But great news to us Paleo and Primalers!
The concept of ocean acidification is pretty bad, what with its causing harm to shelled organisms. This was going to hurt the shellfish industry.
But it turns out that the amount of protein in plants goes down with increasing atmospheric CO2 ppm. This is because the plants cannot assimilate nitrates as easily (which is our main way of fertilizing, btw). This loss of protein slows plant growth and reduces nutrition content.
Carbon Dioxide Enrichment Inhibits Nitrate Assimilation in Wheat and Arabidopsis
The concentration of carbon dioxide in Earth’s atmosphere may double by the end of the 21st century. The response of higher plants to a carbon dioxide doubling often includes a decline in their nitrogen status, but the reasons for this decline have been uncertain. We used five independent methods with wheat and Arabidopsis to show that atmospheric carbon dioxide enrichment inhibited the assimilation of nitrate into organic nitrogen compounds. This inhibition may be largely responsible for carbon dioxide acclimation, the decrease in photosynthesis and growth of plants conducting C3 carbon fixation after long exposures (days to years) to carbon dioxide enrichment. These results suggest that the relative availability of soil ammonium and nitrate to most plants will become increasingly important in determining their productivity as well as their quality as food.
They used ppm's predicted for ~2100 to show this, but also saw harmful effects on crop growth using ppm's similar to what we're going to see in the next 40 years, even assuming some progress on limiting CO2 growth.
This also means that higher CO2 means poison ivy becomes more virulent.