Global (and InterPlanetary) PubSub routing?

Hi, new here, considering whether there’s potential for a global PubSub network for environmental data, weather alerts, and so on. (If I’m not the first one to propose something like that, pointers will be much appreciated!)

Would a set of open-data global topics need to be supported by some sort of global bootstrapper to ensure that everyone who wanted to got into the same p2p universe? And if so, does one exist? Or is there some other way to approach making a topic universally reachable?

Thanks!

Art
Networks and Services for Public Safety and Emergency Management
art@botterell.net