[biker1]

The anthropogenic increase is about 2.5 ppm per year.

Originally Posted by lpkruege1

So, 400 parts per million, is equal to 0.04% of our atmosphere. Plants require CO2 to produce oxygen.
While plants can utilize a range of CO2 levels, the optimal percentage for most plant life is considered to be around 0.03% or 300 parts per million (ppm), which is close to the current atmospheric concentration; however, increasing CO2 levels within a reasonable range can often boost plant growth in controlled environments like greenhouses up to around 1000 ppm.
Key points about CO2 and plant life:
Minimum level:
Plants can still photosynthesize at lower CO2 levels, but their growth will be significantly reduced.
Optimal level:
Most plants experience maximum photosynthetic activity around 300-1000 ppm CO2.
According to research, the minimum CO2 concentration considered necessary for plant life is around 150 parts per million (ppm), below which plants struggle to survive and reproduce effectively; at extremely low levels, photosynthesis would be significantly hampered and plants could die off.

So, this is me analyzing those numbers. If the plants die off below 150 parts per million, and stop producing oxygen, at what level do scientists agree we should we reduce CO2 to? How much CO2 is actually manmade compared to forest fires, volcanos, and other natural releases of CO2?