why bitcoin mining difficulty is increased?
I just want to knows that why the bitcoin mining difficulty level is increased and i am afraid of the life of future miners.Maybe in future the miners electricity will cost more than our rewards because of the difficulty level.
Main reason why the difficulty is increasing is because on how it was programmed to be mined.
There is a total of 21 million bitcoin to be mined from its inception and on its first four years 10.5 million is scheduled to be mined, and scheduled to decrease by half every 4 years until the last coin is mined. So if before a block is consists of 50 coins then 25 then as of now a block is only consists of 12.5 coins and will be decreased by half again.
To answer your question about its efficiency when it comes to electricity. During the time that a block is consists of 50 coin a coin is only priced for less than $100 and now price is $6000 for a block with 12.5 coin. Since the price per coin is increasing mining is still profitable.