The Board of the Bulletin of the Atomic Scientists and Security have advanced the hands of the "Doomsday Clock" to "3 Minutes To Midnight". This is in response to "... unchecked climate change and a nuclear arms race resulting from modernization of huge arsenals pose extraordinary and undeniable threats to the continued existence of humanity". From: "It Is 3 Minutes To Midnight - Climate Change And Nuclear Tensions Push Doomsday Clock Hands Forward", Media Release, 22 January 2015. There is also a more detailed Analysis: Three minutes and counting.
Perhaps there should be a standardized global "Hot Line" for use between nations. The hard part would be agreeing who could talk to who and having them train to use the system. Not much hardware or software is needed: the Moscow–Washington hot-line uses off-the-shelf text-chat and email software (such hot-lines don't use voice communication). However, such a system would have to operate in the face of cyber-attacks and electronic warfare, by the nations involved in the dispute and third parties.