Trees sequester carbon, so planting more trees will help relieve climate change, right? Well, sort of.
We all know at this point that Terra has come down with a serious fever. We also know whose fault that is. The two most popular, knee-jerk responses to climate change are lower carbon emissions and plant more trees. But how much will those solutions actually help?
For sure at least a little. But here's the thing: fevers are complicated. When someone comes down with a fever, it's in response to an infection that's killing their cells. The raised temperature is supposed to exceed the infectious agent's limits on what conditions it can survive in and therefore kill it. The amazing thing about living beings is that they can regulate their internal state - a process called homeostasis - to survive in harsh conditions such as heat. But there's always a limit. A person can survive in 38 C desert heat but will boil at 100 C. A person's cells can tolerate even less - a fever above 43 C will kill.
The same goes for Terra. She's endured everything from temperatures so high Antarctica becomes a tropical forest to freezing ice ages that would make arctic foxes shiver. She's quite the hardy organism. But there's a difference: the changes were balanced. It'd be like a person getting the flu; evolutionary processes kept her system in balance and ultimately she'd recover. But ice ages don't form in decades. Human-caused climate change does. And that's a problem, because it looks like Terra is reaching the limit on what she can tolerate.
You see, there are fevers that a good night's sleep will take care of, and then there are fevers that will kill unless the doctor takes quick action. Terra seems to have the latter.
If she had the former, planting trees would probably be enough. But with the latter, it might not be. After all, your immune cells can do great things, but not if the temperature gets so high their internal processes begin to shut down. The same is beginning to happen with trees and forests overall.
Thanks to two new studies from Science and Ecology Letters, we now have greater insight into just how the biosphere, and especially trees, are handling the rising temperatures and increasing droughts. The studies focused mainly on forests in the USA and Europe. They also created an interactive map where you can explore the results of the studies and see how forests will fare in the 21st Century under different conditions.
As it turns out, photosynthesis - the process that makes trees so good at removing carbon dioxide - is not the main driver of what conditions trees can tolerate, but rather their cellular growth processes. Trees can tolerate high carbon dioxide levels just fine. In fact, high carbon dioxide levels are good for trees, but not as good as they are bad for them. Because of the rising temperatures, droughts, fires, pests, and diseases are rapidly increasing in severity. These threats often kill off the trees before they can sequester significant carbon to have an impact, or at least inhibit their growth and by extension their ability to sequester carbon. It's much like your immune cells overheating as they fight to keep you alive.
Pine beetles have gone out of control and are destroying huge swaths of pine forest, especially in North America. Red trees are dead or dying from pine beetle infection. Credit: UBC Micrometeorology, Wikimedia Commons, CC-BY 2.0. Generic.
More pine beetle destruction. Credit: Pine Beetle Kill, Wikimedia Commons, CC-BY-SA 2.0. Generic.
Wildfires in Greece on 10 August, 2021. More like these will occur if climate change continues to spiral out of control. Credit: Public domain.
Skies are turning red all over the world because of rampant wildfires, which are the product of out of control climate change and drought. This one was in Oakland CA, USA. Credit: J. Healey, Wikimedia Commons, CC-BY-SA 4.0. International.
That means that even if we do plant trees, the droughts and other threats may prevent them from growing as fast as they otherwise would, which means more time for carbon dioxide levels to rise which means more droughts, etc., which means slower growth - and the cycle continues on. It would be like administering antibiotics and injecting more harmful bacteria in a person at the same time. The antibiotics are only going to help so much if the bacterial population doesn't stop increasing. The same goes for forests.
All this goes to show that we can't rely on forests alone to help with climate change and the destruction that comes with it. The best course of action at this point is to lower carbon emissions as much as possible as well as end deforestation and plant new forests (although we need to make sure they have high biodiversity). If we can stop pumping out so much carbon dioxide, then methods such as planting trees will be much more effective.
One thing we absolutely need to keep in mind is that much of the modern problems of climate change are a result of killing off the organisms that Terra would otherwise use to keep conditions in check. If humans weren't killing off everything, climate change might not have been such a big problem in the first place. That is, climate change is a symptom, and not the disease.
We also need to keep in mind that it doesn't have to be this way. Terra doesn't have to suffer like this. Our niche in the ecosystem is to keep her healthy and beautiful (and happy, if she's sentient), so let's dutifully fulfill our role as stewards of the biosphere and, using solutions like the ones given above, cure her of her cancer. One way you can help by spreading the word.
You can read the original articles here: (Cross-biome synthesis of source versus sink limits to tree growth) and here: (Future climate risks from stress, insects and fire across US forests).
Source: Trees aren't a climate change cure-all: Two new studies on the life and death of trees in a warming world show why. (2022). Phys.org. https://phys.org/news/2022-05-trees-climate-cure-all-life-death.html