They have to find really cheap power, if you ask me! i want to see 0.01$/KWh! That way they could build a really big farm an mine the hell out of the blockchain. AM isn't a small player, they should go as far as possible and re-claim those 40% in 2015! Also they could continue to offer a cutting-edge cloud mining!
Even if the network wouldn't grow much from today on, claiming 40% of the network possibly means building 100-150MW worth of
new Bitcoin mines in 2015. That's about half of all of Google's capacity (265MW) by power combined. And twice the size of Facebook (78MW). And it remains a moving target during and after.
I had a post here with some numbers I put together recently:
Energy Consumption of the Bitcoin Network
http://bitcointalk.org/index.php?topic=520977.msg9825138#msg9825138