Just to give an example of a blockchain approach to this: Ethereum Name Service [1].
If blockchain technology were to become popular and widely used by ordinary people, its already worrying environmental impact would skyrocket, assuming the technology is capable of scaling at all. We need to bring the energy consumption of blockchain technology down to a manageable level, and that means abandoning proof-of-work as far as I can tell.
I keep telling my friends hyped by bitcoin that I do not believe in its future as a currency for real daily exchanges because of this energy consumption problem.
Is there any serious track to address this issue?
Unlike most technologies, I do not see the traditional efficiency gains when the technology gets more mature. It seems inherent to proof-of-work and cannot be improved in this paradigm
Assuming a solution is found, is it possible to "update" Bitcoin?
At a larger societal level, we should definitely be worried about tackling emissions for climate change. For this, very few people are advocating getting rid of energy consumption in our societies. Yes, in the short term, people recommend being mindful of the emissions impact of your lifestyle (e.g. a flight has a large carbon footprint) but in the longer scheme of humanity's development we'll always have greater and increasing energy needs.
With that in mind, a lot of focus has been on using non-emissions producing energy (solar, wind, nuclear, etc.) to mitigate climate change. Seen in this context, bitcoin is agnostic to the source of the energy, and its Proof-Of-Work protocol is fine.
The future for ethereum is proof-of-stake. This project is called Casper and will be in Ethereum 2.0. For Bitcoin most transactions will be off-loaded to layer-2 networks but PoW will remain on the main chain.
It may have failed at adoption, but the problem of decentralizing DNS has been solved.
I am unconvinced that a solution nobody uses counts as a solution to a problem anyone has.
It might just never happen. Until then the "worse is better" rule applies.
I have used ncdns in conjunction with dnsmasq in the past and I am happy that there is a solution out there that works just in case the other fails.
If the very unlikely case occurs and bitcoin stops being a thing there is always the possibility to change the POW algorithm. Until then Namecoin is a solution that works ultra reliably since years and most importantly unlike other solutions it works today.
In the mean time merged mining is the best compromise between rock solid chain security and environmental impact.
Do you assume that if Namecoin were to become super popular, the price of its coin would become very high? I don't see why. Can you explain this assumption?
Namecoins are not Bitcoins, they're not supposed to be used as a currency, so the logic that the popularity of Namecoin would create a huge raise in its price is not straightforward.