The Swedish environmental activist Greta Thunberg (holding sign) marches in a 2019 protest organized by students. As a teenager, Thunberg became known for her boldness in confronting adult politicians for their inaction on climate change due to global warming.
Credit: © Alexandros Michailidis, Shutterstock

This Saturday, April 22, is Earth Day, an annual observance to increase public awareness of environmental issues. Each year on Earth Day, millions of people throughout the world gather to clean up litter, protest threats to the environment, and celebrate progress in reducing pollution.

Earth Day began in the United States. In 1969, the U.S. Senator Gaylord A. Nelson suggested that a day of environmental education be held on college campuses. The following year, the lawyer and environmentalist Denis Hayes, then a recent graduate of Stanford University, led hundreds of students in planning and organizing the observance of Earth Day on April 22, 1970. About 20 million people participated in this celebration.

The observance of Earth Day in 1970 helped alert people to the dangers of pollution and stimulated a new environmental movement. That same year, Congress created the Environmental Protection Agency to set and enforce pollution standards. Congress also passed the Clean Air Act of 1970, which limited the amount of air pollution that cars, utilities, and industries could release. Other new environmental laws soon followed.

One modern champion for the environment is the Swedish activist Greta Thunberg. She has worked to convince politicians to take action against climate change due to global warming. Global warming is an observed increase in Earth’s average surface temperature. As a teenager, Thunberg became known for her boldness in confronting adult politicians for their inaction on climate change. She has called upon leaders to reduce emissions of greenhouse gases, mainly carbon dioxide. Such gases trap heat in the atmosphere, warming the planet’s surface.

Thunberg was born in Stockholm, Sweden, on Jan. 3, 2003. She was diagnosed with autism spectrum disorder at a young age. As a child, she showed an interest in environmental issues. She convinced her family to reduce their carbon footprint by becoming vegan and giving up air travel. Carbon footprint is a measure of the greenhouse gas emissions associated with human activities.

In 2018, at the age of 15, Thunberg protested for action on climate change outside the Swedish parliament, inspiring other student protesters. Together, they organized school strikes to demand action on climate change. In August 2019, Thunberg sailed across the Atlantic Ocean from Plymouth, in the United Kingdom, to New York City, in the United States, on a “carbon neutral” voyage. Thunberg sailed aboard a yacht that got its electric power from solar panels and underwater turbines. While in the United States, she addressed the United Nations as part of its Climate Action Summit. During her speech, she announced that she and a group of other children were filing a lawsuit against five nations not on track to meet their emission-reduction targets under the Paris Agreement. The Paris Agreement is a global treaty designed to fight global warming.

Thunberg is the author of several books on climate change activism. No One Is Too Small to Make a Difference (2019) is a collection of Thunberg’s speeches. Our House Is on Fire (2020), a memoir by Thunberg and her family, tells how Thunberg’s personal struggles led her to become an activist. Thunberg’s best seller The Climate Book (2023) explains how the climate is changing and calls on society to adopt effective strategies to slow climate change.

Beekeepers wear protective veils. Light-colored clothes help provide protection from stings. A few experienced beekeepers handle the bees and honeycombs with their bare hands.
Credit: © Shutterstock

You may have heard the phrase “Save the bees” before, but a vaccine for bees? That is something new! Honeybees in the United States have faced diseases and pests that have decimated the population. Bees are important and affect our daily lives. Bees pollinate plants and flowers, giving us food, medicine, and of course, pretty flowers. Recently, scientists at the Dalan Animal Health based in Athens, Georgia, created a vaccine to save the bees for real!

What is the vaccine for? We know about vaccines for the flu and COVID-19, this vaccine protects bees against American foulbrood. Since American foulbrood is caused by bacteria, the scientists figured out how to put the dead bacteria in the vaccine. When American foulbrood infects a hive, it causes the larva to be darker and gives the entire hive a rotten smell. American foulbrood can spread from hive to hive, wiping out colonies of 60,000 bees.

How do the scientists give the bees the vaccine? No, it isn’t a shot, and they will not have to invent little bandaids for the bees. The scientists put the dead bacteria into royal jelly, which is a sugar feed the queen bees eat. This process exposes the queen bee’s future offspring to the bacteria so the bees can make antibodies. Antibodies are proteins that help the immune system fight off bacteria and viruses.

A typical honey bee colony may include tens of thousands of workers. This photograph shows workers tending to honey stored in the cells of a honeycomb.
Credit: © StudioSmart/Shutterstock

Honeybees are important. They are vital to agriculture around the world. Without bees, the world would deal with more food scarcity. During their food-gathering flights, bees spread pollen from one flower to another, thus pollinating (fertilizing) the plants they visit. This allows the plants to reproduce. Numerous wild plants and such important food crops as fruits and vegetables depend on bees for fertilization. Honeybees pollinate nearly one-third of all food crops grown in the United States. Popular crops like almonds, apples, cherries, and pears require pollination from bees. Nearly three-quarters of all flowering plants rely on pollination from bees and other pollinators like butterflies and moths.

American foulbrood isn’t the only bee enemy. Bees are also declining in population due to climate change, disease, habitat loss, and pesticides. Beekeepers have given entire hives antibiotics to fight off diseases. However, the use of antibiotics can decrease beneficial bacteria and weaken the bees. Animals, mites, and human activities all threaten bees worldwide. There is also a disorder called Colony Collapse Disorder (CCD), an unusual condition that destroys hundreds of thousands of honey bee colonies each year in the United States. While the vaccine protects against American foulbrood, bees are also in danger of dying from European foulbrood. Diseases caused by fungi, such as Nosema disease, are also a threat to bees. Scientists hope the success of this vaccine will lead to others protecting the future of the bees!

Humpback whale mother and calf
Credit: © Shutterstock

A study published in November 2021 reported more accurate measurements of just how much giant whales eat—and just how much they defecate (eliminate solid wastes)—which has surprising effects on the ocean ecosystem and even global climate. The research demonstrates that ocean food webs are more complex and intertwined in surprising ways, more surprising than simple predator-prey relationships.

Baleen whales, including the blue whale, bowhead whale, fin whale, and right whale, are among the largest animals that ever lived. These gigantic beasts feed mainly on millions of tiny shrimp-like krill and other zooplankton that they filter out from huge gulps of seawater. Calculating exactly how much they eat has always been a difficult exercise.

A gray whale filters food from water by squeezing the water out of its mouth through thin plates called baleen.
Credit: © Shutterstock

In the latest study, scientists used Global Positioning System (GPS) tags to follow more than 300 baleen whales as they swam and ate their way through the oceans. This tracking enabled the scientists to record each time a whale lunged to gulp a mouthful of krill. Sonar and drones flown overhead were used to determine the dimensions of the krill swarm swallowed, providing the most accurate measure yet of how much each whale was consuming. The results were surprising. The baleen whales were routinely eating three times or more the amount of food previously estimated. Across all species studied, baleen whales consume an average of 5 to 30 percent of their body weight each day. A single average-weight adult blue whale can consume about 40 million krill a day, equaling about 4 tons (3.6 metric tons). Of course, what goes in must come out. So equally astonishing was the amount of feces (solid bodily waste) that baleen whales produce as measured by the study. A blue whale can excrete more than 50 gallons (190 liters) of waste in one go.

The populations of many kinds of whales collapsed in the 1900’s because of excessive whaling. Whalers killed so many blue, bowhead, humpback, and right whales that these species nearly became extinct. The researchers estimate that before the 1900’s, baleen whales in the Southern Ocean consumed 430 million tons (390 million metric tons) of krill annually. That’s twice as much krill than exists today. With so many krill-eating whales removed from the ecosystem, researchers expected krill populations to increase. But krill populations dropped after most of their predators were killed off—a fact known among ocean scientists as the krill paradox.

How could this have happened? Researchers know when whales feed on krill, a good amount of nutrients are excreted in their feces afterward. In the nutrient-poor Southern and Pacific oceans, this cycling of nutrients is especially important. The nutrients excreted are rapidly taken up by blooming populations of simple one-celled algae in the oceans called phytoplankton. The phytoplankton in turn serve as food for more krill, which are then food for whales. More whales mean more whale poop—fertilizer in the ocean—which means more krill.

When living things grow, they add carbon to their bodies, removing some carbon from the atmosphere. In another unexpected finding, the researchers estimate that restoring baleen whale populations to 1900 levels could foster plankton blooms that would remove 235 million tons (215 million metric tons) of carbon from the atmosphere, helping to combat global warming.

January 13, 2020

Earth has been a particularly dangerous place in recent weeks. Airplane crashes, military clashes, terror attacks, and political unrest have taken a toll on human life and happiness lately, but it is a series of natural disasters that has caused the most trouble. A typhoon ravaged the Philippines, deadly flash floods hit Indonesia, bushfires continued to rage in Australia, a measles epidemic continued to kill in the Democratic Republic of the Congo, and a series of earthquakes rattled Puerto Rico.

Firefighters confront a bushfire near the Blue Mountains town of Bilpin, New South Wales, on Dec. 19, 2019. Credit: © 1234rf/Shutterstock

On Christmas Eve and Christmas Day Typhoon Phanfone (also called Ursula) struck the Philippines, producing high winds and flooding that killed 105 people in the Visayan Island provinces of Biliran, Capiz, Iloilo, and Leyte. Phanfone was a Category 2 storm (moderate strength) with sustained winds of more than 90 miles (150 kilometers) per hour. Storm surges and deadly flash floods hit communities just as families were gathering to celebrate the Christmas holiday. Thousands of homes were damaged or destroyed.

On New Year’s Day in Indonesia, abnormally heavy monsoon rains caused flash floods that killed 66 people and displaced hundreds of thousands of others in Jakarta, the capital. Some 14.5 inches (37 centimeters) of rain fell on New Year’s Eve, causing the Ciliwung and Cisadane rivers to overflow. Floodwaters submerged more than 150 neighborhoods and caused landslides in the Bogor and Depok districts on the outskirts of Jakarta. Flood water levels in some areas peaked at more than 13 feet (4 meters). Electric power was cut off, and closed schools and government buildings were converted into emergency shelters.

On January 7, the World Health Organization announced the 6,000th death from measles in the Democratic Republic of the Congo (DRC) since an epidemic began there in 2019. More than 300,000 suspected measles cases have been reported in the DRC—a nation also troubled by recent terror attacks. The epidemic has continued and grown because of low vaccination coverage, malnutrition, weak public health systems, outbreaks of other epidemic-prone diseases (such as Ebola), and the difficulty of getting health care to people in remote areas.

In Puerto Rico, after several smaller earthquakes, a 6.4-magnitude temblor struck the southwestern part of the island on January 7. The earthquake, the strongest to hit Puerto Rico in more than 100 years, killed one person, toppled hundreds of structures, and forced a state of emergency. Many people lost their homes, the island briefly lost electric power, and schools and public offices were closed. In the 10 days before the 6.4-magnitude earthquake, the United States Geological Survey recorded hundreds of temblors in Puerto Rico—including 10 of 4-magnitude or greater.

A number of major bushfires have lately devastated southeastern Australia. Since September, the wild fires—mostly in New South Wales, Queensland, and Victoria—have burned more than 25.5 million acres (10.3 million hectares), an area the size of South Korea. The bushfires have destroyed more than 2,100 homes and killed 27 people and hundreds of millions of animals. On January 8, the Australian government ordered the mass slaughter of thousands of wild camels and horses that have invaded rural towns looking for water. Many people are without electric power and telecommunications in Australia’s southeast, and some were without drinking water and other supplies. Smoke has obscured the city skies of Canberra, Melbourne, and Sydney. The bushfires followed a three-year drought that experts link to climate change.

December 23, 2019

Saturday, December 21, was the winter solstice in the United States and the rest of the Northern Hemisphere. In the Southern Hemisphere—which includes Australia, New Zealand, and other lands south of the equator—the solstice marks the beginning of summer. In Australia, summer is a season known for bushfires. Such wildfires are common in Australia, due in part to the country’s hot and dry climate. Many wildfires start in the remote countryside known to Australians as the bush. Bushfires can be extremely destructive, especially if they reach urban areas. The fires often kill people and destroy property and farmland. They also devastate forests, along with the koalas and other animals that live there.

Police in Jimboomba, Queensland, rescued this koala and her joey from a bushfire in late November 2019. Many other koalas were not so lucky. Credit: Jimboomba Police

A number of major bushfires have plagued Australia in 2019. Late last summer, in February, bushfires consumed more than 50,000 acres (20,000 hectares) of land in northern New South Wales. Far more destructive bushfires ignited again in New South Wales in September, burning nearly 5 million acres (2 million hectares) there and in neighboring Queensland. Some of those fires lasted for weeks, while others continue to burn, turning skies black or orange, causing severe damage, and killing a number of people. The bushfires also killed thousands of vulnerable and slow-moving koalas trapped by the rapidly spreading flames.

Bushfires are relatively common in Australia. These fire-damaged buildings are seen alongside a house that survived Christmas Day bushfires near Melbourne in 2015. Credit: © Julian Smith, EPA/Landov

Koalas live only in the forests of Queensland, New South Wales, and Victoria, in eastern Australia. They are found in significant numbers in only a few areas, and the animals are protected by law. Bushfires, however, ravage the koala’s natural habitat and its population. Koalas cannot escape the fast-moving fires, and their only defense is to climb to the top of a tree, curl into a ball, and hope the flames do not rise to reach them. Koalas sometimes survive this way, but they often burn their paws and claws descending charred trees, leaving them unable to climb properly again.

Koalas are not officially listed as endangered, but the population in New South Wales and Queensland has decreased by more than 40 percent since 1990. The animals are threatened by deforestation and habitat loss, as well as the effects of climate change, which is causing longer and more intense heat waves and droughts, leading to more frequent, intense, and longer-lasting bushfires. Beyond the flames and smoke of the fires, many koalas die from lack of water or exposure to prolonged periods of high temperatures. Australia just suffered through the driest spring in its history, and a brutal heat wave peaked on Dec. 19, 2019, when the highest ever nationwide average temperature—107.4 °F (41.9 °C)—was recorded.

October 2, 2019

In the Netherlands, the largest bicycle parking facility in the world recently opened in the city of Utrecht. The underground Fietsenstalling Stationsplein (Bicycle Parking Station Square), in Utrecht’s city center, has space for 12,500 bikes. Double-decker racks hold thousands of bikes in a three-storied concrete and glass garage, and riders pedal directly into the building and up to their parking spaces. Part of the building opened in 2018, but the fietsenstalling did not reach its full operational capacity until August 2019.

A man parks his bicycle at the Fietsenstalling Stationsplein in Utrecht on Aug. 20, 2019. Credit: © Abdullah Asiran, Anadolu Agency/Getty Images

Bicycling, or fietsen in Dutch, is a popular activity and sport in the Netherlands, but it is also a practical mode of daily transport. In Dutch cities, about 40 percent of people use bikes for daily travel (as opposed to fewer than 2 percent of people in United States cities). To accommodate all those bike commuters, Dutch cities have an abundance of bike lanes in the streets, protected intersections, special bike paths away from car traffic, and numerous bicycle parking areas. Utrecht has long had such “bike friendly” infrastructure (the world’s first bike lane opened there in 1885), but to handle the ever-increasing bike congestion in the city center, a more ambitious solution was needed.

The city of Utrecht worked with NS, the national Dutch railway, to build the bike garage at Stationsplein (Station Square). (NS [Nederlandse Spoorwegen, or Dutch Railways] estimates that about half its customers in Utrecht arrive at stations by bicycle, so it makes sense for the railway to accommodate bike commuters.) Stationsplein connects the busy Utrecht Centraal Railway Station with the Hoog Catharijne shopping center. The bustling area is a common destination for both shoppers and commuters, and the bike garage—directly beneath the square—provides an affordable and secure place to leave your bike. The first 24 hours of parking are free, and the garage never closes. A digital system directs cyclists to available parking spots, and the walls are color coded to aid in navigation. There are also bike maintenance areas in the facility and more than 1,000 bikes available to rent.

Adding to the bicycling infrastructure in the Netherlands is an important part of the nation’s commitment to fighting air pollution and climate change. Bicycling is a healthy, inexpensive, and environmentally friendly way to commute.

September 6, 2019

This summer, unusually warm air temperatures have caused record ice melt in the North Atlantic Ocean island of Greenland. During the month of July alone, the island lost more ice than it normally does in an entire year. In just a five-day period, from July 30 to August 3, the island lost about 90 percent of the surface of its ice sheet (a massive glacier)—an estimated 55 billion tons (50 billion metric tons) of ice. The record ice loss is a result of global warming and climate change.

A Danish meteorological team travels across submerged sea ice in Greenland’s Inglefield Bredning fjord on June 13, 2019. The area is normally covered with ice and snow. Credit: Steffen M. Olsen, Danish Meteorological Institute

At the highest point of the Greenland Ice Sheet, 10,550 feet (3,216 meters) above sea level, temperatures topped freezing (32 °F or 0 °C) for more than 16 hours during July 30 and 31, melting some 12.5 billion tons (11.3 billion metric tons) of ice during that brief period. It was the first time ice had melted at that high point since July 2012, and it was just the third such ice melt there in the last 700 years.

Click to view larger image. Greenland, a self-governing territory of Denmark, stretches from the Arctic to the North Atlantic Ocean. Credit: WORLD BOOK map

The ice sheet that covers Greenland is about the size of Alaska, and it contains enough ice to raise global sea levels by more than 20 feet (6 meters). During an average summer, Greenland will lose some ice from meltwater and from icebergs that calve (break off) into the ocean. But the ice loss typically happens at the sheet’s edges at sea level—not at the highest and coldest points. The amount of ice loss is also normally much less. From 1981 to 2010, the average ice melt from July 30 to August 3 was 15 billion tons (13.6 billion metric tons).

Huge icebergs form where the Jakobshavn Glacier flows into the sea near Ilulissat, Greenland. Credit: © Radius Images, Getty Images

The drastic summer ice melt in Greenland is a continuation of an alarming and worsening trend. In 1972, Landsat satellites (a project then known as the Earth Resources Technology Satellite) began photographing and mapping Greenland’s ice sheet. Landsat, a joint mission of NASA and the United States Geological Survey, uses a series of satellites to produce detailed images of Earth from space.

From 1979 to 2006, satellite images showed a 30 percent rise in the amount of Greenland ice that melts each summer, and the ice loss continues to increase. Greenland’s ice fronts have drastically retreated, rocky peaks have become exposed, and the size and shape of the island’s many fiords have changed significantly. In August 2019, Landsat images showed wet snow and melt ponds at Greenland’s higher elevations, and large parts of the island’s shrinking glaciers appeared brownish grey. The color indicates that the surface has melted, a process that concentrates dust and rock particles and leads to a darker recrystallized ice sheet surface.

Greenland is not the only site of rapidly increasing ice melt. Warmer global temperatures are reducing glaciers and ice fields in the Arctic and Antarctica, as well as in Iceland, the Alps, the Andes, the Himalaya, the Rockies, at Kilimanjaro in Tanzania, and in the Sudirman Range in Indonesia.

August 16, 2019

Throughout 2019, a controversial movement known as the Extinction Rebellion has been making headlines around the world. The Extinction Rebellion is an international movement that advocates nonviolent civil disobedience (see the detailed explanation below) to pressure governments into taking action on climate change and the mass extinction of animal species. The movement, spurred by the negative effects of global warming and habitat loss, began in the United Kingdom in 2018, and it has since spread to Australia, Canada, France, Ireland, New Zealand, Norway, Spain, the United States, and other countries. The stated goal of the group is to preserve Earth for all living things.

Extinction Rebellion activists gather before the prime minister’s office in London, England, on March 9, 2019. Credit: © Sandor Szmutko, Shutterstock

In its own words, the Extinction Rebellion (sometimes referred to as XR) is attempting “to halt mass extinction and minimize the risk of social collapse.” The group wants governments to work to halt biodiversity loss and reduce greenhouse gas emissions. The WWF (formerly the World Wildlife Fund) reports that animal populations have decreased by 58 percent in the last 50 years, mainly due to habitat loss. The widespread loss of animals has a corresponding detrimental effect on human populations. And carbon dioxide and other greenhouse gases produced by the burning of fossil fuels are the leading causes of global warming. The XR also asks individual citizens to lead healthier and environmentally responsible lives.

The Extinction Rebellion began in October 2018, when climate activists gathered for a “Declaration of Rebellion” in London’s Parliament Square. The movement quickly grew and spread to other parts of the world where existing climate action groups gathered under the circled hourglass extinction symbol banner. Major Extinction Rebellion protests have blocked bridges, roads, and public transportation, and they have disrupted government, media, and petroleum company offices. Because their actions are often unlawful, the group is somewhat controversial, and many XR activists have been arrested.

Credit: © Extinction Rebellion

Civil disobedience is the deliberate and public refusal to obey a law. Some people use civil disobedience as a form of protest to attract attention to what they consider unjust or unconstitutional laws or policies. They hope their actions will move other people to correct the injustices. Other people regard civil disobedience as a matter of individual religious or moral conviction. They refuse to obey laws that they believe violate their personal principles.

Throughout history, there has been widespread disagreement concerning the use of civil disobedience in a society based on law and order. Some people claim that citizens are obligated to disobey laws they consider unjust, for example laws segregating the races. They say that such lawbreaking may be the best way to test the constitutionality of a law. Some defend the use of civil disobedience by pointing to laws widely considered unjust or immoral, such as Nazi Germany’s laws calling for extermination of Jews and other groups. Other people claim that it is never right to break a law deliberately. They argue that defiance of any law leads to contempt for other laws. Any act of civil disobedience, they believe, weakens society and may lead to violence and anarchy (the absence of government or law).

Famous practitioners of civil disobedience include the writer Henry David Thoreau, the suffragist Susan B. Anthony, and Mohandas K. Gandhi of India. In the United States, during the 1950′s and 1960′s, Martin Luther King, Jr., and other civil rights workers deliberately violated Southern segregation laws as a means of fighting racial injustice. Many opponents of the Vietnam War (1957-1975) committed various illegal acts in attempts to change U.S. policy. Some refused to pay their taxes. Others refused to register for the draft. During the 1980′s, nonviolent protests were directed at the repressive racial policy of apartheid (segregation) of the minority white government in South Africa.

August 5, 2019

Last week, on July 29, in the northeastern African nation of Ethiopia, citizens worked with conservation groups, business leaders, and the government to plant more than 350 million trees in a single day. Part of Ethiopia’s Green Legacy Initiative to combat deforestation and climate change, the highly organized event resulted in the planting of 353,633,660 seedlings in just 12 hours. Believed to be a world record, the number far exceeded the original goal of planting 200 million trees in one day. The Green Legacy Initiative hopes to brighten the ecological future of a nation prone to such climate-related problems as drought, famine, and soil erosion.

Prime Minister Abiy Ahmed plants one of more than 350 million trees planted in Ethiopia on July 29, 2019. Credit: Office of the Prime Minister

For the record tree-planting day, many schools and government offices were closed to allow more people to participate. Ethiopian Prime Minister Abiy Ahmed joined in the effort, planting trees in the capital city of Addis Ababa. The tree-planting drive targeted areas that have been stripped of forests over the years, and the types of new trees varied from region to region. The United Nations estimates that just 4 percent of Ethiopia is currently covered by forest, down from about 30 percent in 1900. Ethiopia’s ever-growing population, the need for more farmland, unsustainable forest use, and climate change are cited as the major causes for the nation’s drastic deforestation.

Illinois Senator (and future United States President) Barack Obama plants a tree in Uhuru Park in Nairobi, Kenya, with environmental activist and Nobel Peace Prize winner Wangari Muta Maathai in 2006. Every tree planted helps counteract the effects of climate change. Credit: © Green Belt Movement

The Green Legacy Initiative, launched in May 2019, aims to help reverse Ethiopia’s environmental decline by providing tree seedlings, encouraging tree-planting groups, and asking every citizen to plant at least 40 trees by the end of October. (The seedlings have a better chance of surviving in Ethiopia during the wetter months from May to October.) With a population of about 114 million people, this puts the initiative’s goal at more than 4 billion newly planted trees. More than 2.6 billion trees have been planted so far. Aside from ordinary counting methods, the Ethiopian government is using satellites and special computer software to keep track of the immense number of planted seedlings. The Green Legacy Initiative is also cleaning waterways and making agriculture more sustainable.

The planting of carbon dioxide-absorbing trees—along with recycling and reducing the use of plastics, fossil fuels, and other environmentally damaging materials—is a highly effective way to counteract the effects of global warming and climate change. India set the previous world record for the most trees planted in one day (50 million) on July 11, 2016.

July 17, 2019

To help reduce pollution in the United States, a Sierra Club program called “Ready for 100” is encouraging communities and individuals to commit to the use of 100 percent renewable energy sources. The Sierra Club, founded in 1892 by the naturalist John Muir, is an organization that works to protect the environment. Ready for 100 is asking business, civic, community, and religious leaders, as well as families and students, to help achieve the goal of complete nationwide reliance on clean, renewable energy by the year 2050.

Renewable energy comes from such sources as the sun, wind, moving water, heat beneath the ground, and plants. Such energy sources are considered “clean” because they cause little or no pollution, and they differ from fossil fuels such as coal, oil, and natural gas. Burning fossil fuels causes air pollution and acid rain, and also releases large amounts of carbon dioxide and other greenhouse gases. The gases trap heat in Earth’s atmosphere, contributing to global warming and climate change.

Since November 2016, solar panels and battery systems have provided 100 percent of the energy needed to power the island of Ta’u, seen here, in the U.S. Pacific territory of American Samoa. Credit: © SolarCity

There are many benefits to using clean energy sources. They can provide communities with cleaner air and water, lower energy costs, greater energy independence, and greater local ownership of energy systems. More than 50 nations around the world, including Brazil, Canada, and Norway, already get more than 50 percent of their energy supply from renewable sources. Costa Rica expects to be using 100 percent renewable energy by 2021. The U.S. state of Hawaii has promised to be Ready for 100 by 2045, and recent California legislation requires the country’s most populous state to achieve 50 percent renewable energy use by 2030. Such worldwide cities as Munich, New York, and Sydney are also well beyond the 50 percent mark, and they are fast approaching total reliance on renewable energy. To reach 100 percent, the amount of energy generated from renewable sources (for such uses as electric power, heating and cooling, and transportation) must equal or exceed the annual energy consumed.

Hoover Dam on the Colorado River has been providing renewable hydroelectric energy in the southwestern United States since 1935. Credit: U.S. Department of Transportation

So far, 182 U.S. towns and cities from coast to coast have committed to 100 percent renewable energy use by 2050. Aspen, Colorado (since 2015); Burlington, Vermont (2014); Georgetown, Texas (2018); Greensburg, Kansas (2013); Kodiak Island, Alaska (2012); and Rock Port, Missouri (2008) have already hit the 100 percent renewable energy mark, leading the push for cleaner energy and a healthier future.