Watch these recommended TED-Ed Lessons:

How long will human impacts last?
Imagine aliens land on Earth a million years from now. What will these curious searchers find of us? They will find what geologists, scientists, and other experts are increasingly calling the Anthropocene, or new age of mankind. David Biello explains how the impacts that humans have made have become so pervasive, profound, and permanent that some geologists believe we merit our own epoch.

Why the Arctic is climate change’s canary in the coal mine
The Arctic may seem like a frozen and desolate environment where nothing ever changes. But the climate of this unique and remote region can be both an early indicator of the climate of the rest of the Earth and a driver for weather patterns across the globe. William Chapman explains why scientists often describe the Arctic as the “canary in the coal mine” when it comes to climate change.

Are we running out of clean water?
Despite water covering 71% of the planet’s surface, more than half the world’s population endures extreme water scarcity for at least one month a year. Current estimates predict that by 2040, up to 20 more countries could be experiencing water shortages. These statistics raise a startling question: is the Earth running out of clean water? Balsher Singh Sidhu takes a closer look at water consumption.

When will the next mass extinction occur?
About 66 million years ago, a terrible extinction event wiped out the dinosaurs. But it wasn’t the only event of this kind -- extinctions of various severity have occurred throughout the Earth’s history -- and are still happening all around us today. Borths, D'Emic, and Pritchard give a quick history of mass extinctions.

What really happens to the plastic you throw away
We’ve all been told that we should recycle plastic bottles and containers. But what actually happens to the plastic if we just throw it away? Emma Bryce traces the life cycles of three different plastic bottles, shedding light on the dangers these disposables present to our world.

The life cycle of a t-shirt
Consider the classic white t-shirt. Annually, we sell and buy 2 billion t-shirts globally, making it one of the most common garments in the world. But how and where is the average t-shirt made, and what’s its environmental impact? Angel Chang traces the life cycle of a t-shirt.