Caliphate cannot be declared by a group of terrorists.
The basic requirement of Islamic Caliphate is that it should have control of Makkah and Madinah,
So this guy can claim whatever he likes....
The problem is that the caliph is generally understood to be both the spiritual as well as temporal leader.
Actually the basic requirement is a shurah council of pious people (non existing today of course) who get recommendations and they choose based on that ...Or even voting..
1: Consensus (
ijma'). The Sunnis say that the choice of caliph rests first and foremost on selection by the community, so that if the
ummah elects a given individual as its leader, he must be accepted as such and his commands must be obeyed.
2: The second method consists of Consultation and the exchange of views among the prominent members of the community. Once they agree among themselves on the choice of a leader for the community, his caliphate becomes legitimate and it is incumbent on everyone to obey him.
3: The third method consists of the caliph nominating his own successor. This happened in the case of 'Umar, who was appointed caliph by Abu Bakr without any objection being raised by the Muslims.
Not the first time this century though:
In 2001, Osama bin Laden called upon Muslims to “establish the righteous caliphate of our ummah”, a man who would lead and organise the ummah. A Sunni, he would enforce a single Sharia. The bewilderingly many extant sects and schools of thought would have to vanish, either by persuasion or by coercion. Since Shias obviously cannot be persuaded, they (and others) would have to be subdued.
what's this dude's qualifications? 
