Since the very first Earth Day on April 22, 1970, over 20 million Americans from all walks of life have contributed to major environmental accomplishments. For 2012, the Earth Day Network is again hosting “A Billion Acts of Green®” with the ambitious goal of registering another one billion environmentally friendly actions.

In honour of Earth Day – scheduled this year for Sunday April 22 – and our focus this month on ecotourism, we’re thinking about our planet. We’re thinking about the human activities that have the most harmful impact on it, especially the one we love most – travel. We’re compelled to ask: What is tourism in its worst form, environmentally? Even in its best form, can the cost to the earth of tourism ever really be offset?

Regular viewers of our Video Spotlight feature will already know that we’re big fans of David Attenborough. This week, it’s our pleasure to bring you something ever so slightly different. Think of it as an early Christmas present to those of you that celebrate it and if you don’t, this is still something that absolutely everyone can (and should) enjoy.

This genuinely amazing video, compiled by filmmaker Michael König using images shot from recent missions on the International Space Station (ISS), reminds us that space, as a wise man once said, is the final frontier. But with our ambition and pioneering instinct, mankind has never been particularly daunted by frontiers. If we’re ever to get anywhere, though, we should never forget where we come from.

No fewer than 1.6 billion people — nearly a quarter of the world’s population — depend on forests for their livelihoods. Forests are also critical to maintaining biodiversity, mitigating climate change and enabling key ecosystem functions that regulate the biosphere. And yet about 45 per cent of the world’s forests have already been cleared. Here are some hard numbers to ponder that tell us how and why we should stop.

The One Day on Earth project began in 2008, with the vision of uniting the entire world in a single film-related project. The potential for collaboration offered by the internet is something that continues to be explored to this day, but the group behind One Day on Earth set out to achieve something that had never been seen before: a collection of moments, experiences and events from all corners of the globe with a single unifying experience – they all took place on the same day.