Some portions of these ancient aqueducts are still in use. Today, modern, concrete-lined channels transport water hundreds of miles. The most extensive aqueduct systems in the world today are those that bring water to southern California from the Colorado River in the east and from the Sacramento River in the north.
Were the Romans the only civilization to develop water resources in an advanced way?
No, recent excavations in Henan Province in China uncovered a network of clay pipes built during the Eastern Zhou Dynasty (1122 to 256 B.C.E.). The pipes were connected to many reservoirs around the cities, using technology that may actually predate Roman water works.
Where is the biggest hydroelectric dam in the world?
The Three Gorges Dam, which spans the Yangtze River in China’s Hubei Province, is the biggest hydroelectric dam in the world. Completed in 2012, it generates more power than any power station in the world, producing 98.8 terawatt hours of power. It is capable of generating 22,500 megawatts of power using 32 turbines. Over 1,300,000 people were displaced as result of living in the valleys above the site of the dam. This fact, along with the potential loss of thousands of archaeological sites, has been a source of controversy since the project was conceived in the 1990s.
What is the difference between climate and weather?
Climate is the long-term (usually 30-year) average weather for a particular place. The weather is the current condition of the atmosphere. So, on a particular day, the weather in Barrow, Alaska, might be a hot 70° Fahrenheit, but its tundra climate is generally polar-like and cold.
How are different types of climates classified?
In 1884, the German climatologist Wladimir Köppen developed a climate classification system that is still used today, albeit with some modifications. He classified climates into five categories: tropical/megathermal, dry, temperate/mesothermal, continental/microthermal, polar, and alpine. He also created subcategories for these classifications. His climate map is often found in geography texts and atlases. In the 1960s, the climate classifications were updated to take into account vegetation that is native to certain climatic zones, providing more accuracy to the classification system.
What is a Mediterranean climate?
A Mediterranean climate is a climate similar to the one found along the Mediterranean Sea: warm, hot, and dry in the summer and mild, cool, and wet in the winter. Areas that are renowned for having a Mediterranean climate but are not near the Mediterranean Sea are California, southwestern Oregon, southwestern South Africa, and Chile.
What is global warming?
Global warming is the gradual increase of the Earth’s average temperature—which has been rising since the Industrial Revolution (late eighteenth century–early nineteenth century C.E.). If temperatures continue to increase, some scientists predict major climatic changes, including the rise of ocean levels due to ice melting at the poles. According to many scientists, global warming is primarily due to the greenhouse effect.
How did the Inca civilization experiment with climate?
In the Urubamba Valley in Peru, in a city called Moray, are the remains of a great amphitheater-like terraced system. Archaeologists and scientists now believe that this was a great agricultural laboratory, where each area of the terrace exhibited completely different climates, allowing the Incas to experiment on cultivated vegetation with different climates and growing techniques.
What is the greenhouse effect?
The greenhouse effect is a natural process of the atmosphere that traps some of the sun’s heat near the Earth. The problem with the greenhouse effect, however, is that it has been unnaturally increased, causing more heat to be trapped and the temperature on the planet to rise. The gasses that have caused the greenhouse effect were added to the atmosphere as a byproduct of human activities, especially combustion from automobiles, output from factories, and the burning of forests.
What is the effect of global warming and climate change on Earth?
By the year 2100, relative to 1990, world temperatures could rise from 2 to 11.5° Fahrenheit (1.1 to 6.4° Celsius), and sea levels may rise 7.2 to 23.6 inches (18 to 59 centimeters). According to scientists at NASA, for 650,000 years, atmospheric carbon dioxide, a main contributor to warming, has never been above 300 parts per million. Since 1950, this number has steadily increased to nearly 400 parts per million in 2014.
What is air pollution?
Air pollution is caused by many sources. There are natural pollutants that have been around as long as the Earth, such as dust, smoke, volcanic ash, and pollens. Humans have added to air pollution with chemicals and particulates due to combustion and industrial activity.
What are the most polluted cities in the world in terms of air quality?
Scientists measure pollutants that are present in the air that we breathe by measuring the size of the particulate, including cancer-causing ammonia, carbon, nitrates, and sulfate. These pollutants easily pass into our bloodstream when we breathe. The places in the world where we may find severe concentrations of these chemicals in the air include New Delhi, India; Patna, India; Gwalior, India; Raipur, India; and Karachi, Pakistan. Of the top twenty most polluted cities in the world, according to the World Bank, thirteen are in India. The rest include Doha, Qatar; Igdir, Turkey; and Khorramabad, Iran.
What are the sources of air pollution?
Air pollution has two main sources: anthropogenic (man-made) and natural. Man-made sources of pollution include factories, cars, motorcycles, ships, incinerators, wood burning, oil refining, chemicals, consumer product emissions like aerosol sprays and fumes from paint, methane from garbage in landfills, and pollution from nuclear and biological weapons production and testing. Natural sources of pollution may include dust, methane from human and animal waste, radon gas, smoke from wildfires, and volcanic activity.
How much pressure does the atmosphere exert upon us?
Average air pressure is 14.7 pounds per square inch (1.0335 kilograms per square centimeter) at sea level.
Why is the sky blue?
This is one of the world’s most frequently pondered questions, and, contrary to what some people believe, the sky’s blue color is not due to the reflection of water. Light from the sun is composed of the spectrum of colors. When sunlight strikes the Earth’s atmosphere, ultraviolet and blue waves of light are the most easily scattered by particles in the atmosphere. So, other colors of light continue to the Earth while blue and ultraviolet waves remain in the sky. Our eyes can’t see ultraviolet light, so the sky appears the only color remaining that we can see: blue.
How many layers are in the atmosphere?
There are five layers that make up the Earth’s atmosphere. They extend from just above the surface of the Earth to outer space. The layer of the atmosphere that we breathe and exist in is called the troposphere and extends from the ground to about 10 miles (16 km) above the surface. From about 10 miles to 30 miles (16 to 48 km) up lies the stratosphere. The mesosphere lies from 30 to 50 miles (48 to 80 km) above the surface. A very thick layer, the thermosphere, lies from 50 miles all the way to 125 miles up (80 to 200 km). Above the 125-mile (200-km) mark lies the exosphere and space.
Earth’s atmosphere is much thicker than most people think. Many just consider it the part that is the troposphere, but it actually extends about 6,200 miles (10,000 kilometers) into space.