And that right there is your ignorance.
A couple decades ago they figured out CFC's, specifically the chlorine in them, was making it really high up in the atmosphere, where it reacted with sunlight to destroy ozone molecules in an unending chain reaction. The thinning of the ozone layer, and even development of holes in it, was leading to increased UV radiation reaching the ground rather than being absorbed up there in the ozone layer. skin cancer rates were measurably increasing. These CFCs came predominantly from the refrigerants ("freon") we used in these new fangled air conditioners that had popped into use in the recent decades.
Now no one wanted to give up their A/C. It was the single biggest reason people began moving to the sun belt (population exploded down there, where it used to be very sparse). Everyone loves A/C. so instead we did a few things. we developed new coolants there was less reactive. we got better at trapping them and preventing them from escaping into the atmosphere (used to be common to just vent straight into the air before that).
and the result of a world wide effort and fundamental A/C industry changes was that the ozone recovered. it's a natural layer that barring outside influence will develope and hover around a set level on its own. once we figured out what was harming it, and removed that influence it pretty much went back to normal.
We (humanity) did that.
We created a world wide problem.
And then we fixed it.
And people have already forgotten about it.
But there is no reasont o think we can't do it again with GW.
We have the technology right now, today, to end nearly ALL human CO2 emissions.
It would still take several decades for the current trend to slow, stop, and even reverse, but eventually our actions would reach an equilibrium (assuming we havent already passed any of the theorized tipping points that leads to a new, unfavorable equilibrium).
But we could do it.
It's just a matter of political will.
And that's what people would obstruct. From the oil/gas companies who love their money, to the religious folks who think its blasphemy to think we could even affect God's Earth, to the politicians and tea partiers who would rather die young on a dead planet in the name of "Freedom! 'Merica. No taxes! F YA" cause they somehow think fixing it means no feedom at all and nothing but taxes.
Pure greed and ignorance all of it.
We already know what runaway global warming can do. We call it the pre-cambrian extinction event, when nonstop volcanic eruptions in Siberia lasted for thousands of years, causing runaway global warming that eventually killed 98% of all life on earth. Life itself nearly went extinct. (and its rather a miracle that it didnt, and that following events eventually triggered massive cooling that made the planet habitable for life as we know it). And that event, that warming, and the following extinctions, lasted longer than all of current human civilization has existed. And it took millions of years for life to recover and re-evolve.
But still: we could do it.
We could fix this problem before it's too late.
It's not a matter of ability or capability to do it, but simply the will to do so.
Or we oculd sit around with thumbs in our butts and do nothing, calling those who identify the problem and its potential "alarmists" and "radicals", and fear any change or technologies that would enable us to fix the problem.