The threat is in the form of increasing global warming which results in climate change. Generating Bitcoin requires a capable computer to solve complex mathematical puzzles and high electricity consumption. so that some countries prohibit mining for several other reasons such as in China and Iran some time ago. if so will bitacoin and others be able to run forever or is this just an excuse to change the green field to red..
There is no threat coming from bitcoin mining, LOL, it just began like 10 years ago and now they are saying that it has a dramatic effect on global warning and environment issues. Bitcoin is not the culprit here, many industrial nation since the 1900 has really contributed to the worsening and increase of the earth's temperature. This is just an excuse and I doubt that even 0.1% bitcoin is having a negative effect on climate change.