August 3, 2018

For many people in the Northern Hemisphere, the summer of 2018 has been touched by fire and obscured by smoke. Summers are typically fire seasons in many areas, but climate change has caused hotter and drier conditions in recent years, and wildfire outbreaks have become more frequent and more destructive. Other causes of increased fire activity include the building of more developments in fire-prone areas, a lack of proper forest management, and, of course, simple human carelessness. In the past weeks, fires have killed more than 100 people and destroyed homes and large swaths of land in Asia, Europe, and North America.

A firefighting helicopter flies over a wildfire in the Greek town of Rafina near Athens on July 23, 2018. The Greek wildfire was the deadliest yet this year, claiming the lives of 92 people. Credit: © Angelos Tzortzinis, AFP/Getty Images

In southeastern Greece, a wildfire erupted July 23, destroying or damaging some 3,500 structures and killing 96 people along the Attica coast. The giant wildfire, just 18 miles (30 kilometers) east of Athens, the Greek capital, burned out of control for several days, gutting seaside resorts and holiday homes. Fanned by high winds, the fast-moving blaze trapped and killed groups of people, including entire families as they huddled between the flames and steep cliffs overlooking the Aegean Sea. The high death toll prompted criticism of the the area’s lack of access roads, warning systems, and other civil protection measures in areas surrounded by forest and at high risk of wildfires.

In far northern Europe, dozens of wildfires have consumed more than 62,000 acres (25,000 hectares) this summer in Sweden, which is experiencing an abnormally lengthy and intense heat wave. Neighboring Finland and Norway are also suffering from unusual heat and wildfire outbreaks, as are Estonia, Latvia, and Lithuania on the other side of the Baltic Sea. Wildfires also torched drought-stricken areas of Germany, the Netherlands, and Poland.

This week in northern California, firefighters continued to battle the Carr Fire that has killed 8 people, destroyed over 1,500 buildings, and consumed some 125,000 acres (50,000 hectares) of land. The wildfire started on July 23 along Carr Powerhouse Road in Shasta County near the city of Redding. The “mechanical failure of a vehicle” ignited dried grasses and trees, and soon flames were roaring through the forested hills around Whiskeytown Lake west of Redding. The wildfire, aided by hot and dry weather, high winds, an abundance of natural fuel, and steep terrain, has since been chased westward by more than 4,200 firefighters—2 of whom have died fighting the blaze. Reports of  “firenados” (huge, rotating whorls of smoke, flame, and ash) encouraged nearly 40,000 people to obey evacuation orders and leave the fire area (which included parts of nearby Trinity County). Many people will return to find their homes and property in ashes.

The Carr Fire is the largest of 17 wildfires currently burning throughout the state of California. Collectively, wildfires in the western United States have scorched 4.6 million acres (1.86 million hectares) so far this year, a 24 percent increase over the annual average for the past decade. Wildfires have also stricken large areas of western Canada and parts of Mexico this summer.

Wildfires have also consumed vast amounts of territory in Siberia of eastern Russia. Since May, firefighters have been battling immense wildfires in the Amur Oblast region along the Chinese border, where towering pyrocumulus clouds have injected smoke and pollutants high into Earth’s atmosphere. Pyrocumulus clouds are formed by rising heat from wildfires or by plume emissions from fossil fuel-burning industrial plants, and they sharply increase the levels of carbon dioxide and harmful aerosols in the atmosphere.

August 27, 2013

Dust particles from the meteor that exploded over the Russian city of Chelyabinsk in western Siberia on February 15 formed a belt that circled the Northern Hemisphere for months, NASA scientists have found. The scientists, working out of the Goddard Space Flight Center in Greenbelt, Maryland, said that within four days of the explosion, the faster, higher part of the belt had encircled the Earth and returned to Chelyabinsk. Although larger pieces of the belt slowly lost speed and altitude over time, small, light particles remained in the stratosphere for at least three months. The scientists mapped the dust belt using data from the NASA-NOAA Suomi National Polar-orbiting Partnership satellite and computer simulations of atmospheric circulation patterns.

The higher faster particles (red) in a dust plume created by the explosion of a meteor over Siberia circled the Northern Hemisphere within only four days. (NASA Goddard's Scientific Visualization Studio)

The meteor, which measured 59 feet (18 meters) across, created a powerful sonic boom as it slammed into Earth’s atmosphere at 41,600 mph (18.6 kilometers per second) and exploded at an altitude of 14.5 miles (23.3 kilometers) above Chelyabinsk. The explosion injured more than 1,000 people and shattered windows, dishes, and television screens over a large area near the city. Numerous videos taken by residents captured the fireball as it blazed across the sky and the ground-shaking shockwave that followed.

Additional World Book articles:

• When Worlds and Comets Collide (a special report)
• What Has Caused Mass Extinctions (a special report)

February 15, 2013

The unexpected explosion of a meteor over Russia today injured more than 1,000 people and shattered windows, dishes, and television screens over a large area near the city of Chelyabinsk in western Siberia. Most of the injured, hundreds of whom had to be hospitalized, were hurt by flying glass. Preliminary reports said the blast also damaged nearly 300 buildings, including 12 schools and 6 hospitals. The meteor apparently was not related to an asteroid known as 2012 DA14 that is being tracked as it makes a close approach to Earth today.

Scientists from the Russian Academy of Science said the meteor entered Earth’s atmosphere at a speed of at least 33,000 miles (53,000 kilometers) per hour. The object, which may have weighed 10 tons (9 metric tons), created a powerful sonic boom as it slammed into the atmosphere and exploded at an altitude of about 20 to 30 miles (32 to 48 kilometers). Numerous videos taken by residents captured the fireball as it blazed across the sky and the ground-shaking shockwave that followed. Some scientists suggested that the impactor was not a single meteor but a meteor shower.

Russian officials mobilized at least 10,000 police officers and others to search for pieces of the meteor in the area around Chelyabinsk. The city, which is about 930 miles (1,500 kilometers) east of Moscow, has many defense plants, including some for the manufacture of thermonuclear weapons.

A meteor appears in the sky when an object called a meteoroid enters the atmosphere from space. (World Book illustration by Greg Maxson)

The appearance of the meteor near Chelyabinsk recalled one of the most famous meteor events in modern times–the 1908 Tunguska explosion over central Siberia. The object in that event, which scientists believe also exploded in the atmosphere, left an area roughly 30 miles in diameter of flattened and scorched trees.

Asteroid 2012 DA14 was expected to pass by Earth at about 2:25 p.m. Eastern Standard Time. It will make its closest approach to Earth over the eastern Indian Ocean, off  the island of Sumatra. NASA officials have assured the public that this asteroid will not impact Earth. But a NASA spokesperson also said that if another asteroid about the size of 2012 DA14 were to crash into Earth, the result would be “regional devastation.” 2012 DA14 is being monitored by scientists from the Near-Earth Asteroid Tracking Program, established by NASA and the Jet Propulsion Laboratory in Pasadena, California. The agency is trying to detect within 10 years most of the Earth-approaching asteroids larger than 0.6 mile (1 kilometer) in diameter. An estimated 1,000 to 2,000 of these bodies are thought to exist, though scientists have discovered only 861 so far.

Additional World Book articles:

• Dawn
• Eros
• Vesta
• When Worlds and Comets Collide (a special report)
• What Has Caused Mass Extinctions (a special report)

October 1, 2012

The United States and Russia have agreed to preserve the Ice Age heritage of Beringia, an area that includes parts of northeastern Asia and northwestern North America and a land bridge that once connected them. During a recent visit to Russia, U.S. Secretary of State Hillary Rodham Clinton agreed with Russian Foreign Minister Sergei Lavrov to establish the Transboundary Area of Shared Beringian Heritage, a specially protected region that includes the Bering Strait and adjacent areas of Siberia and Alaska. Known as Beringia, this area is home to Inuit and Yuit peoples, who have a common language and traditions but are separated by international borders. A wide range of animals, including polar bears, whales, seals, and walruses, also live there.

At the Bering Strait in the northern Pacific Ocean, the United States and Russia are separated by about 50 miles (80 kilometers) of open water. But during the most recent ice age, huge glaciers covered much of the northern half of Earth and sea level was much lower than it is today. As a result, much of the Bering Strait was a vast stretch of dry land forming a bridge about 1,000 miles (1,600 kilometers) wide at its greatest extent that connected what are now Siberia and Alaska. Most scientists think the first American Indians, following the animals that they hunted, wandered across this harsh environment into North America at least 15,000 years ago. By 12,500 years ago, Indians had spread throughout the New World and were living from the Arctic in the north all the way to what became known as the Strait of Magellan in southern South America.

The Bering Stait is a narrow waterway that connects the Bering and Chukchi seas. (World Book map)

The Transboundary Area of Shared Beringian Heritage formally recognizes the symbolic links between the people and governments of Asia and North America. The new heritage area will aid conservation efforts in this natural ecosystem and promote international cooperation on scientific research and monitoring the enviroment. The new area will formally link two national parks in Alaska–the Bering Land Bridge Natural Preserve and the Cape Krusenstern National Monument–with the newly designated Beringia National Park in Chukhotka, Russia. The region will cover a total of about 7.2 million acres (2.9 million hectares).

United States President George H. W. Bush and Soviet President Mikhail Gorbachev first announced plans to create a transnational park spanning the Bering Strait in 1990, but progress towards the creation of the park stalled. Many components of this new agreement are still being worked out, but officials hope to have a finalized agreement by the end of 2012.

Additional World Book articles:

• Bering, Vitus
• Paleo-Indians
  
• Prehistoric people
• Anthropology (1951) (a Back in Time article)
• The First Americans (a Special Report)

A team of Russian scientists has grown living plants from a flowering plant that died 32,000 years ago. The plant was a type of narrow-leaf campion. Campions, also called catchflies, are a group of flowering plants that have five petals, often cleft or notched (partly divided at the top). Scientists were able to recover fruits of the campion from a squirrel burrow in Siberia, where they had remained frozen for thousands of years. The fruits were collected by an Arctic ground squirrel, which buried them the way modern squirrels do. In this case, the burrow became covered by earth, and the fruits were preserved in permafrost (permanently frozen soil). Scientists recovered the fruits a few years ago and were able to coax cells within them into growing. These cells grew into clones of the long-dead flowers.

Moss campion (far right) is a type of campion that grows in areas too cold and dry for trees to grow. The campion that Russian scientists were able to clone from a frozen seed was a type of Arctic campion. World Book illustration by Kate Lloyd-Jones, Linden Artists Ltd.

The flowers are by far the oldest plants grown from ancient tissue. The previous record was held by a date palm, which was grown from a seed that was 2,000 years old. Seeds usually do not germinate (sprout) after many years.

The scientists tried unsuccessfully to grow flowers from the campion’s seeds. Instead, the researchers were able to grow cells recovered from the fruit. Many plants can grow from tiny parts of a parent, a form of reproduction known as vegetative propagation. The fruits were preserved by the frozen soil. In fact, the fruits were probably frozen shortly after they were buried, because arctic ground squirrels deliberately dig their burrows near frozen soil. In this way, the soil acts as a freezer.

The research will enable scientists to compare the ancient flowers with their living relatives. This work should help scientists understand how the plant has evolved (changed over many generations). The research also raises the possibility that scientists may be able to grow other plants from tissue that has been frozen in soil. It might even be possible to grow plants that have become extinct.

Additional World Book articles:

• Arctic
• Endangered species
• Earth (History of Earth)