Bitcoin's carbon footprint rises inexorably

As the bitcoin continues to lurch to ever more unsustainable record highs, one other unexpected implication has come to light.
I'm sure that no-one ever even considered the eventuality, but, as more and more bitcoins are created, the difficulty rate of the token-generating computer calculations increases dramatically, and, as a result, so does the electricity usage of the process, to the extent that bitcoin and other cryptocurrencies are becoming wildly expensive to produce, and their carbon footprint are also going through the roof.
Bitcoin "mining" requires the linking together of literally thousands of computers. Estimates of the amount of electricity used in bitcoin mining put it in the region of the equivalent of 3 million US homes, or the consumption of the entire population of Denmark or Ireland (other estimates are significantly lower). And it is increasing rapidly, about 30% inthe last month alone according to one blockchain analyst from PriceWaterhouseCoopers (PwC).
Given that about 58% of the world's large cryptocurrency mining pools are currently in China (followed by the USA with just 16%), and that China still gets 60% of its electricity from coal (although that is changing), the carbon footprint of bitcoin is huge. The PwC analyst mentioned above cautions that, "If we start using this on a global scale, it will kill the planet", which seems unduly alarmist. But one thing is for sure: it is certainly getting more and more expensive to produce cryptocurrencies, as the energy use of the process continues to rise.