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xv The authors wrote in a friendly and approachable tone just for you! The text will engage you and spark an interest in (and maybe even a passion for) Human Geography. %u2026tone and level Module 7 Population Distribution and Its%u00a0Consequences 1012 Population Distribution and Its%u00a0Consequences 7 MODULE LEARNING GOALS 7-1 Describe how population is distributed around the world. 7-2 Identify the factors that influence population distribution. 7-3 Explain the three methods for calculating population density. 7-4 Explain the consequences of population distribution and density. When geographers study the human population, they are first and foremost interested in learning how humans are spread out on Earth%u2019s surface %u2014 that is, the pattern of population distribution . In this Module, we discuss the striking unevenness of this pattern at different geographic scales, the factors that have shaped it, and the three ways of measuring population density. We also examine the impact of population distribution on society, the economy, and the environment. Earth is home to more than 8 billion people. Where do all these people live? In major metropolitan areas around the world such as New York, Los Angeles, Mexico City, Istanbul, Shanghai, and Dhaka, millions or even tens of millions of people are crowded into relatively small areas. Yet much of Earth%u2019s surface is sparsely populated. This very uneven distribution of human population is one of Earth%u2019s most striking geographic features, and we see it at the global, regional, national, and local scales. Geographers seek to understand the unevenness in human population distribution, the reasons behind it, and its consequences Global Population Patterns 7-1 How is population distributed around the%u00a0world? The global distribution of human population is highly uneven. Roughly 7 billion of the world%u2019s population lives in the northern hemisphere. The southern hemisphere, which has vast expanses of oceans but a limited amount of land surface, is home to just over 1 billion people (less than the population of India or China). Furthermore, about two-thirds of the world%u2019s population is found in the areas with middle latitudes, between 30%u00b0 and 60%u00b0 north and south, roughly corresponding to the subtropical and temperate areas on Earth, especially in the northern hemisphere. Overall, a whopping three-quarters of humanity lives on only 5 percent of Earth%u2019s surface. Humans seem to universally prefer living in relatively flat, low-lying areas. About 80 percent of humans live in places that are less than 1640 feet (500 meters) above sea level. People worldwide also appear to enjoy ocean views or relatively easy access to a large body of water. More than half of the world%u2019s population is within 124 miles (200 km) of an ocean and two out of TERMS TO KNOW population distribution: The pattern in which humans are spread out on Earth%u2019s surface Module 4 Human-Environmental Interaction 59Preparing for the AP%u00ae Examfor recent global warming. The Intergovernmental Panel on Climate Change (IPCC), a group of scientists from many different countries, concluded that because of increased greenhouse gases, average global temperatures are likely to rise between 2.5%u00b0F and 10.4%u00b0F above 1990 levels by 2100. During their annual climate week summit in September 2023, the IPCC confirmed that without immediate action to reduce emissions and adapt to continued warming, threats to planetary health and human systems are inevitable. The question, then, is not whether the climate is warming, but what to do about it. The first step, scientists argue, is to find ways to decrease levels of carbon dioxide released by looking to new technologies and alternative energy sources. Yet, at the same time, we must deal with the effects of global warming that are already occurring. Geography is a discipline well suited to confronting global warming effects because, as we have seen, one of its primary activities is to understand nature%u2013culture relationships. Valued cultural landscapes, cities, and farmlands will all be affected, and human geographers will no doubt be on the front lines of mitigating those effects. Continuing the Debate As geographers, we know that various cultures interact with the environment differently and have varied beliefs and ideas about the role of science in explaining physical phenomena. Keeping all this in mind, consider these questions: %u2022 How might such cultural differences affect people%u2019s conclusions about the causes and effects of global climate change? %u2022 How are your ideas about global climate change affected by your position in the world? Why is Earth%u2019s climate warming? As our dependence on fossil fuel combustion has grown, atmospheric carbon dioxide and global temperatures have risen in tandem. georgeclerk/Getty Images TERMS TO KNOW renewable resources: Natural resources that Earth will naturally replenish over time Unlike nonrenewable resources, renewable resources are plentiful, and Earth will naturally replenish them over time. These resources include the sun (for solar AP %u00ae Exam Tip All use of natural resources involves humanenvironmental interactions with positive and negative impacts for various groups. To evaluate the environmental impact of any practice, you will need to analyze the practice at various scales and assess consequences for different groups. energy), wind (for wind energy), water (for hydroelectric power), and Earth%u2019s interior (for geothermal energy). Many countries, including Iceland, Sweden, Denmark, and Guatemala, promote policies and incentives for industry and private citizens to use more of these renewable resources for energy production. Environmental Impact Population distribution and density may also have environmental consequences. Heavily populated areas, especially large metropolitan areas such as Los Angeles, London, Mexico City, and Delhi, usually have poor air quality compared to rural areas ( Figure 7.12 ). The need to build more homes, roads, and shopping centers to accommodate a growing population often leads to loss of habitats for wildlife, farmland for food production, and green spaces that many people value. Geographers and other scholars have long debated Earth%u2019s carrying capacity , or the number of people it can support and sustain. Many factors, including climate, land productivity, technology, and consumption level, affect carrying capacity, so it is not easy to come up with a definitive answer. Many densely populated areas may not have reached their capacity, but some thinly settled regions may be severely overpopulated relative to their ability to support population, usually because of poor quality of agricultural lands. We revisit this issue in Module 11, where we discuss theories of population growth and food production. Political Impact In the United States, population distribution affects political power distribution. After the U.S. census is conducted every 10 years, the 435 seats in the U.S. House of Representatives are reapportioned among the 50 states based on population change so that each representative serves about the same number of people (currently 761,169 people on average based on the 2020 census). Because the Sunbelt states in the South and Southwest have been growing in population while several Northeast and Midwest Snow Belt states have stagnated or lost population, the former have gained seats at the expense of the latter, thus shifting some political power to the South and West. Between 2000and2010eightstatesArizonaFloridaGeorgia TERMS TO KNOW carrying capacity: The number of people a particular environment or Earth as a whole can support on a sustainable basis human well-being: The state of being comfortable, healthy, or happy Module 7 Population Distribution and Its%u00a0Consequences 115over a large area, which made the spread of the disease more difficult. In addition, the increasingly dense population distribution is contributing to the severity of losses from natural disasters such as floods and earthquakes because more people now live in hurricane- and earthquake-prone areas, such as the coastal areas of the United States. In this Module, we examined population distribution at different geographic scales, from global to local. We identified the four major population clusters and the sparsely populated areas on Earth. Unevenness is a key characteristic of population distribution regardless of the scale of analysis. This distribution pattern is shaped by a number of physical, social, and cultural factors. Population tends to be the most dense where the terrain is level, the climate is mild and humid, the soil is fertile, mineral resources are abundant, and the sea is accessible. Population tends to thin out with excessive elevation, aridity, coldness, ruggedness of terrain, and distance from the coast. The distribution and density of population have social, economic, political, and environmental implications. consider desirable. More and more people are living in cities worldwide because cities, particularly big cities, offer many amenities that people enjoy even though air quality may be worse, housing usually costs more, and traffic congestion is common. Fortunately, urban planning and technology may help to reduce or even eliminate some negative aspects of city life. For example, air quality in London has improved significantly over time while its population has grown. Disease and Natural Disasters Population distribution and density may affect people%u2019s health and vulnerability to natural disasters. Infectious diseases may spread faster in densely populated areas. For example, malaria is a major killer in tropical African countries such as Gambia. Malaria is caused by five types of parasite, which spread through mosquito bites. One contributing factor is that more and more people in African countries now live in crowded cities and towns so more people may get infected. In the past, many people lived in rural villages dispersed Module 7 Review 7-1 How is population distributed around the%u00a0world? %u2022 Population distribution is highly uneven at global, regional, national, and local scales. %u2022 There are four major population clusters in the world, but much of Earth%u2019s surface is sparsely populated. %u2022 Population size and land area by country vary greatly. The top 10 countries in terms of population will change because their populations are growing at different rates. 7-2 What factors influence population distribution? %u2022 A number of physical, cultural, and economic factors have shaped the population distribution patterns on Earth. %u2022 The key factors that affect population distribution patterns may depend on the scale of analysis. 7 -3 What are the three methods for calculating population density? %u2022 Arithmetic or crude population density refers to the average number of people per unit area of land. %u2022 Physiological density is the ratio of population to arable land (i.e., land suitable for agriculture). It is a good indicator of the pressure that the population exerts on the land resource and agriculture. %u2022 Agricultural density is the average number of farmers per unit area of arable land. It reflects the labor intensiveness of agriculture. 7-4 What are the consequences of population distribution and density? %u2022 Population distribution and density can affect economic development, political power distribution, the environment, and human health and vulnerability to natural disasters. Preparing for the AP%u00ae ExamLearning Goals Reinforced Throughout the ModuleLearning Goals are listed at the beginning of each Module to focus your reading and guide your comprehension. Bulleted summaries conclude each Module, highlighting key takeaways that you should master before moving on. Running Glossary In this vocabulary-heavy course, watch for the green Terms to Knowboxes, which define each boldfaced term on that same page. The key terms are repeated in the Terms to Know section at the end of each Unit and in the Glossary/Glosario at the end of the book. Exam Tips Whether you%u2019ve taken AP%u00ae exams before or this will be your first, you know that the best way to go into any exam is to be prepared. Our AP%u00ae Exam Tips , found in each Module, will help you to focus on important content and avoid potential pitfalls on exam day. %u00a9 Bedford, Freeman & Worth Publishers. For review purposes only. Do not distribute.