Currently being rolled out the the US but will be going worldwide soon. There is a phased roll-out and it sounds like specific sectors are going to target first, but ultimately anyone who is promoting google, products or services, promoting information or working in regular industries such as gambling is going to have to prove their identity proven.
This is for all of Google ads products, search, display and YouTube. There will be a message and you will have 30 days to comply. Make sure that you know who has your account admin email and make sure they are looking out for this important notification as if you fail to comply your ads could be switched off.