There are people who are alive today, and who won't be next year because of extreme weather events tied to climate change.

And that's before getting into real live issues to do with water rights, habitation, crop resilience to changing weather patterns, energy access and usage. These issues are likely to spark wars in our lifetime (if they haven't already.. Syria and the Arab Spring was tied to crop failures and high food prices). And these issues disproportionately affect the poor living today. Entirely aside from rising sea levels which will compound the damage