Johan Rockström, in the interview below, mentions that a big part of the carbon that that trees capture is actually a stress response, and therefore we should not rely on forests. In fact, he says, some forests already have become a source of carbon instead of being sinks, although we do not know yet exactly the reason. But a healthy planet in equilibrium, he says, takes up as much carbon dioxide in the the photosynthesis as it releases through respiration.
Thanks Lazaros! Yes, interesting point. I think the key point is that we don't know how much buffering capacity forests have. How much more can they take? The net emitters are emitting because of a combination of things, including unsustainable forestry practices, fire regimes that are enabled due to forest modification etc. So it's not that healthy, natural functioning forests are net emitters necessarily, it's that they become net emitters when they have been modified in some way or another. However, if climate change continues to increase fire regimes and disease outbreaks like bark beetle in Canadian forests etc., then we don't know the thresholds of when forests (even unmodified forests) shift from being sinks to sources of carbon. Either way, forests are just part of the toolbox for the carbon problem, given there is so so much more carbon in the atmosphere than there was historically due to fossil fuel use. Cheers!
Great post Jono, I think it's really important that we distinguish between mitigating carbon in the atmosphere that came from land use change and that from fossil carbon. As is referenced in the article below "While the carbon atom in the tree is the same as the carbon atom from burned fossil fuels, that’s where the similarity ends. The fossil carbon the tree is purportedly mitigating is a separate and additional source." So notwithstanding the points you made, its crucial to understand that planting a tree does not mitigate a gram of fossil carbon only the carbon emitted when the tree that was there before was chopped down. https://theconversation.com/were-burning-too-much-fossil-fuel-to-fix-by-planting-trees-making-net-zero-emissions-impossible-with-offsets-217437
Thanks Mike! Very good point. Thanks for sharing. I particularly like your ending: "Deforestation has to be reversed, and more trees must be planted to sequester the carbon emitted through past land-use changes. But planting trees instead of stopping fossil emissions is not the answer. Planting trees as well as not emitting fossil carbon is the only solution."
Cheers to you too, Jonathan! Thanks for the reply.
Johan Rockström, in the interview below, mentions that a big part of the carbon that that trees capture is actually a stress response, and therefore we should not rely on forests. In fact, he says, some forests already have become a source of carbon instead of being sinks, although we do not know yet exactly the reason. But a healthy planet in equilibrium, he says, takes up as much carbon dioxide in the the photosynthesis as it releases through respiration.
What do you think of it?
The part of the interview where he talks about it: https://youtu.be/lLq8e73-FAw?feature=shared&t=895
Thanks Lazaros! Yes, interesting point. I think the key point is that we don't know how much buffering capacity forests have. How much more can they take? The net emitters are emitting because of a combination of things, including unsustainable forestry practices, fire regimes that are enabled due to forest modification etc. So it's not that healthy, natural functioning forests are net emitters necessarily, it's that they become net emitters when they have been modified in some way or another. However, if climate change continues to increase fire regimes and disease outbreaks like bark beetle in Canadian forests etc., then we don't know the thresholds of when forests (even unmodified forests) shift from being sinks to sources of carbon. Either way, forests are just part of the toolbox for the carbon problem, given there is so so much more carbon in the atmosphere than there was historically due to fossil fuel use. Cheers!
Great post Jono, I think it's really important that we distinguish between mitigating carbon in the atmosphere that came from land use change and that from fossil carbon. As is referenced in the article below "While the carbon atom in the tree is the same as the carbon atom from burned fossil fuels, that’s where the similarity ends. The fossil carbon the tree is purportedly mitigating is a separate and additional source." So notwithstanding the points you made, its crucial to understand that planting a tree does not mitigate a gram of fossil carbon only the carbon emitted when the tree that was there before was chopped down. https://theconversation.com/were-burning-too-much-fossil-fuel-to-fix-by-planting-trees-making-net-zero-emissions-impossible-with-offsets-217437
Thanks Mike! Very good point. Thanks for sharing. I particularly like your ending: "Deforestation has to be reversed, and more trees must be planted to sequester the carbon emitted through past land-use changes. But planting trees instead of stopping fossil emissions is not the answer. Planting trees as well as not emitting fossil carbon is the only solution."
And PS: Rod Carr covers this topic well here from a NZ perspective: https://youtu.be/I1_gdvNtGXk?si=zmlJiHAJi6d8eyww