[DennisP]

That's an average including all the mining rewards, it's not actually paid by people issuing transactions. A simple transaction on Ethereum costs about a penny.

I agree the energy consumption of present-day blockchains is a problem; hopefully proof of stake will fix it.

[Mithorium]

http://www.truthcoin.info/blog/pow-cheapest/

regarding proof of stake

[DennisP]

https://github.com/ethereum/wiki/wiki/Proof-of-Stake-FAQ

for counterarguments