But CO2 is plant food!
Reading time: 2 minutesTL;DR
Yes, CO2 is essential to plants. Too much of anything makes it a poison.
Too much CO2 actually degrades the nutrition of plants we rely on and eventually kills them.
Explanation
Yes we know greenhouse gases cause plants to grow faster and stronger in some environments - that’s why we have greenhouses. That’s not new.
Climate change deniers and delayers love to remind us CO2 is plant food - how could it be harmful? Surely more CO2 will help our crops.
You need to drink water to survive. Every day. But if you drink too much of it you can die. It’s the same with CO2 and plants.
Before the plants die, they decrease in nutritional value. So the same crop yield now delivers poorer outcomes for the people eating the crops. That’s bad.
As with everything there’s great variability here - the impact of CO2 on plants is different depending on the plant.
The oceans
Too much CO2 in the atmosphere causes the oceans to absorb more, which changes the pH level, or the acidity balance. At some point the oceans can’t take any more, and then CO2 in the atmosphere just goes up even faster.
So even if our increased atmospheric levels of CO2 were great for plants, we can’t ignore the impact it’s having on the oceans.
Alumni
Another short list of geniuses who’ve assured us that we’ll be fine because CO2 is plant food.
Former Australian Prime Minister Tony Abbott. “There’s the evidence that higher concentrations of carbon dioxide – which is a plant food after all – are actually greening the planet and helping to lift agricultural yields.” Oct 2017
Australia’s wealthiest woman, Gina Rinehart. “CO2 is an essential plant food and except in the very high atmosphere, not a greenhouse gas” Jan 2024
Further reading
High CO2 levels will wreck plants’ nutritional value, so don’t plan on surviving on vegetables.
As Carbon Dioxide Goes Up, Plants’ Nutrient Content Declines.
Skeptical Science: CO2 is plant food? If only it were so simple.