Supposedly, Herodotus wrote that when the Greeks were told that the Persian archers at the Battle of Thermopylae would blot out the sun with their arrows, they responded: “Good, then we shall have our battle in the shade.”

Fast forward to the early 21st century and the issue is no longer Persian arrows, but the relentless heat from a sun less and less buffered by earth’s atmosphere because of the accumulated greenhouse gasses. The result, according to scientists, is a rapidly warming planet with increasingly extreme weather, droughts and floods, supercyclones and hurricanes, raging forest fires, or other unusually intense natural disasters. All of that has become the new normal with every likelihood that what’s extreme today might be perceived as moderate next year. The need for shade has never been greater!

What can be done?

One possibility is what’s called "solar radiation management.” SRM essentially amounts to reducing the amount of solar radiation hitting, and hence warming, the planet. It's either an obvious approach—think, if not Persian arrows then the eruption of huge volcanoes—or crazy dangerous, depending on where you sit.

Luke Iseman and Andrew Song think it’s obvious, and are pioneers in trying to deflect solar radiation away from the Earth. But, unlike scientists, they have decided to stop talking about it and have begun doing it. Listen as they explain how they think they can cool the planet.

Is it okay for individuals to try to re-engineer the climate? Tell us what you think.