Bombing cities, as France did yesterday, and as the US and Russia continue to do, will only create more radicalization by killing still more civilians. Want to eradicate ISIS?
Step 1: The West should just stop supporting the Syrian insurgency, and stop supporting the Gulf States that are also supporting the insurgency. With the flow of weapons and money halted, rebels will defect, and the ground forces of the secular Syrian regime that the US has been trying to overthrow will be able to push ISIS and Syrian Al Qaeda out of Syria.
Step 2: The US should stop supporting the sectarian Shiite government in Iraq. Only then will that government be willing to compromise with the Sunnis they have been ethnic cleansing for so long, and only then will the tribal Sunnis feel they can afford to turn against ISIS again, as they did in 2006. This will give the Salafists fleeing Syria nowhere to run to.
Just stop constantly making everything worse. Just stop intervening.