It pays for itself in dollars but what about the carbon emissions?
If they were going to heat using an electric space heater, it's a wash.
If they were going to heat using natural gas, but the electricity comes from nuclear, it's lower carbon.
If they were going to heat using natural gas, and the emissions are higher. BUT, if they were going to run the mining rig anyway, and they've merely turned off the gas heat, the emissions are overall lower.
Heat pumps work by moving heat, they usually move more heat than input energy.
Basically, a refrigerator is a heat pump. The input energy runs the heat pump, which it uses to move heat out of the refrigerator. Typically, for every watt of electricity, more than a watt of electricity is moved out of the refrigerator.
They work by compressing gasses into fluids, and then letting the fluid expand back into a gas. Basically, when a fluid evaporates, it absorbs heat as potential energy. The energy can be harvested by compressing the gas at a high enough pressure that it condenses into a fluid. Do this in a loop, and you can move heat.
No laws of physics violated!
Suppose you built a shed around the outdoor unit of a central air conditioning system and let it come up to max ambient temperature. Then right next to it you built a shed with a resistive heater which consumes the exact same wattage as the air conditioner. The first shed will be much warmer because you're not creating heat so much as you're moving heat. If you increase the resistive heater's wattage by about 2.5x then the sheds will be about the same temperature.
* Don't actually do this and expect the system to survive.
Unfortunately they care. For now only poor face real consequences of climate change. They are to poor to mitigate its effects.
No you don't, when permafrost melts it causes ground to move. It is really bad for everything build on or in it. Something like houses sinking and falling apart. In some cases it cause big holes in the ground and they got even bigger over time.