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..
It can really be damaging for the earth if bitcoin will be mined abusively. Fossil fuel is needed in order for the blockchain to keep on running. If we can remember, Elon Musk used it as his reason to remove bitcoin as a mode of payment for Tesla. Also, most of the countries considers it as one of the main reason why they are not tolerating the use of bitcoin. It is not just an excuse, we may actually feel the pay back soon if ever people would keep on abusing mining. We should make sure that we are only mining enough not to the point that we are hurting the earth because all of our investment would be worthless when the nature gets its revenge.