Let us say that for some unexplained reason the Earth’s core began to warm. What would be the “symptoms” of this malady? Would we see warming seas? Would we see melting polar ice caps? Would we see a somewhat warmer climate (depending on the degree of internal warming?) Hmmm, sounds almost indistiguishable from what we are seeing!
One more phenomenon however would accompany such a warming. Increased volcanic activity, and increased seismicity.
Are we seeing this? Are we seeing a spike in seismicity and/or volcanic activity?