PBS's Nova documentary series recently re-aired an episode from 2013, that is so good I watched it again, and I'm compelled to write about it here. It's a special episode called "Earth From Space" is viewable online at this link, for free, and I strongly encourage taking the time to watch it.
Here are some highlights if you can't watch the whole thing.
0 hours 36 minutes -- Antartica and the surrounding ice shelf is a key driver of the global climate. The ice that forms around the continent squeezes out salt (brine), which is denser than the surrounding water, and that cascades down through ocean caverns and along the global sea floor. This brine flow (also known as the haline cycle) drives the flow of water and nutrients ultimately around the planet, in a massive global conveyer belt called the thermohaline circulation cycle.
1h 03m -- African Saharan diatomite dust (the remains of ancient plankton) is carried by equatorial winds to the Amazonian rain forest, where it is rained out of the atmospheric, providing much needed phospates to fertilize the basin.
1h 14m -- Oxygen in the atmosphere is obviously critical to advanced life forms including mamals like us. Satellite data shows that Earth has a daily "breathing" cycle, where plants receive sunlight during the day and produce oxygen, but also indicates that huge rainforests like the Amazon actually keep most of that oxygen (via reabsorbing at night). Satellite data is showing that the rainforest runoff produces massive plankton blooms, and they consume carbon dioxide and produce oxygen that then finds its way into the atmosphere and is available to the entire planet.
1h 40m -- The Sun's magnetic field and interaction with Earth's magnetic field, illustrated with fantastic animations (produced by supercomputers) that show the Earth being buffeted by the Sun's activity. Without our magnetic field, Earth's atmosphere would slowly get stripped away and the Sun would scorch the Earth. By the way, we now believe that this is what happened to Mars; it once had a magnetic field, which allowed it to have a thicker atmosphere and liquid water on the surface (implying life), but the magnetic field disappeared and the planet was transformed into the frigid, dry wasteland that our probes are exploring today.
1h 47m -- Finally, satellite data is revealing how much human activity is now dwarfing Earth's natural cycles. Our growing presence is now starting to interrupt natural processes that have evolved over billions of years. Nitrates from lightning, sulfur from volcanoes, dust from the deserts --all of these sources are now already completely overtaken and dwarfed by human industrial activity.
The difference between the natural processes and our own is that we make conscious decisions about what we do.