The ice caps are the planet's heat sink. When they fall apart, all kinds of feedbacks kick in and the climate goes to hell in short order. Here's a graph that shows planetary ice extent. Notice anything frightening about 2016?
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More troublesome yet, there are gigatons worth of methane clathrates ready to melt and contribute more greenhouse gasses than the planet has seen in millions of years.
I'm not advocating action. We're past all that now.
You're 1st job, before crapping your pants, is to resolve the Japanese Sea Ice tracking with this "GLOBAL" sea ice graph of yours.
According to THIS the 2016 Dec sea ice was less than 0.8 mill km2 less than the 1980s average.
The other detail, which I checked just weeks ago on the NSIDC site is that the DEFICIT in 2017 (late 2016) in the Arctic was largely due to just ONE or TWO warmer days during the "onset of the ice growing season". That's why "ice" is not a thermometer or a metric that follows climate in the SHORT term.
You could LOSE all the Arctic Sea Ice, not raise the ocean levels and REBUILD it ALL in less than a couple decades. Since hardly any of it is "OLD ice"...
On the other side of the globe -- you had RECORD HIGH sea ice in Antarctica just a couple years ago. The panic here is that the tools are better and folks are seeing weather variations that were not AVAILABLE just 30 years ago BEFORE the satellite era.
Now --- there is NO DOUBT that Arctic sea ice is in long term decline. Has been since the Little Ice Age in the 1700s. But panicking about daily, monthly, yearly charts is not science.
Finally, there is not enough calthrates to melt due to surface exposures. Russians have said that the major reserves in the Siberia are most prone to earthquakes than from a few degrees of surface warming. And the harder question is -- if those feedbacks are so destructive and powerful -- how come ALL the calthrates did not melt during the rapid spikes of the last FOUR interglacial warming periods? Four TIMES -- most of the ice cover retreated putting MASSIVE amounts of CO2 CH4 back in circulation. Why did that STOP -- if CO2 drives the planet to commit suicide with just a 2degC forcing now? FOUR chances for the Earth "to run away" and destroy itself with "overloading" GH gases --- and it did not.