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For a century and a half, melting snow and ice have been the most recognizable visual evidence of climate change. You can see it in the Arctic Ocean, where the first ice-free summer in two and a half million years is predicted by 2035; in the Alps, where half of the range’s iconic glacial ice has vanished; and in the Rockies, Great Lakes and even Northeastern backyards—which were once layered with snow all winter long but now show bare earth throughout the dark months.
Even now, at this late stage in the warming crisis, the unambiguous message that the Great Melt is sending is being obscured. The resulting delay in human action has delivered a new threat: if decisive action is not taken immediately, this harbinger of climate change will morph into the first colossal domino in a cascade of natural disasters—all of which will alter life and civilization as we know it.
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If the end of our world is to come, it will likely come by way of nine natural tipping points. Climatologists say that each, if crossed, would likely result in unstoppable, runaway climate change—taking the future of the planet out of human hands. Five of these thresholds depend on the cryosphere, or frozen regions where water exists as a solid: 1) boreal forest dieback, fueled by historically low spring snowpack; 2) rising sea levels, two thirds of which derives from melting and calving ice; 3) nine million square miles of methane-rich Arctic permafrost, that, if thawed, could release more greenhouse gases than humans ever did; 4) the melting Antarctic and Greenland ice sheets that could raise sea levels more than 200 feet; and 5) meltwater from those sheets that could slow or shut down major ocean currents like the Gulf Stream, sending northern Europe into an ice age and transforming parts of the Middle East and Asia into a desert.
To envision just how much ice the planet has lost, and how it is indelibly altering our planet, consider this: melt on the poles in just…
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Source : time
