The amount of energy required for a bitcoin transaction is rather abstract, but the power consumed by each bitcoin transaction can be spent by a single U.S. family for a week, which more or less pollutes the environment...
There is no way to quantify the energy spent on a transaction.
We can have 400 000 or 23 675 transactions a day , the same amount of energy will be spent for mining.
Soon we will be forced in to using greener energy (not from fossil fuels) and then even if the cost of energy required for BTC rises it won't be anywhere near as bad as it is currently. Solar and Geothermal power are far superior to fossil fuels in terms of protecting the environment and these alternative energy sources should soon phase out the heavily polluting methods. In the long run I don't think Crypto will generate that great of an issue for the environment
Greener energy is not cheaper.
It's cheaper because it receives subsidies from the government.
It is also efficient because right now wind farms and solar panels are installed in the best spots.
Like in the first days of gold mining, when gold was found directly in the riverbed.
Once we ramp up the production you will have to put panels in not so efficient places, so the cost will just go up.
The Tree-huggers are all worked up by the amount of energy and electricity that are used by Bitcoin mining, but they forget that Fiat currencies are much worst. These guys get worked up by FUD that are spread in the media and these articles are mostly biased. Can you imagine how much damage is done to the environment to manufacture coins and paper money? How many trees are cut down? Now paper/silk money is being replaced by plastic money in the UK, which is even worst.
Well, let me answer one of your question:
http://www.designlife-cycle.com/us-penny/So the US mint that is servicing 300 million people is pending less than 1/7 of what bitcoin consumed in December and since then with the difficulty skyrocketing we can assume it has grown a lot!!!!
think about it this way..
if we were mining using GPU's the electric used by the network would be much higher but the difficulty(security from brute forcing) would be weaker
that said
the total 23exahash is about 1.8mill S9 miners
however
there are half a million ATMS in america
there are 6700 banks in america, many bank call centres, head quarters
(1.4mill employee's probably with access to a pc each)
then we have the background stuff like visa, mastercard and amex servers
and thats before you equate the fuel consumption of the secure bank note armored delivery vehicles and staff getting to work
and thats before you equate the physical resource consumption of printing bank notes..
if you done some maths you would see moving fiat around uses more electric and is less secure than bitcoin
in short FIAT is less environmentally friendly
So, you add ATMs, banks, call centers, headquarters, their pc...
But you don't add bitcoin nodes, bitcoin atms, the servers that run exchnges, online wallets, and the computers of all 1 million people that have an account on bitcointalk
.
This qualifies for quite a biased view, isn't it?