The CO2 fertilization effect or carbon fertilization effect suggests that the increase in of carbon dioxide in the atmosphere increases the rate of photosynthesis in plants. The effect varies by species and availablity of water.
From a quarter to half of Earth's vegetated lands has shown significant greening over the last 35 years largely due to rising levels of atmospheric carbon dioxide.
One related trend may be what has been termed “Arctic greening.” Scientists have been finding, of late, that as northern portions of the planet warm up even as total atmospheric carbon dioxide increases, there’s been an increase in plant growth in these regions.
Studies led by Trevor Keenan from the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) show that, from 2002 to 2014, plants appear to have gone into overdrive, starting to pull more carbon dioxide out of the air than they have done before. The result was that the rate at which carbon dioxide accumulates in the atmosphere did not increase during this time period, although previously, it had grown considerably in concert with growing greenhouse gas emissions.
Deficiencies of zinc and iron
Reserachers report that the CO2 levels expected in the second half of this century will likely reduce the levels of zinc, iron, and protein in wheat, rice, peas, and soybeans. Some two billion people live in countries where citizens receive more than 60 percent of their zinc or iron from these types of crops. Deficiencies of these nutrients already cause an estimated loss of 63 million life-years annually.