As Arctic sea ice dwindles, Greenland could become the center of coldness in the Arctic. Because Greenland is far south of the pole, this could increase the destabilization of weather in the Northern hemisphere, causing even bigger and longer rains which will often ruin harvests.

This trend has already been observed in recent years. The point is that the Greenland effect could make it get much worse, and quickly, in a few decades.

It's not a certainty. Want to bet your life that it won't happen?