The mantle plume and global warming are two entirely different phenomena . Heat from the Earth's molten core as demonstrated by volcanism ,undersea plumes and the movement of tectonic plates has been a constant unchanging part of how our planet works since it was formed over 4 billion years ago.
Global warming due to Carbon emissions is a VERY recent development.
It started within the last 150 years but has accelerated massively within the last 25 years, and is entirely due to human activity putting extra CO2 into the atmosphere.
The artical just tells us of a previously undiscovered mantle plume that is melting ice under one small area of Antarctica.