, when a scholar identifies 2024–2025 Social Science Pentathlon Resource Guide 13 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 ways of 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 strong fields including many scholars and lots of research provides multiple 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. As previously discussed, every scholarly field also has its own strengths and limitations. The existence of multiple fields that examine climate Christian Pfister led the creation of the field of climate history. history offers us an opportunity to learn from the strengths of different fields and move beyond the limits reconstruct past climate conditions, and communicating of each individual field. Overall, the fields of historical Texas Pentathlon - TX, TX findings from nature according to the standard written climatology, paleoclimatology, climate history, conventions of the field of climatology. and the history of climate and society (HCS) offer complementary views of climate history. Together, Climate History they present a reliable picture of our climate in the past The field of climate history uses a different set and its relationship to human life. of practices to analyze different sources. Climate historians collect and study sources from the archives Historical Climatology and of society, and they analyze those sources according Paleoclimatology to historians’ methods and conventions. The skills Historical climatology and paleoclimatology are that climate historians bring to the study of climate different names for essentially the same field. include: the ability to read the language and script of Climatology is a study of climate that relies primarily the texts being analyzed; the ability to find the texts, on the archives of nature. Climatologists are experts analytical techniques, and the contextual knowledge at gathering information about climate from the to interpret the texts accurately; and the ability to investigation of the natural world, including the sources formulate and communicate historical narratives based described earlier, such as layers of ice, lake sediment on the textual evidence. The Swiss historian Christian or tree rings. The term “paleo-” means ancient or old Pfister (b. 1944) was an influential pioneer in the field and conveys a similar idea as the term “historical” in of climate history who diligently compiled sources and this context. Historical climatology or paleoclimatology developed methodical approaches to analyze them. He investigates climates of the past, particularly before the compellingly demonstrated that sources in the archives 1800s when scholars first utilized existing scientific of society can be used to produce trustworthy climate instruments for the purpose of creating widespread and reconstructions. systematic records of climatic conditions. A climate historian, therefore, looks in different places Historical climatologists must learn and practice than the historical climatologist for information about many skills, including, but not limited to: collecting past climate conditions. A scholar in one field would samples from nature (such as ice cores or tree samples), likely not have the training and expertise to accurately operating the machinery or instruments used to analyze analyze the types of sources that someone in the other the samples, analyzing the data obtained from nature to 2024–2025 Social Science Pentathlon 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 field does. The fields complement each other, however, a continent, or the entire globe. Different levels of because they take a look at the same topic from chronological scale could be days, decades, millennia, different perspectives. or millions of years. The History of Climate and Society HCS emphasizes the importance of precision when it Texas Pentathlon - TX, TX comes to scale. If a scholar only has sources from one (HCS) town, that evidence may not support a claim about an The History of Climate and Society (HCS) is a new entire region. Likewise, if the sources are all from a field that is just beginning to emerge. Environmental few decades, that data may not support a claim about historian Dagomar Degroot has led the push to entire centuries. Geographical scale and chronological form and name the field of HCS. The need for the scale are very important for the study of climate field, according to scholars within it, has stemmed history and its relationship to human life. from the recent expansion of studies on climate from a variety of fields including climate history CONCEPTUALIZING CLIMATE CHANGE and paleoclimatology, as well as other fields such as archeology, economics, geography, linguistics, TODAY and genetics. As its name suggests, the field of HCS Historians always study the past from the context of focuses on the relationship between past climate their own time. Historians try to be self-aware and conditions and human societies. consider potential biases from the present that might taint their understanding of the past. The relationship HCS scholars say that when it comes to studying how between present climate change and past climate climate and society affect each other, research from change, however, offers a particularly tricky challenge different fields is often not that precise. Specifically, for scholars. On the one hand, there is a lot of continuity HCS scrutinizes scholarly claims about climate’s between the past and the present in terms of how the past impacts on human society. HCS seeks to apply Earth’s subsystems interact to create climate conditions. rigorous analytical methods from the field of history Studying past climate change can help scientists and to make sure that sufficient evidence exists to support scholars understand what causes change and how the claims about climate causing certain social conditions. Earth reacts to forcings that cause climate change. To put it 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 area of the atmosphere—is unprecedented in human and one’s investigation. For instance, different levels of global history. Starting about two hundred years ago geographical scale could be a city, a large region, and increasingly since then, people have extracted and 2024–2025 Social Science Pentathlon Resource Guide 15  Texas Pentathlon - TX, 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. released fossil fuels at unprecedented levels. So, there era we live in today suggests that the climate change are also strong gaps between climate change today and we are experiencing at present is so significant that it climate change in the distant, and not-so distant, past. is comparable to epochs of very substantial climate change in the past. What word should scholars use to describe the relationship between today’s climate change and climate Concerns about Using the Term change in a broader chronological context? One answer “Anthropocene” to this question has come in the form of a term used to Adopting the term Anthropocene is a big decision, describe climate change today: the Anthropocene.12 The and some scholars have reservations about doing so. In term Anthropocene puts a strong emphasis on the cause science, systems of classification are very consequential of our current climate changes- “Anthro” means human. as these systems organize human knowledge. While referencing the broader context of geological Accordingly, scholars and scientists take them very history- the “cene,” designates periods of geological seriously. Do scientists really know enough about time that occur within the Cenozoic era. climate change today to decide that it is on the same The scientific divisions of geological time that level as the transitions into and out of the Pleistocene correspond to climatic conditions of the Earth and into the Holocene? That question is currently being over millions of years through to the present. The debated by scientists in the geological community. In current era, or epoch, is the Holocene, which began 2019, the Anthropocene Working Group (AWG), a body around 11.7 thousand years ago, at the end of the last of experts on the Earth’s geological epochs, proposed global ice age. The epoch prior to the Holocene, the that the Anthropocene should officially be recognized Pleistocene, started around 2.58 million years ago. as a new geological time period. They advocated that The use of the term “Anthropocene” to refer to the starting in the mid twentieth century, around 1950, 2024–2025 Social Science Pentathlon Resource Guide 16 the Holocene ended, and the Anthropocene began. In things have converged—or crashed together at once. March of 2024, the International Union of Geological Historians and scientists are still sorting out the Sciences rejected a proposal to formally name the combined story of climate history and human history. Anthropocene as a new geological epoch, but noted that the term will “continue to be used not only by Earth and Just as scholars in scientific fields constantly revise environmental scientists but also by social scientists, their conclusions when new information becomes politicians and economists as well as by the public at available, historians also update the stories they tell. large” and “will remain an invaluable descriptor of They make their narratives more precise and accurate human impact on the Earth system.”13 According to the with new findings. This process has been very evident formal geological time scale accepted by the geological as scholars have tried a variety of approaches to community, we still live in the Holocene.14 integrating climate history and human history. The changing process in which historians are trying to Arguments for Using the Term understand the role that climate has played in past civilizations and how that history relates to the present “Anthropocene” is both fascinating and important. Should we use the term Anthropocene even if scholars in the geological community who could make the term Mapping Climate onto Existing official have not done so? Putting the Anthropocene in the official geological time scale is a very high Narratives bar to reach. The fact that geologists are so cautious One obvious approach to bringing together existing about naming a new geologic era reflects the level of historical narratives and new information about seriousness they bring to their work. climate history is to simply place the two histories over one another. Historians have well established Texas Pentathlon - TX, TX An important reason to use the term Anthropocene is narratives about most parts of the world. Often, these that other scholars and the public use this term already. narratives divide history into a series of stages that The evidence overwhelmingly suggests that 1950 is are marked by political developments. The history an appropriate marker for the start of current warming of China over the past several thousand years, for trends in the climate. Scholars are debating whether instance, can be portrayed neatly as a timeline of the mid-twentieth century qualifies as an epochal successive dynasties: Xia, Shang, Zhou, Qin, Han, and change comparable to the Holocene. Meanwhile, so forth. For the Mediterranean World, the common something drastic is taking place in today’s climate. story goes from the Greek Empire to the Roman The term Anthropocene has become a way to name Empire to the Middle Ages and so on. what is happening, making it easier for scholars, journalists, and members of the public to have vitally One option for combining climate history with important conversations about our changing climate.15 existing historical narratives is to look at key historical moments, like transitions from one dynasty to another. CLIMATE CHANGE AND Then, researchers explore any climatic events—such as a period of climate change—that coincided with these NARRATIVES OF GLOBAL HISTORY significant events. Scholars who employ this technique Humans have been telling narratives, or stories, about are able to show striking correlations between large- global history for millions of years. Professional scale social events, such as mass revolts in a region, historians have been telling stories about global and climate-related conditions, like an extended period history since the modern historical profession became of drought. The climate events and the social events formalized in Europe in the 1800s. But with a few often line up to such a degree that it seems to be more exceptions, such as the French historians E. Le Roy than a mere coincidence. Ladurie and Fernand Braudel, modern historians, did not include climate in their narratives of global A potential weakness of this approach, however, is history until around the year 2000. Climate was not that it is not the best practice in history or science for included in traditional histories of the world until scholars to desire to prove too specific of a thesis before the past two and a half decades. Since historians they begin to study their sources. This is because began incorporating climate into world history, many such an approach could lead to biases in the results. 2024–2025 Social Science Pentathlon Resource Guide 17  Texas Pentathlon - TX, 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. 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 be too limiting. This may reduce climate history to conditions cause revolts and revolutions? Older just retelling stories based on the old frameworks of the scholarship—including some of the pioneering works rise and fall of dynasties and empires. of history that first gave attention to climate history as a factor in human history—made the case that Climate Determinism and the Question climate determined or dictated the course of human of Causal Relationships history. More recent studies have cast doubt on such Attempts to combine climate history and human a strong link between climate and the development history have also raised challenging interpretive issues. of human culture and society. Recently, the argument In other words, it is hard to determine if one event in that climate sets the course for human history has been history caused a second event, or if they just happened labeled climate determinism. Almost all studies of coincidentally. Often, there is not enough evidence to climate and society today say that they are rejecting definitively prove the cause-and-effect relationship. climate determinism, but some scholars still argue that Historians need to use careful reasoning to offer an climate played a major role in shaping human history. interpretation of the available evidence that suggests Scholars may be able to show a correlation between a why and how something might have caused something certain climatic condition and a human event, but that else.16 does not actually prove that the first one caused the In the context of the history of climate and society, a second one. In the field of the history of climate and society, scholars place emphasis on the careful study 2024–2025 Social Science Pentathlon Resource Guide 18 and analysis of causal mechanisms. This approach asks: “What specifically did the climate impact? In what way did that impact trigger a human response?” The 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 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 evidence to create historical accounts of what human life was like as far back as around 40,000 years ago. Most often, historical studies focus on human events Texas Pentathlon - TX, TX in the much more recent past, such as the twentieth century. However, a few thousand years of human history amount to little more than a blink of an eye when compared to the millions of years over which the Earth’s climate has evolved to become what it is today. In what meaningful way can scholars compare these two vastly different chronological scales? Rachel Carson in 1960. Source: https://www.rachelcarson.org/ In the past, scholarly fields that study the science of climate change and scholarly fields that study human histories did not overlap. The current state of climate the Earth. Her book compellingly demonstrated how change caused by human behavior—known as the commercial pesticides destroyed living organisms Anthropocene—has brought these two histories and radically transformed ecosystems in mere years, together at the moment in time in which we currently whereas natural changes in an ecosystem could only live. Scholars are in the process of figuring out how evolve over the course of decades or generations. 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 Incongruent Chronological Scales climate systems in a timespan that is exponentially Because humans before the twentieth century did shorter than natural processes.18 Today’s climate not have the capability to impact climate on the scale change, therefore, is an event that takes place on the that humans do today, humans arguably lacked an small scale of human history because humans are a awareness that their actions even had the potential to leading cause of climate change. But the changes are shape the world in such a forceful and lasting way. also so substantial that they have become part of the Although she was not writing about climate, Rachel story of the Earth’s climate that has developed over Carson (1907−64), with her 1962 book Silent Spring, a much greater scale (millions of years). Thus, while is often credited with helping humans develop an these two chronological scales are not the same, they awareness of how much potential we now have to alter nevertheless have now intersected in our lifetime. 2024–2025 Social Science Pentathlon Resource Guide 19 The Novelty of the Anthropocene (positive feedbacks), while other times The novelty, or newness, of the Anthropocene presents reactions in nature act against the initial the social science scholar and the social science student drivers of climate change (negative feedbacks). with unprecedented challenges. Old methods and old 6 Scholars and scientists learn about climate narratives in the field of history must now account for history by investigating evidence in the natural new discoveries from fields that examine climatology. world (archives of nature) and in records left by Scholars and the public wonder if anything from humans (archives of society). history relates to the Anthropocene and if there are 6 Historical climatologists and paleoclimatologists any lessons from the past that can guide us through study the archives of nature. Climate historians the challenges of the multiple natural crises that study the archives of society. Scholars in the humanity now faces. These are real challenges, but field of the history of climate and society (HCS) they also offer exciting new opportunities. The project focus on the relationship between climate of uncovering and sharing the combined history of history and human history. climate and humanity is already allowing us to see ourselves and our world in new ways. 6 The Anthropocene is a term that scholars and the public have begun using to describe SECTION I SUMMARY the idea that current climate change might 6 The field of Earth System Science (ESS) mark the beginning of a new climatic and provides key concepts for understanding the geological epoch in the Earth’s history. The nature of the Earth’s climate and climate term Anthropocene also reflects the reality that change. current climate change is significantly caused by human actions. The Earth’s four subsystems—earth, water, air, Texas Pentathlon - TX, TX 6 and living organisms—interact on local and 6 It is a challenge to combine climate history global levels to shape climatic conditions. and human history into a single story, but by attempting to do so, historians help us better 6 Forcings—events such as volcanic eruptions, understand our changing climate. variations in solar energy reaching the Earth, and rising concentrations of greenhouse gases in the atmosphere—can tip the balance between subsystems and cause climate change. 6 Sometimes, climate change causes reactions in nature that drive the change even more 2024–2025 Social Science Pentathlon Resource Guide 20  Section II Humans in the Holocene SECTION II INTRODUCTION and other activities that impact the environment can be According to the International Union of Geological found nearly everywhere on the planet.23 Sciences (IUGS), the geological and climatic epoch Climate and environment do not determine the course known as the Holocene began about 11,700 years ago.19 of human development and history. That said, there are During the Holocene, humans have thrived like never many, climatic conditions in which humans could not before. Whether one dates the origins of humanity to survive, let alone thrive. The specific course of human the oldest fossil record of Homo sapiens around 300,000 history over the past 12,000 years is not the inevitable years ago or to around 40,000 years ago when Homo outcome of human life in the Holocene. Climate did not sapiens became the last surviving members of the Homo determine the twists and turns of the human story, nor genus, humans had a much longer history on Earth did it dictate that humanity would be standing where we before the start of the Holocene than we have had since are today. Yet, it is undeniable that the Holocene is the it began.20 However, our species never came close to Texas Pentathlon - TX, TX historical setting in which humans grew to become the building what humans have built during the Holocene. global force we are now. Humans have not flourished Before the Holocene, the global human population completely in a vacuum. We have thrived under very may not have surpassed ten million.21 According to the specific environmental conditions—the conditions of United Nations, the current global human population the Holocene. At a minimum, one must know what is over eight billion.22 Traces of human manufacturing the Holocene is to be aware of the stage on which the 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) 2024–2025 Social Science Pentathlon Resource Guide 21  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. human drama has played out. The general marker of the start of the Holocene, roughly 11,700 years ago, is the end of the last ice age. The world that humans lived in prior to the Holocene was very different than the environment we have known since. Most of the history of Homo sapiens took place in the Pleistocene Epoch (2.6 million years ago to 11,700 years ago), a period characterized by cycles of glaciers growing or receding and, at times, covering vast portions of the Earth’s surface. The Last Glacial Texas Pentathlon - TX, TX Maximum (LGM) occurred around 20,000 years ago. At that time, much of what is known today as Europe, including Scandinavia, the British Isles, and parts of central Europe, were covered by ice. Much of North America was as well. Asia experienced permafrost— perennially frozen ground.24 So much of the world’s water was frozen on the Earth’s surface that ocean levels were hundreds of feet lower than current levels. Since the LGM, the ice has receded and melted into the ocean, but it has not melted at an even rate over time. Warming caused by solar cycles contributed to a major glacial meltwater event that started around 14,000 years ago and, in turn, cooled ocean temperatures and reversed warming trends for roughly a millennium. That cold millennium is known Location of NGRIP2 ice core sample, indicated in bold font. as the Younger Dryas period (c. 12,900 to 11,700 years Mike Walker, Martin J. Head, John Lowe, Max Berkelhammer, Svante Björck, et al, “Subdividing the Holocene Series/Epoch: formalization of ago). Since its conclusion, the world resumed warming stages/ages and subseries/subepochs, and designation of GSSPs and auxiliary in a new epoch known as the Holocene. stratotypes,” Journal of Quaternary Science 34 (2019): 176. AN OVERVIEW OF THE HOLOCENE period dates from 8,236 to 4,250 years ago and is Scholars divide the Holocene into three periods. The known as the Middle Holocene Subseries/Subepoch three periods are dated according to how many years go or the Northgrippian Stage/Age. The third, and final, they started and ended, with the year 2000 CE marking period runs from 4,250 years ago to the present and is the present. The first period lasted from 11,700 to 8,236 known as the Late Holocene Subseries/Subepoch or years ago and is named the Early Holocene Subseries/ the Meghalayan Stage/Age. Each of these three periods Subepoch or the Greenlandian Stage/Age. The second are described in more detail below.27 2024–2025 Social Science Pentathlon Resource Guide 22  Texas Pentathlon - TX, 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. The End of the Last Ice Age and the all over the globe. So, to understand how the change from the Pleistocene to the Holocene affected people, Early Holocene we need to look at specific areas because every place The Early Holocene lasted from around 11,700 to 8,236 in the world is different. New research has investigated years ago. It occurred during part of the warmest period how humans lived during the Early Holocene on the of the Holocene—the Holocene thermal maximum-from Iberian Peninsula at the western edge of Europe and around 11,000 to 7,000 years ago. The classification in Madagascar off the east coast of Africa.29 In North of the Early Holocene as the Greenlandian Stage/Age America, the beginning of the Holocene appears to refers to the ice core taken in Greenland, NGRIP2, happen at the same time as the extinction of dozens which bears evidence of the start of the Holocene at a of large mammals. One popular explanation for the depth of 1,492.45 meters into the ice. The end date of disappearance of these mammals is that humans the Early Holocene coincides with a meltwater event in hunted them to extinction. Other scholars point to Canada, when a glacial ice sheet collapsed. a lack of evidence for that hypothesis and suggest By the start of the Holocene, humans had already that the decline of the animals was the result of their migrated out of Africa across Eurasia to the east and inability to adapt to a changing climate.30 west, to Australia, and to the Americas from the north These few examples highlight that climate change was to the south.28 In other words, humans were already 2024–2025 Social Science Pentathlon Resource Guide 23  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. factors. Known as the Mid-Holocene Transition, this Dyke, A.S. (2009). Laurentide Ice Sheet. In: Gornitz, V. (eds) Encyclopedia of Paleoclimatology and Ancient Environments. Encyclopedia of Earth period marks a turn toward the cooler temperatures that Sciences Series. Springer, Dordrecht. would continue in the Late Holocene.32 not the same everywhere on the globe, and that even During the years of the Middle Holocene, humans in a specific location, the interactions between climate, lived—as before—in diverse environmental and social conditions around the globe. In Eurasia, people Texas Pentathlon - TX, TX nature, and humans were tricky. Local environmental conditions and factors that are unique to individual developed important practices that are seen as key human communities make it necessary for scholars steps for humans. In the later centuries of the Middle and scientists to closely study specific geographical Holocene, which historians consider as the transition regions. Broad statements aren’t always accurate. In from the Stone Age to the Bronze Age, humans began general, humans still largely hunted and maintained utilizing metal instruments in new ways. agricultural mobile communities during the Early Holocene period. societies also emerged, including, most notably, the Agricultural practices— including such as growing Mesopotamian civilization around 5,500 years ago, corn or wheat in the Americas— increased, but the or 3500 bce. Scholars continue to investigate the role large agricultural societies typically counted as the of climate in the development of Eurasian settlements first of their kind in human history did not emerge during the Middle Holofne, but it seems clear that local until the Middle Holocene period.31 social dynamics, along with climatic factors, influenced the fates of burgeoning human communities.33 The Middle Holocene The Middle Holocene, also known as the Northgrippian The Late Holocene Stage/Age, began around 8,236 years ago and ended The Late Holocene, or Meghalayan Stage/Age, began 4,250 years ago. Its name also refers to an ice core from around 4,250 years ago and continues to the present. the same location in Greenland showing evidence of The name “Meghalayan” refers to the location of cooler temperatures, similar to the Early Holocene. a cave in northeast India where mineral deposits The beginning date of the Middle Holocene, 6200 bce, contain evidence of a climatic event that geologists coincides with the collapse of the glacial Laurentide use to mark the beginning of the Late Holocene. At Ice Sheet in Canada, which accelerated the flow of icy a time known as the Holocene Turnover, roughly water into the ocean in what is known as a “meltwater 4,250 years ago, abrupt changes in atmospheric and event.” Despite the cold water flowing into the ocean, oceanic conditions led to sudden alterations in weather temperatures in the Northern Hemisphere remained conditions around the world.34 The question of whether high for another thousand years. Around 7,300 years or not the Late Holocene has ended and given way ago, between 5300 and 3700 bce, temperatures began to the Anthropocene is a matter of debate. Some to decline due to weakened solar energy, among other scholars favor an official adoption of the Anthropocene 2024–2025 Social Science Pentathlon Resource Guide 24  and a starting date of 1950, which would then mark the end of the Late Holocene and the Holocene altogether.35 However, in 2024 the International Union of Geological Sciences rejected a proposal to name the Anthropocene as an official, new geological epoch. The Late Holocene starts roughly around 2250 bce, and spans a period of human history that is well documented. Moreover, historical narratives of various parts of the world date back to the start of the Late Holocene or earlier. The next part of Section II will discuss the challenge of evaluating these historical stories in relation to the climate history of the Late Holocene. CLIMATE AND THE DEVELOPMENT OF HUMAN CIVILIZATIONS A good way to start understanding the relationship between climate history and human history is to align the timelines of both histories. Yet, even this seemingly simple task has its challenges. One pitfall is that scholarly fields in climatology typically date past Texas Pentathlon - TX, TX events—as we have been doing so far in this section— according to how long ago they happened, using 1950 ce (Common Era), or 2000 ce as the present. So, the Holocene began 11,700 years ago, using the year 2000 ce as the marker for the present. In our narratives of human history, scholars use a calendar system that counts down to the year 0 and then counts up from there, bringing us to the year 2024. According to this system, the Holocene began in 9,700 bce (Before Common Era). centuries ago, scholars used the year of the alleged birth of Christ as the reference date for the “year zero.” This is why you may also have heard people use BC (Before Christ) or AD (Anno Domini, Latin for “In the year of the Lord”) instead of bce and ce. As confusing as it may seem, scholars and students studying climate history and human history together must keep two dating systems in mind and be ready to calculate quickly. For instance, the Late Holocene began 4,250 years ago which is the same as 2250 bce. Another pitfall when trying to synchronize climate history and human history is that it is hard to understand the different scales of the historical timelines. The Sediment sample from Mawmluh Cave, Meghalaya, northeast Pleistocene is only one of the most recent geological India, showing the position of the 4.2‐ka event. epochs, and it lasted a miniscule 2.6 million years Source: Mike Walker, et al, “Subdividing the Holocene Series/Epoch,” 178. out of the Earth’s four-billion-year history.36 Yet, from 2024–2025 Social Science Pentathlon Resource Guide 25  Texas Pentathlon - TX, TX The spread of agriculture in the Near East. Source: Teaching the Middle East, The University of Chicago Library the perspective of human life, 2.6 million years is a civilizations that began around 3500 bce. We will staggering amount of time that dwarfs the entire history explore up until the late Middle Ages in Europe, around of humanity. (Because climatologists deal with such 1350 ce. When talking about the Earth’s climate history, large numbers, it is conventional in their field to round this period stretches from the last centuries of the years to a number such as 2.6 million.) Middle Holocene into the Late Holocene. This happened just before the Little Ice Age (LIA). One may also notice that sometimes scholars in climatology use 1950 ce and sometimes they use 2000 Early Agrarian Societies ce as the date they count back from when dating an Traditionally, scholars have counted the development event that happened many thousands of years ago. of large agrarian, or agricultural societies, to be a While fifty years feels like a lifetime in our daily milestone in human history. Although humans had experience, it is largely within the margin of error when cultivated some crops throughout the Holocene, estimating the dates of past climatic events throughout starting around 3500 bce, new agriculturally based the Holocene. When we talk about the beginning of societies emerged. These societies were much larger civilization in places like Mesopotamia around 3500 than previous human settlements. The people living bce, it’s important for both students and scholars to there stayed in one place for a long time and made keep in mind that all of the recorded human history we big changes to their local environments, including the know about falls within a tiny sliver of climate history. building of impressive structures. They also developed Conversely, climate typically changes at such a slow rate forms of writing, initially for recordkeeping, that that some scholars argue that people throughout history were used for other purposes like storytelling. These were largely unaware of any climatic changes that might societies had a complicated social structure, where have occurred during the span of a single human life.37 people belonged to different groups or “classes.” In the past, scholars have made a value judgment that Next, we are going to look at an important part of the emergence of features such as these represents the human history, starting with the Mesopotamian dawn of human civilization. However, more recently, 2024–2025 Social Science Pentathlon Resource Guide 26  Texas Pentathlon - TX, TX Egyptian artifact from around 3100 bce. Source: Ashmolean Museum, University of Oxford Bronze head depicting an Akkadian ruler. systems. The Sumerians in Mesopotamia developed writing, had a class of priests, and planned cities some scholars have critiqued the practice of ranking between around 3600 and 3000 bce. Subsequent civilizations based on such markers.38 powers in the Mesopotamian region included the Akkadians, Babylonians, Assyrians, and Persians. Early agrarian, or farming, communities were closely linked with nature because of their work with plants A notable climate-related event occurred in and animals, so it might be easy to see how the Mesopotamia around 2250 bce. As previously weather and environment affected these people’s lives. mentioned, the year 2250 bce marks the boundary Based on this idea, if a society relies on farming, then between the Middle and Late Holocene. In any weather changes that affect crops would directly Mesopotamia and nearby regions, the abrupt climate link the climate to how people in that society live. changes of that moment may have resulted in cooler and In reality, the relationship between humans and the dryer conditions.40 The ruling empire in Mesopotamia broader natural world at the time was the Akkadian Empire, which had been established nearly two hundred years before, around Mesopotamia 2334 bce. However, the empire collapsed by around Mesopotamia, located in and around the current 2218 bce. Were climate change and drought the cause national boundaries of Iraq, was home to several of of its demise? Some scholars argue that they were. the most influential empires in Eurasian history. The These scholars point to simultaneous societal collapses region received more rainfall during the establishment in Egypt and other regions.41 Others, however, take a of its early societies than it does today. The region’s more geographically focused approach and have argued water supply came from the Tigris and Euphrates that even within Mesopotamia individual cities reacted Rivers and was enhanced by human-built irrigation differently to the changing climate, and that not all 2024–2025 Social Science Pentathlon Resource Guide 27  Remains of Mohenjo-Daro, a city in the Indus Valley built around 2500 bce. Source: Woods Hole Oceanographic Institution. Ancient Indus Valley Civilization & Climate Change’s Impact (whoi.edu) cities in the area even declined.42 This discussion shows how hard it is to match data from the archives of nature Olmec Figure from the ninth to twelfth century bce. and the archives of society. It also shows experts might Source: The Metropolitan Museum of Art. end up with different answers. The picture changes depending on if you look at empires as a big picture, or with lots of other villages and cities. Then, during the study individual cities. Late Harappan period from 1900 to 1000 bce, people Texas Pentathlon - TX, TX Egypt started leaving the big cities to live in smaller villages Not far from Mesopotamia, another powerful society instead. Experts aren’t sure why this once-great society arose on the Nile Delta in Egypt. By around 3200 bce, started to decline. Since there’s no evidence they were the Egyptians had started their own form of writing. attacked, some think changes in the weather might They built colossal monuments, including iconic have had something to do with it. Once again, some p