I don't think bitcoin mining has that major impact to the environment, on the daily basis, electricity wastes are already present even before bitcoin has existed, therefore bitcoin is just an adding factor to problems present upon its usage, and merely not the cause of the problem itself.
Indeed, mining is not the main cause nor the major contributor of environmental waste, but it is undeniable that it does leave a substantial amount of carbon footprint that adds up to the already damaged environment we live in.
You see, even producers of mining rigs know this for a fact. That is why we keep on seeing innovation left and right on how to better cool down the systems and make it more process efficient to increase power efficiency too. Big mining setup even produce noise pollution too and this is being address with new designs to lessen both power consumption and noise.
To have mining systems that would use lesser electricity is really a big of a deal as we know that as soon as global adoption starts, pool of miners will sprout all over the world making the damaging effects of mining rigs even more.