The phrase “Methane Bomb” or sometimes “Arctic Methane Bomb” refers to a huge risk for an event that we can't accurately forecast. It has the opportunity to rip control away from humans and finish heating the planet past supporting life as we know it. As the video clip below puts it; If nature starts putting out global warming gasses as fast as humans are, now, then it will no longer save the situation for humans to stop putting their share out. It is a real risk, and should bring an urgency to attempts to stop CO2 emissions that has not been in anyone's serious planning, yet.
The issue is that a huge amount of methane has been stored in the arctic over millions of years. This was necessary to switch life on earth from anaerobic life (organisms for which oxygen is a poison) to aerobic life (organisms like us that breath oxygen). Almost all current animal life forms are aerobic, and they depend on the oxygen-tolerant plants on land and in the ocean to resupply the oxygen that we breath.
A good article appears here:
“How Much Should You Worry About an Arctic Methane Bomb?”
““Recent warnings that this greenhouse gas could cost us $60 trillion have received widespread publicity. But many scientists are skeptical.””
The following video addresses this issue, but is quite long because of background material and following motivational material.
Expand the outline here (click on 2 arrows), and see if it lets you comfortably look at the video clip, below it. This issue is one of many examples of climate tipping points.
So, the following excerpt from the above movie covers the possibility of released methane-hydrates from the arctic ocean producing a catastrophic worsening of global warming at some undetermined time in the upcoming decades. (A bit like asking when the “Big One” (9.0 Earthquake and Tsunami) is coming).