Ethereum Network Hashrate is currently: 955 TH/s
Etherecum Classic Network Hashrate is currently: 27 TH/s

Currently with 30MH/s you make $1 per GPU per day with ETC. Prior to any power costs.

If all the 955 TH/s switches to ETC, then the hashrate will become ~ 982 TH/s. Which means the difficulty will go up 36x. So basically the profits go down 36 times.

So $1 per day becomes $0.027 per day before any power costs.

Now lets assume that only half the hashrate are GPUs since the ETH ASICs cannot mine ETC. So 955/2=477TH/s. So ETC Network hashrate will become 504TH/s.

So basically instead of $0.027 per day it will be $0.053 per day. You basically need $0.015 kwh power to make nothing. Nobody except maybe in Iraq got 1 cent power.