Brightening clouds. Refreezing the Arctic. Floating a giant parasol in outer space. To the ranks of out-there ideas for countering climate change, two Dutch scientists have added this: building a 50-mile-long dam across the Bering Strait, the shallow waterway that separates Russia and Alaska. In a study published Friday in the journal Science Advances, the researchers show that, under certain conditions, such a dam could prevent a collapse of a network of ocean currents, known as the AMOC, that plays a central role in regulating Earth’s climate. The AMOC (pronounced AY-mock) has weakened in recent decades, and a growing body of evidence suggests human-caused warming could someday cause it to shut down or slow significantly, with grave effects on the weather on multiple continents. The new study is a “proof of concept,” not an action plan, said one of its authors, Jelle Soons, a doctoral candidate at Utrecht University in the Netherlands.…