While our release of CO2 is definitely increasing, do you have a reference for the second part of your assertion that "photosynthesis, is constantly on the decline with the destruction of forest" ?
30-some years ago, when I looked into this, the biggest contributors to CO2 removal were oceanic: plankton photosynthesis, dissolution in water, calcium carbonate synthesis by various organisms, etc.
Also, it would appear that increasing agricultural yields would offset any forest declines, at least to some degree.
I will have to look up the reference (don’t have time this evening and I’m away from my home library where I think I put my finger on it- will IM later).
In regards to increased levels of photosyntheis via agriculture- I would be hesitant to agree. Acres in crops has declined with increased productivity per acre due to fertilization and modern methods. Also, deforestation is not always, and maybe even seldom, linked to agriculture. Devlepoment and logging may take a big chunk.
Also, I think I remember your comment concerning plankton related photosyntheis being true, or consistent with your comment. However, with increased CO2 production through industrial release, there is no mechanism that increases plankton production for balance.