It's all relative. That power would have still come from somewhere if we never used Bitcoin and used fiat instead. Everything needs power it cannot be avoided. I wouldn't worry. There much more harmful things going in than Bitcoin mining power consumption.
I do not think so because more countries now are switching to renewable energies. Solar panels are getting cheaper and more efficient every year. Probably in the future the whole world will be able to use a 100% renewable energy source, it will keep the production cheaper and environment friendly.
Renewable energy is still not a solution for the mining electricity consumption issues.All the solar and wind energy is still very expensive and it isn`t consistent.There are days without any sun and wind.
The problem is not the type of electricity.The problem is the increased consumption.In the future, there will be more powerful computers that will execute more calculations with less amount of energy.
Not yet but it's getting better and better and cheaper and cheaper. There are already projects to bring this idea to reality.