This fallacy is committed a lot by climate change deniers and can be surprisingly hard to spot. Oversimplification has also already found its way into the discussion around CDR.
“CO2 is plant food”
Here is one argument by climate change deniers I read time and again in comments on social media if somebody as much as mentions the fact that CO2 is a greenhouse gas that’s bad for the planet. It’s also relevant in the context of advocating for the removal of CO2 from the atmosphere.
Here it goes: “CO2 is plant food. We need more, not less of it.”
A common variation is: “Farmers blow CO2 into greenhouses for better growth. That proves that more CO2 is beneficial.”
If your first reaction is shell shock and the thought “Wait, that’s true, thinking back to 5th-grade biology I remember that plants need CO2” you are not alone.
And, of course, it’s true, plants need CO2 to grow and under certain conditions, more CO2 supports more growth. The operative term here is “under certain conditions”.
This is where the oversimplification comes in: the world is not a greenhouse. Greenhouses have controlled environments, with just the right amount of water, fertilizers supplying nutrients such as nitrogen and phosphorus that often limit plant growth, optimized temperatures, and pest control. The real world has none of that.
Droughts, fires, floods, not enough other nutrients, and pests hamper the growth of plants and additional CO2 does not make up for these limitations.
It’s like saying that more calcium helps people thrive because it is needed for growth but large amounts of calcium don’t help if the person doesn’t get enough other critical nutrients, vitamins, or minerals.
Here is another example that comes up a lot the second you say “carbon dioxide removal”!
“Just Plant Trees”
Sounds lovely, doesn’t it? Everybody loves trees and the idea of taking a relaxing stroll through the woods appeals to many. In short, trees have a lot of co-benefits.
Thing is, though, that planting trees alone is not enough to remove the CO2 we have emitted and continue to emit. We would need to plant at least a trillion trees to make a real difference, which would take up pretty much all of North America or Europe. There simply isn’t enough land for that, it takes too long for the effects to kick in, and carbon sequestered in trees is not particularly permanent: one wildfire and it’s all back in the atmosphere.
Trees are no doubt an important part of climate restoration because of their capacity for removing CO2 from the atmosphere as well as their many co-benefits. However, saying that we “just need to plant trees” is a gross oversimplification that does not do justice to the extent of the problem we are facing.
With trees and other CDR methods, we need a “Yes, and” approach!
There are other oversimplifications out there and new ones will no doubt pop up. If you encounter one of those oh-so-simple solutions, ask yourself: “Is reality really that simple, or am I dealing with the fallacy of oversimplification?”