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
Really interesting questions, Bruce. As you know, I'm not an expert or scientist, but I'm guessing firm answers to your questions don't yet exist because the research isn't being done. As we see, even when the models fail in their predictions, living processes are still ignored by elite climate science.
Your questions as to whether sugar cane plantations in southern Africa, seems especially important, and brings in the notion of biotic intelligence and memory. If living systems are simply fleshy machines, as seems to be the present perspective of numerical modelling, than one might be able to measure the transpiration over the cane fields and get an answer. But as you mentioned, the "when" of precipitation may be as important as the amount. That the Amazon begins the rainy season two months prior to the arrival of the geophysical onset indicates intelligent manipulation by the forest itself. Makarieva attributes this to the trees' moistening the atmosphere to kick in the biotic pump, if I have it right. So we have to ask, would an indigenous landscape have learned when to transpire for the most effective cloud and rain creation, which a planted sugar cane field wouldn't have the knowledge to do? The same reasoning applies to cloud condensation nuclei. One can assume that an indigenous landscape, evolved in place, would have "figured out" the most effective profile of nuclei to increase precipitation. A planted field of sugar cane would lack that. Plus, a monocrop can be assumed to produce a less diverse array of ccn than a diverse, natural forest or landscape.
If I was a millionaire, I'd send you the money to do a study. Have you checked in with the universities in the area? If we had any sense, there would be an army of researches out in the field trying to answer these very questions.
I like your idea and I would attribute this to the need for self preservation through the ability of plants especially trees to sequester their own water within their physical structure and within their own beneficial symbiotic relationships. A catus is the prime example of this. The advantages of below ground sequestration and sharing would primarily be to increase recycling and sharing of nutrients with the added benefit of porosity and aeration to extend the living zone deeper into the soil. Life creates life as we have witnessed with the rapid expansion of life associated with evolution.
Rob, I don't see Biotic Memory as a plausible hypothesis. I fully agree with Anastassia when she talks about wise (generally indigenous trees) that time their new leaf and so their evapo-transpiration to coincide with the (expected) onset of the rains. As opposed to "stupid" trees (generally exotics) that transpire precious moisture out of season. The same thing is true of some of our crops. I grow barley which is irrigated from May to September - it is a "stupid" crop, in that all it's transpiration is wasted as it happens at an inappropriate time of the year. Although SOME of the evapo-transpiration from sugar is "stupid" (happening at the wrong time of the year) most of it would be happening in our hot months of October and November making it potentially "wise" as it should be able to enhance the water cycle at that point to trigger the start of the rains. I imagine, but would like to KNOW whether that transpiration from sugar cane would be as effective as my target of 25 mature (wise) trees per ha for the rest of the southern African region.
As Theodore states, trees can (and do) decide how much to transpire. Our most famous example (he quotes a cactus) is the Mopane tree. During stress conditions it closes its leaves, like a butterfly, and so saves moisture. THAT is why it is so important to also repair our soils AND restore our water tables, so that these trees CAN fulfill their function.
Regarding University research, I have listed them as one of the main contributors to this project (somewhere in the various papers of the Bring back the Rains page on the www.radio4pasa.com website) as the Universities ought to be able to help us fine tune our policies. Sadly, apart from some of the Universities in South Africa (which is not really that dependent on this part of the climate system) the Universities in Zambia, Malawi and Zimbabawe don't really have the resources they need to be of any significant help. Furthermore, we do not have the time to wait for their answers. As I say (again in many of the articles on that website) time is not on our side. The population of Africa south of the Equator is expected to increase by 200m people by 2040; we are already cutting down our trees (mostly for cooking) faster than they are re-growing, and Climate Change (from whatever cause) will make restoring trees and repairing soils that much more difficult. Only one thing is really certain and that is that we HAVE to change the way we think about our natural resources. Bruce Danckwerts, CHOMA, Zambia
HI Bruce I like to use an example I experienced for a trees ability to soak and store water in hard rain events. We have rainforest trees in a sub tropical garden and on a recent 250+mm rainfall event over 36 hours the ground around the trees which have not received much rainfall up to this point was only wet down to the root system. around the top 10cm, the roots had taken all the water and redistributed it around their whole system. We do have heavily mulched ground but this will only hold up to half its volume in water.
My opinion for crops is less sometimes gives more, growing a smaller amount well offers the potential for higher yields per HA which are sustainable. Sustainability is the key and ground water and vapor pressure differential will heavily impact this key component. In Australia we still clear land without a thought to these two and the marginal increase in short term productivity can be heavily impacted from dryer overall conditions and longer prolonged droughts which are slowly reducing productivity for all and severely impacting continent wide weather conditions.
Interesting observations. 250mm in 36hrs is heavier rain than I experience in southern Zambia. I would think that they must be massive trees that can soak up that quantity of water - but Life IS full of surprises. I try to teach the "less is more" principle all the time with the Small Scale Farmers here in Zambia. They are always planting more than they can manage, so they have crops which range from profitable (their first, early planting) to very unprofitable (their last planting). I believe one of the reasons they plant too much is because of their communal land tenure. If they do not plant a piece of land to a crop, it might get reallocated to someone else. So much to do. It starts with education and showing the rural communities how their decisions (even down to how they cook their food) have an impact on the climate, and therefore on how much rain and thus how much water is available.
The trees were still young at that stage under 10m but semi soft wood and they were quite dehydrated at the time. Your idea about cropping around fruit trees seems a good fit in these circumstances, we have a very small parcel of land in comparison but under fruit trees we have much in pots and under large eucalyptus we have raised and lined garden beds for vegetables this allows root separation while allowing dappled summer light and full sun in winter. The fruit trees benefit from the water and fertilizer and the plants benefit from the eco sprays we use on the fruit trees, mainly citrus in this case. We do need to put up hail netting for the veg patch to protect it from the eucalypts shedding nuts and branches. . I dehydrate and freeze some excess like tomato's etc. as you can safely store large amounts but you do require a stable electrical source. Deep wicking beds allow insitu water storage in the raised beds and I have even seen people fill their raised beds with wood as the first layer as a form of Hugel culture, i just have the overflow slightly above base level. I have tried to convince the government the need for hydrological and ecological substitution when they clear land mainly for grazing, it would be much easier while they have the large machinery in situ to create hydrological and biotic equivalent by slowing and storing water to recreate conditions from the forest that has been removed, they are starting to mulch and spread instead of burn which is a positive as our topsoil's are in poor condition to begin with
Another thing which may be of interest is we use what I call living mulches which are full of wood lice like slaters etc this seems to keep the skinks in good stead and they roam all over the vegetables and fruit trees and help to keep them healthy. All you need is a good coarse mulch and add old with new 1/3 2/3 This also helps transfer mycelium, I have also read that insect frass makes excellent fertilizer which plants can more readily absorb than synthetic fertilizers.
Hi Bruce there is evidence that the forests going into a self preservation mode similar to coral reefs when temperatures are too high, some trees will shed leaves and others will wilt sufficiently to angle their leaves away from the sun, either way this reduced transpiration and condensation nuclei and exposes and dries out the understory which has a negative feed back loop on the system hence the droughts seen in the middle of the ITCZ.
Deforestation yes, but also lowering of the water table due to irrigation and riparian mismanagement as you stated in the last comment. I would be looking into the needs of the trees as from my understanding trees will rehydrate their soil associations with the initial rain before going into more vigorous growth if we can offer this for these regions then we will be priming the system to promoting a positive feed back loop toward rain. Beavers can do it trees themselves used to do it by falling across creeks and rivers to create leaky weirs and hard flow bank overflows. It is well within our capability. I would say the only reason places like the Amazon create their own rainfall before the ITCZ is their ability to sequester their own water. Hope this helps
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.
So you are basically saying that when forests are disturbed by fire or temperature increases associated with land clearing and co2, this induced a lowering of transpiration and precipitation nuclei essential for cloud formation at lower altitudes which then are creating localized climatic heat feed back loops which we see induce greater shut down as plants transfer into a preservation mode of internal management of temperature rather than growth (like coral reefs) creating the more rapid rise in global temperatures. This also may be reversing the biotic pump which further concentrates clouds and rain into limited areas of the ocean and dries these regions further.
I don't pretend to understand most of your work, but I certainly understand that scientists who are schooled in only physics and such machine-like systems would rather ignore the complicated and unpredictable ( to them) life sciences. That seems to be as true today as it was 50 years ago when I was a student.
So as another commentator mentioned; please try again, your points are more important than an editor's ego.
Thank you for posting this. It gives me some hope that there are scientists who dont just see raw data.
As per usual, those of us on this planet are expected to wait for some great technological marvel that will save us all, rather than just doing the sensible thing and planting more greenery.
Read Ground Breaking: soil security and climate change. It provides explanation from soil perspective on importance of landscape and biology as a climate forcing agent.
Thanks for the clarity and insight! It’s getting so you can feel the decline of the biosphere in your bones…
Excellent! Bravo! Well said with learned clarity. I ll work on getting your good words heard. Truth will prevail.
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
Really interesting questions, Bruce. As you know, I'm not an expert or scientist, but I'm guessing firm answers to your questions don't yet exist because the research isn't being done. As we see, even when the models fail in their predictions, living processes are still ignored by elite climate science.
Your questions as to whether sugar cane plantations in southern Africa, seems especially important, and brings in the notion of biotic intelligence and memory. If living systems are simply fleshy machines, as seems to be the present perspective of numerical modelling, than one might be able to measure the transpiration over the cane fields and get an answer. But as you mentioned, the "when" of precipitation may be as important as the amount. That the Amazon begins the rainy season two months prior to the arrival of the geophysical onset indicates intelligent manipulation by the forest itself. Makarieva attributes this to the trees' moistening the atmosphere to kick in the biotic pump, if I have it right. So we have to ask, would an indigenous landscape have learned when to transpire for the most effective cloud and rain creation, which a planted sugar cane field wouldn't have the knowledge to do? The same reasoning applies to cloud condensation nuclei. One can assume that an indigenous landscape, evolved in place, would have "figured out" the most effective profile of nuclei to increase precipitation. A planted field of sugar cane would lack that. Plus, a monocrop can be assumed to produce a less diverse array of ccn than a diverse, natural forest or landscape.
If I was a millionaire, I'd send you the money to do a study. Have you checked in with the universities in the area? If we had any sense, there would be an army of researches out in the field trying to answer these very questions.
I like your idea and I would attribute this to the need for self preservation through the ability of plants especially trees to sequester their own water within their physical structure and within their own beneficial symbiotic relationships. A catus is the prime example of this. The advantages of below ground sequestration and sharing would primarily be to increase recycling and sharing of nutrients with the added benefit of porosity and aeration to extend the living zone deeper into the soil. Life creates life as we have witnessed with the rapid expansion of life associated with evolution.
Rob, I don't see Biotic Memory as a plausible hypothesis. I fully agree with Anastassia when she talks about wise (generally indigenous trees) that time their new leaf and so their evapo-transpiration to coincide with the (expected) onset of the rains. As opposed to "stupid" trees (generally exotics) that transpire precious moisture out of season. The same thing is true of some of our crops. I grow barley which is irrigated from May to September - it is a "stupid" crop, in that all it's transpiration is wasted as it happens at an inappropriate time of the year. Although SOME of the evapo-transpiration from sugar is "stupid" (happening at the wrong time of the year) most of it would be happening in our hot months of October and November making it potentially "wise" as it should be able to enhance the water cycle at that point to trigger the start of the rains. I imagine, but would like to KNOW whether that transpiration from sugar cane would be as effective as my target of 25 mature (wise) trees per ha for the rest of the southern African region.
As Theodore states, trees can (and do) decide how much to transpire. Our most famous example (he quotes a cactus) is the Mopane tree. During stress conditions it closes its leaves, like a butterfly, and so saves moisture. THAT is why it is so important to also repair our soils AND restore our water tables, so that these trees CAN fulfill their function.
Regarding University research, I have listed them as one of the main contributors to this project (somewhere in the various papers of the Bring back the Rains page on the www.radio4pasa.com website) as the Universities ought to be able to help us fine tune our policies. Sadly, apart from some of the Universities in South Africa (which is not really that dependent on this part of the climate system) the Universities in Zambia, Malawi and Zimbabawe don't really have the resources they need to be of any significant help. Furthermore, we do not have the time to wait for their answers. As I say (again in many of the articles on that website) time is not on our side. The population of Africa south of the Equator is expected to increase by 200m people by 2040; we are already cutting down our trees (mostly for cooking) faster than they are re-growing, and Climate Change (from whatever cause) will make restoring trees and repairing soils that much more difficult. Only one thing is really certain and that is that we HAVE to change the way we think about our natural resources. Bruce Danckwerts, CHOMA, Zambia
HI Bruce I like to use an example I experienced for a trees ability to soak and store water in hard rain events. We have rainforest trees in a sub tropical garden and on a recent 250+mm rainfall event over 36 hours the ground around the trees which have not received much rainfall up to this point was only wet down to the root system. around the top 10cm, the roots had taken all the water and redistributed it around their whole system. We do have heavily mulched ground but this will only hold up to half its volume in water.
My opinion for crops is less sometimes gives more, growing a smaller amount well offers the potential for higher yields per HA which are sustainable. Sustainability is the key and ground water and vapor pressure differential will heavily impact this key component. In Australia we still clear land without a thought to these two and the marginal increase in short term productivity can be heavily impacted from dryer overall conditions and longer prolonged droughts which are slowly reducing productivity for all and severely impacting continent wide weather conditions.
Interesting observations. 250mm in 36hrs is heavier rain than I experience in southern Zambia. I would think that they must be massive trees that can soak up that quantity of water - but Life IS full of surprises. I try to teach the "less is more" principle all the time with the Small Scale Farmers here in Zambia. They are always planting more than they can manage, so they have crops which range from profitable (their first, early planting) to very unprofitable (their last planting). I believe one of the reasons they plant too much is because of their communal land tenure. If they do not plant a piece of land to a crop, it might get reallocated to someone else. So much to do. It starts with education and showing the rural communities how their decisions (even down to how they cook their food) have an impact on the climate, and therefore on how much rain and thus how much water is available.
The trees were still young at that stage under 10m but semi soft wood and they were quite dehydrated at the time. Your idea about cropping around fruit trees seems a good fit in these circumstances, we have a very small parcel of land in comparison but under fruit trees we have much in pots and under large eucalyptus we have raised and lined garden beds for vegetables this allows root separation while allowing dappled summer light and full sun in winter. The fruit trees benefit from the water and fertilizer and the plants benefit from the eco sprays we use on the fruit trees, mainly citrus in this case. We do need to put up hail netting for the veg patch to protect it from the eucalypts shedding nuts and branches. . I dehydrate and freeze some excess like tomato's etc. as you can safely store large amounts but you do require a stable electrical source. Deep wicking beds allow insitu water storage in the raised beds and I have even seen people fill their raised beds with wood as the first layer as a form of Hugel culture, i just have the overflow slightly above base level. I have tried to convince the government the need for hydrological and ecological substitution when they clear land mainly for grazing, it would be much easier while they have the large machinery in situ to create hydrological and biotic equivalent by slowing and storing water to recreate conditions from the forest that has been removed, they are starting to mulch and spread instead of burn which is a positive as our topsoil's are in poor condition to begin with
Another thing which may be of interest is we use what I call living mulches which are full of wood lice like slaters etc this seems to keep the skinks in good stead and they roam all over the vegetables and fruit trees and help to keep them healthy. All you need is a good coarse mulch and add old with new 1/3 2/3 This also helps transfer mycelium, I have also read that insect frass makes excellent fertilizer which plants can more readily absorb than synthetic fertilizers.
Hi Bruce there is evidence that the forests going into a self preservation mode similar to coral reefs when temperatures are too high, some trees will shed leaves and others will wilt sufficiently to angle their leaves away from the sun, either way this reduced transpiration and condensation nuclei and exposes and dries out the understory which has a negative feed back loop on the system hence the droughts seen in the middle of the ITCZ.
Deforestation yes, but also lowering of the water table due to irrigation and riparian mismanagement as you stated in the last comment. I would be looking into the needs of the trees as from my understanding trees will rehydrate their soil associations with the initial rain before going into more vigorous growth if we can offer this for these regions then we will be priming the system to promoting a positive feed back loop toward rain. Beavers can do it trees themselves used to do it by falling across creeks and rivers to create leaky weirs and hard flow bank overflows. It is well within our capability. I would say the only reason places like the Amazon create their own rainfall before the ITCZ is their ability to sequester their own water. Hope this helps
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.
So you are basically saying that when forests are disturbed by fire or temperature increases associated with land clearing and co2, this induced a lowering of transpiration and precipitation nuclei essential for cloud formation at lower altitudes which then are creating localized climatic heat feed back loops which we see induce greater shut down as plants transfer into a preservation mode of internal management of temperature rather than growth (like coral reefs) creating the more rapid rise in global temperatures. This also may be reversing the biotic pump which further concentrates clouds and rain into limited areas of the ocean and dries these regions further.
I don't pretend to understand most of your work, but I certainly understand that scientists who are schooled in only physics and such machine-like systems would rather ignore the complicated and unpredictable ( to them) life sciences. That seems to be as true today as it was 50 years ago when I was a student.
So as another commentator mentioned; please try again, your points are more important than an editor's ego.
Thank you for posting this. It gives me some hope that there are scientists who dont just see raw data.
As per usual, those of us on this planet are expected to wait for some great technological marvel that will save us all, rather than just doing the sensible thing and planting more greenery.
Read Ground Breaking: soil security and climate change. It provides explanation from soil perspective on importance of landscape and biology as a climate forcing agent.
Thank you for being persistent and thoughtful in this world, Anastassia.
I have concluded this blog post with your article, Anastassia https://drjohnsblog.substack.com/p/race-against-time