In today's top stories, Google will no longer mandate COVID-19 vaccines as a condition of employment for US workers and won't require already vaccinated workers to wear masks, get tested or socially distance while working in most offices. In other news, the surface of the Greenland ice sheet is melting, creating a network of ephemeral rivers and waterfalls that scientists say produces more hydropower than the collective output of the 10 largest hydroelectric stations on the planet.