For a short period I looked into carbon stuff and while forests were good, wetlands were deemed much bigger sinks.

It feels like wetlands is a huge ignored area. If what I read at the time holds (I think it was like 6-12x sequestration rate in some regions), a simple thing like rising sea levels would have a huge impact.

And anthropogenic destruction of wetlands is also a huge issue and one that is relatively easy to reverse in a lot cases (dams, rerouted rivers). And in some cases, water can just be rerouted occasionally to create temperarly wetlands that are good ecosystems as well. Mossy Earth I think is doing some of these.

Strangely enough I have been seeing wetland creation coming up on my radar recently. Hinkley Point C nuclear power station has been proposing these as alternative to acoustic fish deterrent, but the locals who might be affected are not happy.

https://www.bbc.co.uk/news/articles/ckgzwrgv71no

  It would transform the biodiverse habitat into barren, species-poor salt marsh and tidal mud.