What exactly is the carbon cycle? Nathaniel Manning provides a basic look into the cyclical relationship of carbon, humans and the environment.

There's a game of Tetris happening on a global scale: The playing space is planet Earth, and all those pesky, stacking blocks represent carbon dioxide -- a greenhouse gas that is piling up ever more rapidly as we burn the fossil fuels that run our cars, factories and power plants. Joss Fong outlines how this overload of CO2 leads to climate change and reminds us that, unlike Tetris, we won't get an opportunity to start over and try again.

In 4 minutes, atmospheric chemist Rachel Pike provides a glimpse of the massive scientific effort behind the bold headlines on climate change, with her team -- one of thousands who contributed -- taking a risky flight over the rainforest in pursuit of data on a key molecule.

In this intimate talk filmed at TED's offices, energy innovator Amory Lovins shows how to get the US off oil and coal by 2050, $5 trillion cheaper, with no Act of Congress, led by business for profit. The key is integrating all four energy-using sectors—and four kinds of innovation.

Energy is neither created nor destroyed — and yet the global demand for it continues to increase. But where does energy come from, and where does it go? Joshua M. Sneideman examines the many ways in which energy cycles through our planet, from the sun to our food chain to electricity and beyond.

Photographer James Balog shares new image sequences from the Extreme Ice Survey, a network of time-lapse cameras recording glaciers receding at an alarming rate, some of the most vivid evidence yet of climate change.