merbs writes The scientists had whipped themselves into a frenzy. Gathered in a stuffy conference room in the bowels of a hotel in Berlin, scores of respected climate researchers were arguing about a one-page document that had tentatively been christened the "Berlin Declaration." It proposed ground rules for conducting experiments to explore how we might artificially cool the Earth—planet hacking, basically. This is the story of scientists' first major international meeting to tackle geoengineering. It’s most commonly called geoengineering. Think Bond-villain-caliber schemes but with better intentions. It’s a highly controversial field that studies ideas like launching high-flying jets to dust the skies with sulfur in order to block out a small fraction of the solar rays entering the atmosphere, or sending a fleet of drones across the ocean to spray seawater into clouds to make them brighter and thus reflect more sunlight. Those are two of the most discussed proposals for using technology to chill the planet and combat climate change, and each would ostensibly cost a few billion dollars a year—peanuts in the scheme of the global economy. We’re about to see the dawn of the first real-world experiments designed to test ideas like these, but first, the scientists wanted to agree on a code of ethics—how to move forward without alarming the public or breaking any laws.