There is more greenery/forestation, and likely more biomass downstream, but I would expect other effects to cancel those effects beyond certain thresholds. For example, even though plankton and algae might benefit from additional carbon and heat, acidification of the ocean might lead to a net decrease in both.

I guess it would be impossible to actually measure.

Heat could also increase biomass since there would be a longer growing season and higher latitudes opening up.

But like you say, it’s a trade off so hard to predict.

We’ve pumped a lot of nitrogen into the biosphere. I wonder how much that’s increased the total biomass.