Megafires, individual fires that burn more than 100,000 acres, are on the rise in the western United States -- the direct result of unintentional yet massive changes we've brought to the forests through a century of misguided management. What steps can we take to avoid further destruction? Forest ecologist Paul Hessburg confronts some tough truths about wildfires and details how we can help restore the natural balance of the landscape.

Congratulations! By being here, alive, you are one of history's winners -- the culmination of a success story four billion years in the making. The other 99 percent of species who have ever lived on earth are dead -- killed by fire, flood, asteroids, ice, heat and the cold math of natural selection. How did we get so lucky, and will we continue to win? In this short, funny talk, paleobiologist and TED Fellow Lauren Sallan shares insights on how your ancestors' survival through mass extinction made you who you are today.

Could we cure climate change? Geoengineering researcher Tim Kruger wants to try. He shares one promising possibility: using natural gas to generate electricity in a way that takes carbon dioxide out of the air. Learn more -- both the potential and the risks -- about this controversial field that seeks creative, deliberate and large-scale intervention to stop the already catastrophic consequences of our warming planet.

The Greenland ice sheet is massive, mysterious -- and melting. Using advanced technology, scientists are revealing its secrets for the first time, and what they've found is amazing: hidden under the ice sheet is a vast aquifer that holds a Lake Tahoe-sized volume of water from the summer melt. Does this water stay there, or does it find its way out to the ocean and contribute to global sea level rise? Join glaciologist Kristin Poinar for a trip to this frozen, forgotten land to find out.

Sara Menker quit a career in commodities trading to figure out how the global value chain of agriculture works. Her discoveries have led to some startling predictions: "We could have a tipping point in global food and agriculture if surging demand surpasses the agricultural system's structural capacity to produce food," she says. "People could starve and governments may fall." Menker's models predict that this scenario could happen in a decade -- that the world could be short 214 trillion calories per year by 2027. She offers a vision of this impossible world as well as some steps we can take today to avoid it.

Photographer Levon Biss was looking for a new, extraordinary subject when one afternoon he and his young son popped a ground beetle under a microscope and discovered the wondrous world of insects. Applying his knowledge of photography to subjects just five millimeters long, Biss created a process for shooting insects in unbelievable microscopic detail. He shares the resulting portraits -- each comprised of 8- to 10,000 individual shots -- and a story about how inspiration can come from the most unlikely places.

More than 100 years after Albert Einstein predicted gravitational waves -- ripples in space-time caused by violent cosmic collisions -- LIGO scientists confirmed their existence using large, extremely precise detectors in Louisiana and Washington. Astrophysicist Gabriela González of the LIGO Scientific Collaboration tells us how this incredible, Nobel-winning discovery happened -- and what it might mean for our understanding of the universe. (In Spanish with English subtitles)

When you think about the deep blue sea, you might instantly think of whales or coral reefs. But spare a thought for giant clams, the world's largest living shellfish. These incredible creatures can live to 100, grow up to four and a half feet long and weigh as much as three baby elephants. In this charming talk, marine biologist Mei Lin Neo shares why she's obsessively trying to turn these legendary sea creatures into heroes of the oceans.

How can you study Mars without a spaceship? Head to the most Martian place on Earth -- the Atacama Desert in Chile. Astrobiologist Armando Azua-Bustos grew up in this vast, arid landscape and now studies the rare life forms that have adapted to survive there, some in areas with no reported rainfall for the past 400 years. Explore the possibility of finding life elsewhere in the universe without leaving the planet with this quick, funny talk.

What the astronauts felt when they saw Earth from space changed them forever. Author and artist Benjamin Grant aims to provoke this same feeling of overwhelming scale and beauty in each of us through a series of stunning satellite images that show the effects human beings are having on the planet. "If we can adopt a more expansive perspective, embrace the truth of what is going on and contemplate the long-term health of our planet, we will create a better, safer and smarter future for our one and only home," Grant says.