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Examine the photo of the wind turbines. How do you think they generate electricity?

Guiding Questions

• What are the world’s environmental challenges?
• How have advances in biotechnology, medicine, digital technology, and communication affected the world?

Vocabulary

• fossil fuel
• pollution
• Environmental Protection Agency
• climate change
• drought
• emission
• biotechnology
• AIDS
• Internet
• smart phone

Academic Vocabulary

• organic
• enhance

Responding to Environmental Challenges

As the global economy grew, it consumed larger amounts of energy. Most of that energy came from fossil fuels, such as oil, coal, and ­natural gas.

Fossil fuels are fuels formed in the distant past that have limited supplies. Once they are burned, they are gone and cannot be replaced. They also cause environmental damage by polluting the air when they are burned. Pollution, or harmful impurities added to the environment, is a worldwide problem. Air or water pollution from other countries may affect the United States.

Analyze Charts The use of fossil fuels has had a significant impact on the climate.

Synthesize Visual Information How much is the global temperature predicted to rise between 1900 and 2100 with continued heavy use of fossil fuels?

What Is the Environmental Movement?

The modern environmental movement began in the 1960s with the publication of Silent Spring. In this book, Rachel Carson, a marine biologist, warned readers of the dangers of DDT. DDT is a chemical that farmers used to kill insects. Carson explained that DDT sprayed on crops did not just kill insects. It killed birds and fish and even threatened human food supplies.

Congress responded by passing a law to restrict the use of DDT. Soon environmental groups like the Sierra Club, the National Wildlife Foundation, and the Audubon Society lobbied Congress for additional protective laws. In 1970, President Richard Nixon created the Environmental Protection Agency (EPA). In the same year, environmentalists held the first Earth Day.

In the 2000s, environmentalists throughout the world continued to address global problems. They were concerned about many issues. These included groundwater contamination, chemical spills, depletion of the ozone layer in Earth’s atmosphere, nuclear waste disposal, reliance on fossil fuels, the extinction of plants and animals, and the destruction of the rainforest.

The Issue of Climate Change

Climate change is any measurable long-term change in climate. Climate change may affect precipitation, wind patterns, or temperature. Global warming, defined as an increase in average temperatures near Earth’s surface, is one form of climate change.

According to the Environmental Protection Agency, during the 1900s, the temperature near Earth’s surface rose 1.4 degrees Fahrenheit. The EPA estimated that the temperature would increase another 2 to 11.5 degrees by 2100.

In the early 2000s, scientists expressed concern that climate change could affect farming, the water supply, personal health, and the weather. Scientific studies suggested that climate change had caused some areas, such as the eastern United States, to experience heavier rain and increased flooding.

Other areas, such as the western United States, had less precipitation and more frequent droughts. A drought is a shortage of water that affects plants and animals and energy production and increases the risk of wildfires.

Climate scientists concluded in the early 2000s that humans were the greatest contributors to climate change. Burning fossil fuels released carbon dioxide and other greenhouse gases into the atmosphere. Greenhouse gases, which blanket Earth, are gases that trap energy and cause the temperature to increase.

Some amount of greenhouse gases is needed for a stable climate, but too much will permanently change Earth’s climate. The main greenhouse gas, carbon dioxide, remains in the atmosphere for almost 100 years, so past and present human action will affect future generations.

In the 2000s, the EPA collected information on pollution and greenhouse gas emissions, or gases released into the air. It also encouraged energy conservation and the development of cleaner energy. The EPA worked to reduce greenhouse gas emissions. Since both pollution and climate change were global issues, the EPA also worked with international partners.

Analyze Images The water level of Lake Mead, shown here, has dropped significantly due to drought.

Draw Conclusions How might climate change affect your environment?

Progress on Cleaner Energy

To reduce greenhouse gas emissions, the U.S. government encouraged the use of renewable energy sources. Unlike fossil fuels, renewable energy sources have potentially unlimited supplies. Energy from the sun, wind, moving water, Earth’s heat (geothermal energy), and organic plant and waste material (biomass) can restore itself.

Environmentalists preferred these energy sources to fossil fuels. They had the potential to decrease America’s dependence on foreign oil, diminish greenhouse gas emissions, and reduce pollution. Critics argued, however, that these sources are often more expensive than fossil fuels and that relying on them could harm the economy.

Nuclear power and biofuels provided additional alternatives to fossil fuels. The dangers of nuclear power made it controversial, though. In 1979, the Three Mile Island nuclear power plant near Harrisburg, Pennsylvania, experienced a meltdown in its reactor. This accident caused radioactive material to leak and forced people to evacuate. Radioactive material is harmful and can be deadly to people and other living things.

Nuclear power plants convert radioactive nuclear fuels into energy by capturing the force of splitting atoms. This process leaves behind nuclear waste, or radioactive material. Nuclear waste remains hazardous to people and other living things for hundreds of thousands of years. During the early 2000s, experts could not agree on a safe way to dispose of nuclear waste, so there was the risk that it could harm people for many generations to come.

Biofuels are alternative energy sources produced from converting biomass, plant, and waste material into liquid fuels. The most common forms of biofuels are ethanol and biodiesel. During the early 2000s, most ethanol in the United States was produced from corn. Beginning in 2005, federal law required a percentage of the gasoline sold in the United States to be mixed with at least small quantities of ethanol. Biodiesel is produced from crops such as soybeans. Both fuels can power automobiles.

Biofuels, however, were also controversial. Growing, processing, and transporting crops to create biofuels uses fossil fuels that contribute to pollution and consume energy. There were questions about whether the energy that biofuels produce was greater than the energy used to create the biofuels themselves. Critics also noted that using crops for fuel could increase food costs.

Analyze Images Solar farms trap energy from the sun. That energy is later converted into electricity that people can use.

Compare and Contrast how using solar energy and burning fossil fuels change the environment.

READING CHECK

Identify Supporting Details Name two reasons why environmentalists prefer renewable energy sources to fossil fuels.

A Networked World

Computers allow information to be saved, analyzed, and exchanged. The first computers in the world were mainframes, which were so large they could fill a room. In the 1950s and 1960s, only private businesses, the government, and universities could afford to own them. By the 1980s, affordability and smaller sizes made personal computers common in homes, small businesses, and schools. By the early 2000s, new technology had made computers faster, less expensive, and more portable. Some computers could fit in a pocket.

Analyze Visuals Early computers, such as this IBM “702” model from 1954, were so large they had to be housed in an entire room.

Draw Conclusions What might be the purpose of the object the man on the right of the photo is holding in his hand?

The Internet

In the 1960s, a scientist at the Massachusetts Institute of Technology worked to develop a system to connect computers worldwide. His ideas provided the basis for the Internet, a system of linking computers that gives users access to information. In 1969, the United States Department of Defense began linking its computers to computers at American universities. In the 1990s, private companies made the Internet available to homes and businesses.

The Internet makes email communication, instant messaging, Voice over Internet Protocol (VoIP) calls, video calls, and use of the World Wide Web, often simply known as the Web, possible. The Web was created in the 1980s using technology developed by the United States, Britain, and France.

Although sometimes lumped together, the Web and the Internet are not the same. The Web is one of many services that run on the Internet. It links documents through hypertext. Web browsers let people view those documents as images, texts, and multimedia on the Internet.

Personal computers and the Internet changed the world. They increased business productivity and efficiency. E-commerce expanded the marketplace to make it digital and global. People regularly bought products, paid bills, and managed their bank accounts online. Digital lessons, textbooks, and library resources transformed teaching and learning.

The Internet and the Web introduced users to social networking. Social networks allow people with shared interests and backgrounds to connect digitally. Social network sites can be used for personal and business connections. They allow people to set up profiles and manage who has access to the information that they share.

Like the rest of the Internet, social networking sites presented risks when they did not adequately protect individual privacy. They also could be vulnerable to data theft and viruses.

The Mobile Revolution

The first mobile phones were developed in the 1970s, but they were awkward and expensive. Mobile phones came into wider use in the 1990s.

By the early 2000s, many Americans owned smart phones, or small, handheld phones with sophisticated computing capability and an ability to connect to the Internet via radio signals. Many individuals and families also owned tablet computers. Tablets are small mobile computers with touch screens that also connect to the Internet.

Mobile devices such as smart phones and tablets use application software, or apps, to operate. Originally, apps were used for simple tasks like sending and receiving email, managing a calendar, or collecting contact information.

Public demand led software engineers to develop apps for games, magazines and books, banking, and shopping. Today, Americans use apps for social networking, viewing videos, searching for information, and reading books.

In spite of their popularity, mobile devices raised some concerns. Phone use in cars led to accidents. Many states required people to use hands-free devices while driving. People often found cell phone use disruptive in places such as restaurants, stores, and on public transportation. Smartphones contain chemicals that are toxic to humans and animals. The production and improper disposal of mobile devices damaged the environment.

Analyze Graphs Since the turn of the century, cell phone use has increased significantly.

Use Visual Information Which country has made the greatest jump in cell phone ownership since 2002?

Digital Security

As use of the Internet and the Web increased, concern over cybercrime increased with it. Cybercrime includes identity theft, or collecting information about a person in order to engage in illegal activity.

Many cybercriminals make fraudulent purchases with the information. Cybercrime also includes espionage and illegal intelligence gathering.

“Hackers,” who tap into computers and threaten privacy, contribute to the spread of cybercrime. Today, most Internet attacks take place through computers based in the United States, China, and Russia.

Cyberwarfare is a digital form of warfare. It uses computers and other digital devices to attack an enemy’s information system. It can be used in combination with military-based attacks, or it can be carried out on its own. Cyberwarfare can be directed toward businesses, agencies, organizations, and governments.

Politics or terrorism often motivate cyberattackers. If a cyberattack hit a country’s power grid, it could cause traffic accidents, interrupt surgeries, and stop factory production.

During the 2000s, the Department of Defense’s cyberwarfare unit and the National Security Agency (NSA) worked to protect the United States from cyberattacks. The NSA collected and processed data to protect the security of the nation.

Some of the NSA’s data collection methods were controversial. In 2013, NSA contractor Edward Snowden leaked NSA documents to the press. Snowden’s actions were also controversial. The U.S. government charged that he had damaged the nation’s security. The case raised questions about government surveillance of U.S. citizens and American allies and the balance between individual privacy and national security.

Analyze Political Cartoons Internet attacks threaten both personal privacy and international security.

Identify Implied Main Ideas What is the cartoonist’s message about the potential effects of technology on the United States?

READING CHECK

Understand Effects What concern do many people share about social networking sites?