The hole and the ozone layer, and climate change are two different issues. The UN and World leaders made an agreement in the late 80s to stop industries using the harmful chemicals that were damaging the ozone and leading to more people getting cancer.

After 30 years of not using them, we've started to see the hole repair itself, and in another 40 years it could be back to normal. So, if current governments were to come together and take action on climate change we could see a positive difference. But yeah, because of how big a deal the whole "climate" is, some of thowe changes will be irreversible. Once ice caps melt, they're not coming back, until there's another ice age!