According to EarthDay.org, Earth Day was founded in 1970 by U.S. Senator Gaylord Nelson, who called for a “national teach-in on the environment” after witnessing the terrible effects of the 1969 oil spill in Santa Barbara, California. The first Earth Day brought major actions to the streets of many major U.S. Cities. For fun, check out this vintage newscast from after that first Earth Day.

Earth Day went global in 1990 and, today, is celebrated in an estimated 192 countries. Which makes today the perfect day to take time to appreciate the land, air, oceans and wildlife that sustain us — and to think about how our lives, both individually and as a group, affect the environment. To that end, here are 12 talks — some reflective, some terrifying, some beautiful, some galvanizing — to watch today.

Al Gore: New thinking on the climate crisis Al Gore: New thinking on the climate crisis Former vice president Al Gore flipped the way so many think about global warming in the documentary An Inconvenient Truth. Two years after the doc’s release, he returned to the TED stage with a new presentation … showing that the impact of climate change may be even worse than scientists had predicted.

Louie Schwartzberg: Nature. Beauty. Gratitude. Louie Schwartzberg: Nature. Beauty. Gratitude. Louie Schwartzberg is a master of time-lapse photography, and his images of flowers dancing as they bloom will pierce your heart. In this talk from TEDxSF, he invites Benedictine monk David Steindl-Rast to lead a meditation on gratefulness for the beauty and bounty that surrounds us.

Sylvia Earle's TED Prize wish to protect our oceans Sylvia Earle’s TED Prize wish to protect our oceans Ocean researcher Sylvia Earle knows that the waters of the deep contain amazing wonder. And yet, she worries that they are quickly becoming a “paradise lost.” Watch Earle accept the TED Prize at TED2009 and unveil Mission Blue, an initiative to protect our oceans. As she puts it, “No blue, no green. If you think the ocean isn’t important, imagine Earth without it. Mars comes to mind.”

John Doerr sees salvation and profit in greentech John Doerr sees salvation and profit in greentech Silicon Valley legend John Doerr had an ‘aha’ moment when his 15 year old daughter accused him and his generation of ruining the planet. In this talk from TED2007, he gives a personal, heartfelt call for investors to look at clean energy, and for big companies to make the little changes that will add up over time.

Vicki Arroyo: Let's prepare for our new climate Vicki Arroyo: Let’s prepare for our new climate As our climate changes, many areas of the world — including major cities like New Orleans — are at risk of flooding and drought. In this talk from TEDGlobal 2012, Vivki Arroyo calls on use to prepare now, by sharing examples of cities that are planning ahead and implementing big projects that take these risks as a given.

Karen Bass: Unseen footage, untamed nature Karen Bass: Unseen footage, untamed nature Karen Bass shoots incredible wildlife footage for National Geographic and the BBC. In this talk from TED2012, she shares awe-inducing video — from the tube-lipped nectar bat feeding on a flower to grizzly bears emerging from hibernation.

James Hansen: Why I must speak out about climate change James Hansen: Why I must speak out about climate change Scientist James Hansen saw it as his moral imperative to speak out about the rapidly changing planet he saw in his work. In this talk from TED2012, Hansen explains why global warming is happening (“Adding CO2 to the air is like throwing another blanket on the bed”) and calls on us to start reversing it.

Capt. Charles Moore on the seas of plastic Capt. Charles Moore on the seas of plastic We recycle a “diddly-point-squat” percentage of the plastics we use. The result — they end up in the oceans.  In this talk from TED2009, Captain Charles Moore shows us the Great Pacific Garbage Patch — an endless floating wasteland of plastic. His call to all of us: to stop our throwaway mentality and stop the plastic on land.

David Keith's unusual climate change idea David Keith’s unusual climate change idea Environmental scientist David Keith bemoans the fact that we’ve been reading the same headlines about the environment since the 1950s, while achieving very little to change them. In this talk from TEDSalon 2007 Hot Science, he shares a bold idea: What if we released a huge cloud of ash into the atmosphere to deflect sunlight and heat?

Cesar Harada: A novel idea for cleaning up oil spills Cesar Harada: A novel idea for cleaning up oil spills When TED Senior Fellow Cesar Harada heard about the BP Oil Spill in the Gulf of Mexico, he quit his job and set about designing an efficient way to soak up oil. At the TEDxSummit, he shares his creation — a highly-manueverable boat that is capable of cleaning large tracts of oil quickly.

Alex Steffen: The route to a sustainable future Alex Steffen: The route to a sustainable future If people across the globe had the ecological footprint of those in the United States, we’d need 5 to 7 planets to sustain it all, says Alex Steffen at TEDGlobal 2005. But of course, we only get one. Here, he asks us to actively reduce our footprint, especially as the consumer lifestyle spreads across the globe.

James Balog: Time-lapse proof of extreme ice loss James Balog: Time-lapse proof of extreme ice loss Thanks to photographer James Balog’s Extreme Ice Survey, we can actually see glaciers recede before our eyes — the process of several years condensed into a few seconds.  In this talk from TEDGlobal 2009, Balog shares how he brings together art and science to deepen all our understanding of how quickly ice is disappearing. (See also: Camille Seaman’s haunting photos of polar ice.)