The phrase “melting of the polar ice cap” refers to what’s happening in the Arctic. “melting of the polar ice caps” would cover both ends. I was indicating that the use of “unequivocally” is pretty much ridiculous. The most likely main cause, clearly, but the linkage is not unequivocal and never will be.
Still nonsense, but getting warmer (so to speak.)
The most likely cause of variations in the size of our polar caps from year to year is the cyclical nature of our planetary weather patterns, that have been occurring for billions of years.