Seeing Forests Through Clouds - A 300-Words Science Haiku
When you are confined within the civilized scientific discourse and can't cry out "It's the biosphere, stupid!"
When you are a scientist, you can’t but read Science and Nature every now and then. While the world outside your window is getting warmer, one day in March 2024 you learn from Nature that climate scientists are in uncharted territory and don't understand what's going on — it’s getting warmer too fast! Considering El Niño and all, they anticipate that the warming could wane by August 2024.
Ten months later, in January 2025, you learn from Nature that the warming didn’t wane, and that the scientists are now debating whether it is accelerating. A new study in Science published in December 2024 by H. F. Goessling, T. Rackow & T. Jung suggests that changing cloud cover may be behind the abrupt warming: as low-level clouds decrease, planetary albedo increases, and the planet warms.
This appears to be an important clue, but as the lead author admits, the reason for the cloud reduction remains a “mystery.” Indeed, cloud cover change has so far been seen as a feedback to CO2-induced warming. Since the CO2 added in 2023 could barely explain a 0.02 degrees Celsius warming (one-tenth of what actually happened), even more questions remain.
What strikes you about these discussions of the mysterious anomalous warming and the role of clouds is that they seem to be coming to us from the distant distopian future, when we have already moved to Elon Musk's colony on Mars and there is nothing around except inanimate nature and its purely geophysical processes. The Earth's living biosphere is not mentioned at all, as if it could not play any role in what is happening.
Wise people observe that Mars may be coming to us faster than we are coming to Mars. On the photo: lands devastated by overgrazing, Central Asia.
Of course, you can express your initial emotions in a blog post. But you also know that Science and Nature welcome thoughtful debate. If you have something to say on what’s published there, you are given 300 words for your comment, which they may or may not publish at their discretion without informing the authors about the grounds of their decisions. Below are 300 words that my colleagues and I submitted to Science that it was not able to publish.
Seeing Forests Through Clouds
Goessling et al. (1) link the record-breaking warming anomaly of 2023 to a global albedo decline due to reduced low-level cloud cover. What caused the reduction remains unclear. Goessling et al. considered several geophysical mechanisms, including ocean surface warming and declining aerosol emissions, but did not discuss the biosphere. We propose that disruption of global biospheric functioning could be a cause, as supported by three lines of evidence that have not yet been jointly considered.
First, plant functioning plays a key role in cloud formation (2–7). In one model study, converting land from swamp to desert raised global temperature by 8 K due to reduced cloud cover (8). In the Amazon, the low-level cloud cover increases markedly with the photosynthetic activity of the underlying forest (9).
Second, in 2023, photosynthesis on land experienced a globally significant disruption, as signalled by the complete disappearance of the terrestrial carbon sink (10). Terrestrial ecosystems, which typically absorb approximately one-fourth of anthropogenic CO2 emissions, anomalously ceased this function. This breakdown was attributed to Canadian wildfires and the record-breaking drought in the Amazon (11).
Third, Goessling et al. focus on changes over oceans, but their maps show that some of the largest reductions in cloud cover in 2023 were over land, including over Amazonian and Congolian forests. Another cloud reduction hotspot is evident over Canada. Besides, precipitation over land in 2023 had a major negative anomaly, −0.08 mm/day (12).
Growing pressure on forests is known to induce nonlinear feedbacks, including abrupt changes in ecosystem functioning (13–15). Feedbacks of similar strength in global climate models are unknown (16). The biospheric breakdown in 2023 may have triggered massive cloud cover reduction facilitating the abrupt warming.
If verified, the good news is that the recent extra warmth could wane if the forests partially self-recover. With the many unknowns remaining, we urge more integrative thinking and emphasize the importance of urgently curbing forest exploitation to stabilize both the climate and the biosphere (17,18).
Anastassia M. Makarieva, Andrei V. Nefiodov, Antonio D. Nobre, Luz A. Cuartas, Paulo Nobre, Germán Poveda, José A. Marengo, Anja Rammig, Susan A. Masino, Ugo Bardi, Juan F. Salazar, William R. Moomaw, Scott R. Saleska (authors’ affiliations at https://arxiv.org/abs/2501.17208 )
In other words, this anomalous warming is so abrupt that it could only have been caused by something equally abrupt. Nothing equally abrupt has been so far detected in the geophysical climate system. The biosphere is a key player in the cloud processes, but do we have evidence that something extraordinary happened to the biosphere in 2023? Yes, we do. Global terrestrial photosynthesis was anomalously disrupted as evidenced by the breakdown of the terrestrial carbon sink.
If the mainstream climate science continues to ignore the biosphere, it won’t end well for either.
Cited references
1. H. F. Goessling, T. Rackow, T. Jung, Recent global temperature surge intensified by record-low planetary albedo. Science 387 (6729), 68–73 (2024), https://doi.org/10.1126/science.adq7280
2. D. F. Zhao, et al., Environmental conditions regulate the impact of plants on cloud formation. Nat. Commun. 8 (1), 14067 (2017), https://doi.org/10.1038/ncomms14067
3. T. Dror-Schwartz, I. Koren, O. Altaratz, R. Heiblum, On the abundance and common properties of continental, organized shallow (green) clouds. IEEE Trans. Geosci. Remote Sens. 59 (6), 4570–4578 (2021), https://doi.org/10.1109/TGRS.2020.3023085
4. S. Cerasoli, J. Yin, A. Porporato, Cloud cooling effects of afforestation and reforestation at midlatitudes. Proc. Natl. Acad. Sci. U.S.A. 118 (33), e2026241118 (2021), https://doi.org/10.1073/pnas. 2026241118
5. G. Duveiller, et al., Revealing the widespread potential of forests to increase low level cloud cover. Nat. Commun. 12, 4337 (2021), https://doi.org10.1038/s41467-021-24551-5
6. R. Xu, et al., Contrasting impacts of forests on cloud cover based on satellite observations. Nat. Commun. 13, 670 (2022), https://doi.org/10.1038/s41467-022-28161-7
7. D. Ellison, J. Pokorný, M. Wild, Even cooler insights: On the power of forests to (water the Earth and) cool the planet. Glob. Change Biol. 30 (2), e17195 (2024), https://doi.org/10.1111/gcb.17195
8. M. M. Laguë, G. R. Quetin, W. R. Boos, Reduced terrestrial evaporation increases atmospheric water vapor by generating cloud feedbacks. Environ. Res. Lett. 18 (7), 074021 (2023), https://doi.org/10.1088/1748-9326/acdbe1.
9. R. H. Heiblum, I. Koren, G. Feingold, On the link between Amazonian forest properties and shallow cumulus cloud fields. Atmos. Chem. Phys. 14 (12), 6063–6074 (2014), https://doi.org/10.5194/ acp-14-6063-2014
10. P. Ke, et al., Low latency carbon budget analysis reveals a large decline of the land carbon sink in 2023. Natl. Sci. Rev. 11 (12), nwae367 (2024), https://doi.org/10.1093/nsr/nwae367
11. J.-C. Espinoza, et al., The new record of drought and warmth in the Amazon in 2023 related to regional and global climatic features. Sci. Rep. 14 (1), 8107 (2024), https://doi.org/10.1038/s41598-024-58782-5.
12. R. F. Adler, G. Gu, Global precipitation for the year 2023 and how it relates to longer term variations and trends. Atmosphere 15 (5), 535 (2024), https://doi.org/10.3390/atmos15050535
13. D. C. Zemp, et al., Self-amplified Amazon forest loss due to vegetation-atmosphere feedbacks. Nat. Commun. 8, 14681 (2017), https://doi.org/10.1038/ncomms14681
14. A. M. Makarieva, et al., The role of ecosystem transpiration in creating alternate moisture regimes by influencing atmospheric moisture convergence. Glob. Change Biol. 29 (9), 25362556 (2023), https://doi.org/10.1111/gcb.16644
15. B. M. Flores, et al., Critical transitions in the Amazon forest system. Nature 626 (7999), 555–564 (2024), https://doi.org/10.1038/s41586-023-06970-0
16. W. R. Boos, T. Storelvmo, Reply to Levermann et al.: Linear scaling for monsoons based on well-verified balance between adiabatic cooling and latent heat release. Proc. Natl. Acad. Sci. U.S.A. 113 (17), E2350–E2351 (2016), https://doi.org/10.1073/pnas.1603626113
17. W. R. Moomaw, S. A. Masino, E. K. Faison, Intact forests in the United States: Proforestation mitigates climate change and serves the greatest good. Front. For. Glob. Change 2 (2019), https://doi.org/10.3389/ffgc.2019.00027
18. A. M. Makarieva, A. V. Nefiodov, A. Rammig, A. D. Nobre, Re-appraisal of the global climatic role of natural forests for improved climate projections and policies. Front. For. Glob. Change 6 (2023), https://doi.org/10.3389/ffgc.2023.1150191
This post is an inspiration. Thank you. There seems to be an informal scientific gag rule in place against recognizing the role of the biosphere in climate, which the media and mainstream climate journalism happily abide with. The tragedy is that if we wait for the climate orthodoxy to release its grip around the narrative on it's own accord, it will likely be too late.
Dear Anastassia,
Thank you for another very stimulating and (for my aged brain) challenging post!
Firstly, by my reckoning you exceeded the 300 word limit by at least 10% (and that is assuming Science editors don't count the title and the references!) I believe this is so important that you should re-submit your comments in an even shorter form. (In the English culture we have the saying, If at first you don't succeed, Try and try again.)
Secondly, I have gone to a number of your other Substack articles and scientific papers as I follow your arguments. I cannot pretend to understand them all, but I am intrigued by the need to understand the level of "dryness" when KP is low and less than KE, which means that attempts at reforestation could lead to lower rainfall. Naturally your research has focused on the Amazon, Europe and Russia/China. My area of concern is southern Africa and I assume that much of Botswana and Namibia (even parts of South Africa) would fall into this dry regime. But I do wonder about the current state of Zimbabwe and Malawi (which are both seriously deforested) as to whether they have already crossed into this "too dry for reforestation" regime?
As you are aware, I am trying to restore the trees in the "wet" part of southern Africa to a density of 20 large mature trees per hectare. I don't want to resort to government pressure to enforce this (mostly because our governments simply don't have the capacity to do it effectively) but instead I want to rely on peer pressure. We do have large areas of sugar cane in southern Zambia (irrigated from the Kafue river) and I have been thinking that these areas could be legitimately exempted from the need to have 20 trees/ha as the cane would be effectively transpiring (and presumably emitting the seeding nuclei that are also important). Am I wrong on this? Would 20 trees per ha transpire so much more than irrigated sugar cane, that we ought to be encouraging sugarcane farmers to at least have some trees on their properties?
Finally, I am intrigued by the work of Wright (mentioned in your Feb 2023 https://doi.org/10.1111/gcb.16644) "The onset of the wet season in the southern Amazon studied by Wright et al. (2017) meets these requirements. It has long puzzled researchers as it occurs 2 months before the major geophysical driver of precipitation at these latitudes: the seasonal migration of the Intertropical Convergence Zone (ITCZ)." I wonder to what extent that is true of our rainy season here in southern Africa? Our rainy season was generally thought to start at the end of October/early November, even though the ITCZ has only been arriving around late December and early January. It is very difficult to make any assumptions (based on the limited data that is generally available for the region) but (in recent years) the rains from late October to Christmas appear to have become less reliable than the rains in January and February. This might suggest that the deforestation of the region has reduced the efficacy of these "pre-ITCZ" rains. (Having said that, in the drought years (of 2016, 2019 and 2024) there was a distinct and severe drought in the middle of this ITCZ period - roughly February - and I don't know to what extent the severity of these hot dry spells could also be blamed on a lack of vegetation, or, more especially, on a lack of water holding capacity in our soils that would prevent the vegetation from sustaining adequate rainfall through a dry period, possibly induced by 'external' forces, like El Nino?)
I am sorry to write such a long "Comment" but I hope that other people, concerned about the effects of vegetation, soil and groundwater on our rainfall will find my questions of interest. Bruce Danckwerts, CHOMA, Zambia