Arid Climates

Arid climates

An arid climate is one that receives less than 10 inches (25.4 centimeters) of rainfall in an entire year. Deserts are areas that are arid. Although the most familiar image of a desert involves hot sand, the Arctic North and Antarctica are also deserts, as they also receive little moisture, usually in the form of snow.

In contrast, the island of Fiji receives drenching rains for several months of the year, and is located in a tropical area of the world. Fiji receives an astounding 120 inches of rain each year, more than ten times the rainfall that falls in arid areas.

The rain that falls in an arid climate is sporadic and when it does fall, it is usually in the form of a thunderstorm. Flash floods are frequently a danger in arid climates after thunderstorms as the dry, compact soil cannot absorb water quickly enough to capture the rain. Streams swell with water for a few hours and then dry up again until the next cloudburst.

Exploration of the Oceans

Exploration of the Oceans

For centuries, exploration of the oceans was primarily limited to exploration on the surface of the oceans. Explorers sailed or rowed ships across the seas in search of new lands or natural resources.

Biological limits prevented humans from exploring beneath the surface. Three main issues prevented humans from exploring great depths of the ocean. First, humans must breathe air to survive, and humans can hold their breath for several minutes or less.

This does not provide much time to dive, explore, and return to the water’s surface. Second, the weight of water increases greatly as a diver descends into deep water. Finally, water temperature decreases with increasing depths. The temperature near the ocean floor is near freezing.

Water and Cultures in the Ancient World

Ancient Egyptian Temple, Island of Philae, Nile River, Egypt

Water was the center of life in many ancient cultures. In Greek mythology, one of the most ancient and powerful gods was Neptune, the god of the sea. Ancient Greek literature, such as The Odyssey by Homer (about 800 b.c.e.), mentions sea monsters, whirlpools, and harrowing voyages upon the sea. In India, the Ganges River was considered sacred from historical accounts over 3000 years old.

To the ancient Egyptian, the Nile River was the political, economic, and life-sustaining center of their kingdom. Without the Nile, Egypt would be as barren as its nearby deserts. Ancient civilizations’ respect for water grew from their absolute need for water. Like today, water sustained life in many ways.

Seafaring in the ancient world

Ancient cities constructed beside the sea based their economies on the nearby water. Fishing, exploration, trade, and warfare necessitated shipbuilding. Shipbuilding was one of the most important crafts of the ancient world.

Water and Cultures in the Modern World

Sidney opera house

Water plays an important role in shaping the modern world. Cities are built on water. Humans rely on water for cooking, drinking, washing, transportation, trade, energy, irrigation (watering crops), and recreation.

The use of water in the modern world has also created problems. Population growth and advancements in technology threaten the world’s water supply. Overfishing and pollution stress many of the world’s seas, and shortages of water stress human populations in arid (extremely dry) lands.

Cities and ports

Most cities are located beside water, Coastal areas in particular boast large cities. Eight out of the top ten most populous cities in the world lie on the coast. Nearly 44% of the world’s population lives within 100 miles (161 kilometers) of a coast.