It's not the same kind of pollution. One destroys the forest, the ground, and still pollutes rivers and air with very toxic elements. The other burns energy and uses hardware. Hard to compare. But today gold mining is still a big concern and to look for more gold we have to destroy more land as you can see in the news.
Could we someday have a way to stop this crazyness by all replacing gold by BTC. Gold would be used for what it is and the pollution and land destruction would certainly decrease.
Maybe there's a way to rebuy gold with BTC according to a schedule so that it's win win win win for everybody.
Also it would probably solves many debates about the future of BTC but that's secondary.
For now a serious article in a peer reviewed journal would for sure have a huge impact and start the process of mass adoption...
And it seems the right time to do it.
Both are very destructive in our environment. When we mine gold, those private owned-miners cut trees in the mountains just to let them mine their, tendency of that FLOOD. In manufacturing electronic gadgets, it also costs minerals such as gold, fossil fuels, silver, copper. Those are to be mine. So its the same process but different in output.