There's not much to pick from, but have you considered Uruguay? Apparently it's the most "European" country in South America - first one to legalize cannabis in the world, second to legalize abortions and is powered by clean energy.

They have second highest GDP per Capita in SA, only country in SA without partisans, high safety, hdi, large middle class and the ruling party is very leftist with social democrats.

The climate is subtropical, not tropical, but that might be better. That being said, the climate change might make it more tropical, which brings me to the main caveat... in case ALL ice melted and no barrier was built, the capital would sink, which could hurt the socioeconomical situation.

Still, some climate change vulnerability stats show Uruguay as relatively safe. Ultimately it's up to you whether you'll trust humanity to tackle the climate issue. I mentioned Uruguay only because it's an interesting option nobody else mentioned, so there might be better countries like Spain(?)

Disclaimer: I just quickly repeated local Wiki article about Uruguay, some of the above might not be completely correct.