Lots of people are concerned about methane hydrates in Arctic ocean sediments, that they could release enough methane, a powerful greenhouse gas, to derail Earth’s climate. I will show recent modeling work, finding a thermodynamic exclusion of methane hydrate from the permafrost zone, confining the hydrate to depths of hundreds of meters below the sea floor, precluding a fast response to changes in temperature. So Arctic methane seems negligible in the global methane budget. Forget Arctic methane.

Speaking of methane, it differs from CO2 in that methane degrades in the atmosphere in about a decade, while CO2 essentially accumulates in the atmosphere / ocean system. To deal with global warming, we have defined a goal of minimizing the peak global temperature change. The negotiating target is 2 degrees C, which would come in aboutyear 2050. Methane we release now will be long gone by 2050; it will have oxidized to CO2. The rate of methane emission is much lower than that of CO2, so methane only really matters if we count the methane as much more powerful than CO2, which, for now, defined in this way, it isn’t. So forget methane altogether.

In observance of the fact that the CO2 system is what we need to pay attention to, I’ll present a new perspective, that we were actually very lucky. If the natural CO2 concentration had been much lower than it turned out to be, the climate impacts would have come sooner in time, making it much more difficult for humanity to figure out what is going on in time to do something about it.