If you had a choice that'd benefit society ... Watch
I think it's a mistake to aim for mere containment, at least in the case of the Islamic State. It has to be defeated, not contained. The quickest, but perhaps not the best, way of doing that is to use NATO ground forces in addition to airstrikes. Suffice it to say, it would be field day for IS recruiters, but it's arguable that the slow crawl to stalemate (which is what's happening at present) is somewhat morally reprehensible.
It's one thing to not act because you can't; it's an entirely different situation in which you refuse to act despite having the capability to do so. And for what? Just to appease the collective conscience of regressive leftists who've no understanding of the causes of terrorism and can always be relied upon to oppose any intervention by default, with little to no regard for any facts.
Of course, any such invasion must be followed by a vastly better occupation than the one which followed the invasion of Iraq in 2003. There will need to be massive deradicalisation efforts both at home and in the occupied countries, followed by a much more gradual handover of power (>20 years). We'd do well to take a few pages out of the books of people like Maajid Nawaz and promote a kind of secular Islam in the region to counter the Wahhabist nonsense that presently has the peoples of both Iraq and Syria under its heel.
As for climate change, the solution is a lot clearer: massive simultaneous investment in both current renewable generation capacity and research into improving energy storage, efficiency and nuclear energy. And all this has to be done alongside a huge reduction in carbon-based sources of energy. The political aim of this, which ties in with the issue of terrorism, is energy independence. The sooner we can kick the Saudis' collective asses to the kerb, the sooner we can get back to a state of relative security.
Some of the inequality in the world is innate in the fact that there will always be some groups / peoples / nations that are the producers of goods & services, and some who relatively consume much more than they produce. As such, more wealth will sit in the hands of the producers than the consumers.
Also, one thing I realise is that if tomorrow everyone in the world had the same wealth, for a period of time theft would skyrocket, because if you rob all of someone's possessions you can potentially double your wealth, and it would be a very quick way to put yourself into the world's wealthiest.
If you use NATO, then there is a risk of a full scale war in my opinion, I may be wrong, plus a lot more westerners would retaliate and join IS, defeating it full on has cost ramifications financially as well as the lives of civilians domestically and internationally being at risk
As far as cost is concerned, I don't think that money is that substantial an issue in a military alliance like NATO, whose whole defence strategy is to pool the military resources of all its members. Not to mention that the finances are the last thing to worry about when dealing with a genocidal rogue state. They have to go, whatever it takes.
Civilians are already dying; leaving the IS alone (with the exception of limited airstrikes) isn't going to improve that.
So how can every person on the Earth live in a home and receive an income? Poverty is always going to exist.