That's too broad though, because there been specific issues we've (humanity) managed to come together to fix, like the "ozone hole" stuff being "solved" with re

That's too broad though, because there been specific issues we've (humanity) managed to come together to fix, like the "ozone hole" stuff being "solved" with regulations, protocols and public policy, while there are other issues we haven't quite been able to do the same with, all under the umbrella of "climate change".