Fixing global warming - can't be done anytime soon, but slowing the rate of warming by limiting CO2 emissions, well, just upgrade infrastructure with an eye to low emissions, as described here:
http://newclimateeconomy.report/
Also talks about removing subsidies to fossil fuel producers and refiners. I think we can also mandate higher-mileage cars. No need to pay $100's of billions in offsets.
As you said, subsidence is responsible for relative rises in sea level. But the global rise in sea level continues, and is accelerating, see here:
http://ocean.nationalgeographic.com/ocean/critical-issues-sea-level-rise/
It won't be pointless to stop this global rise in sea levels, that will affect everyone, everywhere.
But look - the far more important question is this - why do you do this for money? Why do you take money to spread lies on forums and in comments? You obviously are a smart person, you can do a lot of things that are worthwhile, and that you can be proud of. But you choose to earn money by lying instead.
My guess is because you think "everybody does it", conservatives and liberals are both out lying as hard as they can, and you're just a soldier in a holy war - or something like that.
Even if that is true, it doesn't make it right. You're still a paid liar, even if the other side might sometimes try the same thing. But you know they're not trying as hard, you know that the conservative side has been working this kind of lying harder and longer, and has been much more successful. Your side is winning. Does that feel good?
What do you tell your family when they ask how work went? What do you tell your kids when they ask what you do? I guess lying is an option.