#9/15 What is the environment?
How does planet Earth work?
The atmosphere, mountains, oceans and all non-biological life make up the physical environment. This forms the scaffolding for ecosystems.
Imagine the globe like a mixing bowl where ingredients settle in the bottom. Fossil carbon from plants was deposited in valleys 200 million years ago when dinosaurs roamed the Earth. Deep soil eventually buried this high-energy material safely underground. In the Atlantic, there are sediment layers a kilometre thick, that settled over millions of years.
But our planet is also a rotating sphere, surrounded by fluid and that’s important for our weather. When gravity presses down on the oceans, it creates friction with the seabed, so the surface flows faster than the deep. This creates a series of interlocking, spinning wheels of water around the equator. This is how ocean currents and hurricanes form.
As Earth orbits the Sun, it warms different areas of our planet and the distribution of heat changes. So does the pattern of warming and cooling throughout the continents and oceans. For example, in the northern hemisphere’s summer, India warms and wet air from the ocean rises over the 7,500 m high Himalayas, creating rain and snow. The same winds suck air from the southeast, stirring the Banda Sea in Indonesia where cold water comes up from 7,500 m deep, to cool the Earth and dry Australia.
There are similar processes like El Nino in the Pacific and the Atlantic Mid Ocean Current where heat ebbs and flows like a tide, seasonally or every few years.
Up until quite recently, these patterns were relatively stable. Animals depend on this stability as it delivers predictable rainfall and lets us find and grow food. Water is an essential ingredient for life in the biosphere.
