THE CRA PERSPECTIVE • EARTH SCIENCE How Much Water Is There on Earth? Can our planet ever run out of water? Exploring Earth's enormous water reserves, the freshwater shortage and the future of humanity. Water is one of the most extraordinary and essential resources on our planet. Our planet is called the Blue Planet for a reason. Approximately 71% of Earth's surface is covered by water. But does that mean we have an unlimited supply of water for human survival? Look at the oceans, rivers, lakes, glaciers and countless streams across the world. Water seems almost endless. It falls as rain, flows through rivers, disappears into the ground, freezes into ice and rises into the atmosphere as water vapour. Yet billions of people experience water shortages. Some communities struggle to obtain safe drinking water, groundwater reserves are declining in several regions, and pollution is making important water sour...
The idea of harnessing the sun’s energy may seem like a modern invention, but humanity has been relying on solar power for thousands of years. From ancient civilizations that used sunlight for daily needs to today’s cutting-edge solar panels, the journey of solar power reflects our enduring relationship with the greatest energy source of all—the Sun. 🏺 Ancient Origins of Solar Power Long before technology, people understood the sun’s potential: Greek and Roman Civilizations: They designed homes and bathhouses with large south-facing windows to capture and trap sunlight for warmth—a technique known as passive solar heating . Chinese Architecture: Ancient Chinese builders positioned houses to maximize sunlight in winter and shade in summer, practicing early energy efficiency. Magnifying Glass Experiments: As early as 7th century BCE, people used magnifying glasses to focus sunlight and create fire. Solar Worship: Beyond practicality, many cultures, including ...