Substack is great in connecting like-minded people, but I’ve been finding that this close connectivity, while emotionally fulfilling, tends to create isolated bubbles of thought that then begin to evolve separately. Such bubbles risk clashing and canceling each other out when they ultimately collide through a shared reality. I am thinking in particular about the many people concerned about climate change. Even within this community of concerned Earth’s citizens the views on what should be done to help us out of the crisis differ vastly and often radically.

Today I will share a few ideas on how to shape a discourse that recognizes a major role of biospheric and water cycle disturbances in recent climate disruptions but at the same time respects a major role of added carbon dioxide in the observed global warming. In the proposed framework, more people may hopefully get a chance to listen to and hear each other.

Let us first take a look at the familiar narrative.

The familiar, straightforward message is that all our climate problems can be traced to carbon emissions, so to solve them, we must stop emitting. Biodiversity conservation is the poor cousin in the family of dominant narratives about global change. Attempts have been made to link ecosystem preservation to carbon storage, but these have not worked well—either on practical or even logical grounds. If we view ecosystems not as a complex climate-regulating process but merely as a stock or source/sink of carbon, then natural ecosystems are rendered unnecessary and can be replaced with ever-growing carbon sticks to be harvested and buried.

While the biodiversity crisis is often formally attached to climate concerns—for example, as Rob Lewis noted, the tragic story of the mother whale carrying her dead calf, which had starved due to fish shortages caused by dam construction, was reported in the paper’s climate section—our concern for other living beings is readily sidelined when other climate-related interests take precedence. The problem is not just about cutting trees to make place for wind turbines or solar panels but about large-scale resource extraction, including for renewable energy infrastructure and electric-powered devices. These projects require road construction and often lead to widespread decimation of wild nature.

An alternative narrative, which can be characterized as embracing nature’s complexity, can be formulated as follows.

In this more sophisticated framework, it is acknowledged that rising atmospheric CO₂ contributes to planetary warming. It is also recognized that natural ecosystems act as buffers against unfavorable climate fluctuations. While the biosphere cannot prevent an asteroid from striking Earth, it can maintain planetary homeostasis—provided the biosphere itself remains free from structural disruptions, whether internal or external.

This homeostasis can be quantified in various ways, for example by analyzing how temperature fluctuations evolve over time. Without a climate stabilizer, these fluctuations would follow a random walk model, increasing in proportion to the square root of time.

Another way to formulate the idea of natural ecosystems buffering climate disruptions is through the concept of climate sensitivity. Climate sensitivity describes how much our planet warms in response to a given increase in atmospheric carbon dioxide, e.g., its doubling.

For the same amount of added CO₂ we may observer a smaller or larger temperature change, i.e., a lower or higher sensitivity, respectively. The climate sensitivity of the past climates is not very well-known because temperature changes are irregular, and observations are not perfect. For modern climate change, global climate models provide a wide range of climate sensitivities that range by several times, from about two to nearly six kelvins per CO₂ doubling.

If you were a storyteller, how would you visualize and communicate the climate sensitivity concept ? I tried hard and here’s what I came up with.

Imagine the guy in the picture is CO₂, pushing the Earth to the right—toward warming. However, this path is also an uphill climb, which makes it more difficult. The familiar narrative is simple: more CO₂ means more warming.

How do natural ecosystems alter this scheme? The low sensitivity situation means that it is very difficult for the guy to push the planet toward warming, because the slope is very steep. This steep slope is the buffer that natural ecosystems provide.

When we destroy the buffer, climate sensitivity increases. Now, even a small amount of CO₂ is able to push the planet significantly toward dangerous warming. With less natural biota, the same amount of CO₂ leads to more warming. This doesn’t mean that accumulating atmospheric CO₂ is unimportant—I share the concerns of Professor Ugo Bardi, who argues that higher CO₂ levels may even impair our already limited thinking capacity. But by shifting from the left to the right picture, we are quite literally undermining our own existence.

Now, to put some empirical flesh on the bones of our new concepts, we need to address three key questions. First, are there physical mechanisms through which natural ecosystems influence climate sensitivity to CO₂ accumulation? Second, are natural ecosystems in decline? (They are.) And third, is climate sensitivity increasing? (It is.)

We do know that natural ecosystems are powerful regulators of clouds. Clouds are the most complicated element of the climate system because clouds can both warm and cool the planet. They cool by reflecting sunlight, so less solar energy is ultimately converted to heat. They warm because clouds, like CO₂, interact with thermal radiation from the surface and partially redirect it back to the surface, so they are part of the greenhouse effect. As a simple rule of thumb, thick low clouds cool, while thin high clouds warm.

By using these climate levers, it is possible for the biota to regulate surface temperature. Extensive research shows that forests, and not just trees but the whole community of species including fungi and bacteria, emit certain particles that can facilitate cloud formation.

The left graph shows the frequency of shallow convective clouds (those that cool the surface) over different land cover types. These clouds form more often over forests, a pattern observed across all regions of the world. Whether in the Amazon, Eurasia, or North America, forests respond to warmth by producing white cloud shields that help maintain a habitable environment.

The second graph shows that not everything green works right. The blue symbols indicate that cloud cover increases with forest productivity. However, highly productive non-forest ecosystems, such as agricultural lands, generate significantly less low cloud cover, as shown by the purple symbols. The more we extract from an ecosystem—whether through timber harvesting or food production—the fewer resources it has to stabilize itself, the surrounding environment, and climate.

It’s almost hilarious that, in the global change discourse, we still tend to view life merely as a physical-chemical system, even though we know that information governs everything. We’ve embraced artificial intelligence and supercomputers, yet when faced with the ultra-super-hyper computer of life itself, we reduce it to simple chemical reactions—CO₂, carbohydrate production—little more. This perspective is not only flawed but also dangerous.

This outdated view—treating life as a simple physical-chemical process—is also embedded in climate models through oversimplified parameterizations. It comes as an intellectual atavism, a relic of our failure to fully appreciate the complexity of the world.

Returning to the link between natural ecosystem decline and increasing climate sensitivity: The rather dull-looking graph below may not seem engaging, but it encapsulates the drama unfolding on our planet. Over the past century, we have been rapidly losing primary ecosystems—both forests and non-forest landscapes—while simultaneously polluting the atmosphere with CO₂.

The two green curves illustrate a critical reality: we have been dismantling the very system that could have helped mitigate much of the undesired effects of global change. In parallel, the warming has been accelerating. The warming rate has almost doubled in 2010-2023, from 0.18 °C/decade in 1970-2010.

Global surface temperature relative to 1880-1920 is the GISS (Goddard Institute for Space Studies) analysis through October 2024. I am absolutely fascinated by the vast wealth of information that, for the first time in human history, we have about our planet. It’s up to us to ensure this knowledge doesn’t go waste but instead catalizes a phase shift in how we appreciate our living planet._

This increasing climate sensitivity remains unexplained. Moreover, those global climate models that began predicting more warming were downgraded in reliability, as they could not accurately explain the past climate change. We noted as follows:

Global climate models with an improved representation of clouds display a higher sensitivity of the Earth's climate to CO2 doubling than models with a poorer representation of clouds. This implies more dire projections for future climate change, but also poses the problem of how to account for the past temperature changes that are not affected by the model improvements and have been satisfactorily explained assuming a lower climate sensitivity. The concept of the environmental homeostasis and the biotic regulation of the environment provide a possible solution: the climate sensitivity may have been increasing with time—reflecting the decline of natural ecosystems and their global stabilizing impact.

There is another important issue:

Any control system increases its feedback as the perturbation grows. Therefore, as the climate destabilization deepens, the remaining natural ecosystems should be exerting an ever increasing compensatory impact per unit area. In other words, the global climate price of losing a hectare of natural forest grows as the climate situation worsens. We call for an urgent global moratorium on the exploitation of the remaining natural ecosystems and a broad application of the proforestation strategy to allow them to restore to their full ecological and climate-regulating potential.

To stop the destruction of natural ecosystems, we need to cooperate globally. This global cooperation does not have to take the form of a rigid, hierarchical correlation—like the relationship between organs in an animal body. Rather, it can be a loose, interconnected network, like the leaves of a great tree. Each leaf functions independently, consuming light on its own, yet all are sustained by nutrients and water flowing through the shared stem. A shared global understanding of the importance of natural ecosystems could guide us toward realistic local solutions for their preservation. If we just halt their destruction right now, we can prevent further deterioration, which, in itself, would be a significant achievement. And this would buy us time.

Linked literature

Arnscheidt, C. W., & Rothman, D. H. (2022). Presence or absence of stabilizing Earth system feedbacks on different time scales. Science Advances, 8(46), eadc9241. https://doi.org/10.1126/sciadv.adc9241

Dror, T., Koren, I., Altaratz, O., & Heiblum, R. H. (2020). On the abundance and common properties of continental, organized shallow (green) clouds. IEEE transactions on geoscience and remote sensing, 59(6), 4570-4578. https://doi.org/10.1109/TGRS.2020.3023085

Hansen, J. E., Kharecha, P., Sato, M., Tselioudis, G., Kelly, J., Bauer, S. E., ... & Pokela, A. (2025). Global Warming Has Accelerated: Are the United Nations and the Public Well-Informed?. Environment: Science and Policy for Sustainable Development, 67(1), 6-44. https://doi.org/10.1080/00139157.2025.2434494

Heiblum, R. H., Koren, I., & Feingold, G. (2014). On the link between Amazonian forest properties and shallow cumulus cloud fields. Atmospheric Chemistry and Physics, 14(12), 6063-6074. https://doi.org/10.5194/acp-14-6063-2014

Makarieva, A. M., Nefiodov, A. V., Rammig, A., & Nobre, A. D. (2023). Re-appraisal of the global climatic role of natural forests for improved climate projections and policies. Frontiers in Forests and Global Change, 6, 1150191. https://doi.org/10.3389/ffgc.2023.1150191

Moomaw, W. R., Masino, S. A., & Faison, E. K. (2019). Intact forests in the United States: Proforestation mitigates climate change and serves the greatest good. Frontiers in Forests and Global Change, 2, 449206. https://doi.org/10.3389/ffgc.2019.00027

Biotic Regulation and Biotic Pump is a reader-supported publication. To receive new posts and support my work, consider becoming a free or paid subscriber.

How much wild nature do we need and do we really understand how it functions?

As the New Year 2025 opens its horizons, please allow me to offer a few thoughts for discussion. The concept of biotic regulation provides a distinct perspective on why we need wilderness. There is the carbon-centric view: we believe that we need trees to absorb CO2 from the atmosphere. Strictly speaking, this view is not about wilderness or nature at all, because its logical extension is to cut down trees (understood as “carbon sticks”) and bury or burn them to make room for new sticks.

Another view is that we need wilderness to maintain biodiversity, the number of species on Earth. This view has its own controversies. If you take boreal and temperate forests, for example, they don’t have as many species as tropical forests. We can safely conserve all of their species locally, say, in Scandinavia. Does that mean that the remaining wilderness in the boreal forests doesn’t need to be protected?

The proposition stemming from the biotic regulation concept is that we need to protect natural self-sustaining ecosystems in an area sufficient for them to perform their climate-regulating function on a regional and global scale. That is to say, we should not protect wild nature as an ecological museum. We should protect wild nature as a working mechanism for climate stabilization. It is important to note that since we do not quite understand how the climate system works, we must assume that natural ecosystems will work most efficiently when left without our intervention. We can in no way improve their functioning.

To visualize this idea, imagine that the Earth can have several climate states, not all of which are equally favorable to modern life. With environmental regulation by natural ecosystems, the Earth sits comfortably around 15 degrees Celsius as a global average surface temperature. There is a safe potential pit in this temperature range.

As we disrupt natural ecosystems and impair their climate regulation function, the pit becomes shallower and eventually disappears. If we also add CO2, which pushes the Earth toward a warmer state, we could see a sharp and unfavorable increase in global average surface temperature.

The scenario shown in the above two graphs is certainly radical*, but it conveys the concept of why we need wilderness, and how much of it. We need enough wilderness to provide sufficient stability for all the environmental parameters we care about. In simple words, to ensure that the potential pit of our existence is comfortably deep and favorably situated in the parameter space. (E.g., precipitation in a desert can be stably near zero, but this is not the type of stability that we would appreciate.)

Of course, it is not just about temperature and precipitation. It is, in the words of Chuck Pezeshki, an ultra complex multidimensional optimization problem. Natural ecosystems simultaneously optimize biological productivity, temperature, humidity, precipitation, cloud cover, continental moisture transport, soil moisture, nitrogen, phosphorus and other critically important biogens, and they also stabilize themselves against internal disruptions (like deadly insect outbreaks).

This last aspect provides clues to the priorities of protection. All ecosystems that are still capable of self-regeneration must be protected from our exploitation as much as possible. Stop taking from them. They are our gold standard, our ultimate treasure. Efforts to define this important concept of ecosystem self-sustainability, for which we do not even have a suitable expression, are ongoing. We hear about stable forests and high-integrity forests, and in terms of strategies, the outstanding concept of proforestation has recently been formulated. To this intellectual quest, the biotic regulation concept adds the perspective of scale: we need natural ecosystems to do their job of regulating the climate massively around the globe.

So why is protecting natural ecosystems not a major focus of climate negotiations? One reason for our archaically primitive views on ecosystem functioning is that our ecological knowledge is heavily biased toward systems that are severely disturbed by human activity. Such systems are inherently unstable themselves and obviously do not stabilize the environment and climate.

Let us have a look. The graph below depicts the extant intact forests that show no sign of human interference during the satellite era. For what they are worth, these are our proxies for natural self-sustainable forests.

The second graph shows the distribution of flux towers that measure important atmospheric processes and parameters including evaporation, transpiration and transport of tracers like CO2 or biogenic aerosols.

We can see that the vast majority of measurements (translated into the vast majority of publications and the vast majority of students doing their Phd theses about) are made outside the regions occupied by natural forests in areas profoundly transformed (degraded) by anthropogenic activities. I would like to highlight one of the very few points in Siberia (Zotino, the red dot), which Andrei Nefiodov and I visited in 2020. This flux tower is situated in an area surrounded by secondary forests disturbed by clearcuts and legacy fires (see this paper about legacy fires and this one about fire-related landscape traps). Here is a typical view of forests surrounding the tower:

Compare this to an undisturbed boreal forest:

(Photo courtesy of Alexei Aleinikov, the forest did not burn for several hundred (!) years).

The third map below is from a recent global study of ecosystem resilience. It speaks for itself. We do not study natural, self-sustainable, resilient ecosystems. We have excluded them from consideration.

It is like if some aliens were studying human health, and the very capacity of humans as living beings, from inside a big hospital. After studying the patients suffering from various serious diseases, the aliens would conclude that humans are fragile creatures totally dependent on the external supply of medicine and intellectually quite uneventful. They would hardly figure out that humans are able to discover the laws of nature and perform ambitious environmental transformations on their basis. They could deduce very little about the human capacity to create art and would not believe that the best of classical music could have been composed by those strangely morbid apes. Indeed, when we are ill or humiliated, we are far from our best.

Unfortunately, our knowledge about natural ecosystems is similarly heavily distorted. We greatly underappreciate them. Historically, our misconceptions about how natural ecosystems work are so deeply ingrained that we don’t even recognize, let alone understand the importance of, the counter-evidence when by any chance we do stumble upon it. I’ll discuss some conspicuous examples on another occasion. (In passing, I note that seeing the truth in this chaos requires a viewpoint from outside this chaos. Lovelock had such a viewpoint of a space scientist. Gorshkov had such a viewpoint of an outstanding theoretical physicist who additionally spent years in untouched wilderness.)

Here I would like to conclude by listing three goals that I consider worthy of discussion and implementation:

1. Elevate protection of the remaining self-sustainable natural ecosystems, on land and in the ocean, to a top priority in the international climate change mitigation agenda.

   If we lose their climate-regulating potential, we are doomed to a global environmental collapse even under the “zero emissions” scenario.

2. Restore biological productivity on degraded lands, to lessen the anthropogenic pressure on the remaining self-sustainable natural ecosystems.

   The climate-regulating potential of the ecosystem cannot be maximized simultaneously with its economic potential. The ecosystem resources expropriated by humans are diverted from the regulatory processes that become less and less effective.

3. Launch a focused global effort to study the climate-regulating potential of natural ecosystems including

   • soil carbon dynamics
   • ecosystem impact on, and control of, cloud cover
   • ecosystem impact on, and control of, local temperature regime
     *ecosystem mediation of the atmospheric moisture transport as dependent on the degree of ecosystem disturbance.
4. Recognize ecosystem disturbance as a key dimension in the studies of biota-environment interactions. Quantify salient differences in environmental responses of intact versus managed (disturbed, exploited) ecosystems.

To summarize, natural ecosystems are powerful mechanisms of climate stabilization. If we exploit them more, their regulatory function is impaired adding to climate destabilization, including water cycle calamities. Curbing the on-going exploitation of natural ecosystems is feasible and represents a vital part of strategies to mitigate global change.

Words make sense only within the framework of their language. If a language dies, words lose their meaning. In the four-billion-year journey of Life, our civilization is a new word, and wild nature is the primordial language. If we lose our ground base — the wild nature, our civilization will become a chimera, a sand castle that will not last long.

* For interested readers, I discussed how these stability graphs relate to the planetary boundaries in my recent talk at the EcoSummit “Eco-Civilization for Sustainable and Desirable Future” in China (slides here).

What to ask your climate scientist friend about the water cycle and global temperature

In a recent post, “Why It Is Important to Read Scientific Papers Beyond Their Abstracts“, I noted that as the human brain has a limited information processing speed, if most of the incoming information is about carbon dioxide, other important problems of the human predicament, water in particular, will remain dangerously understudied. In my post today, I will add specificity to that statement.

I will discuss two peer-reviewed studies published in the same mainstream journal (Journal of Climate of the American Meteorological Society, AMS) in 2010 and 2021. Both studies use global climate models to address one and the same problem. While they come to opposite conclusions, the later study does not look into the discrepancy with the earlier one. Furthermore, the results of the earlier study, without discussing its discrepancy with the later one, are then used in a 2023 report by the World Resources Institute that aims at a broad audience, including policymakers. None of the studies attempt to approach the problem from first principles, but confine themselves to discussing the outputs of numerical models, for which, therefore, there are no independent constraints.

But first, what’s the problem?

Let us take a look at how we’ve recently changed the face of the Earth.

This graph describes the replacement of primary ecosystems by anthropogenically modified systems (data from Hurtt et al. 2011). Since 1800, the area occupied by primary ecosystems has halved. They no longer dominate over land.

Where natural forests have been replaced by agricultural fields, it looks like this:

One can notice that, deprived of vegetation, the Earth’s surface becomes brighter. Solar energy no longer cascades via complicated biochemical channels to energize the biotic maintenance of environmental homeostasis. Instead, unclaimed by life, it is reflected back into space. Yes, other things being equal, this cools the planet. But what are those other things, and are they equal?

During photosynthesis, green leaves release a lot of water vapor. When a leaf opens to catch a CO2 molecule, water vapor flows out from the leaf’s humid interior into the atmosphere. This process is called transpiration. When forests are replaced by bare fields, transpiration is greatly reduced.

Since our atmosphere can only hold a limited amount of water vapor (which condenses back to liquid when its concentration goes over the limit), precipitation and total evaporation (which includes transpiration) are closely matched on the timescale of a few days. When transpiration is reduced, precipitation is reduced as well.

Our question is as follows. What will happen to the Earth’s mean global surface temperature if we diminish the intensity of the global water cycle by disturbing primary vegetation and reducing transpiration over land? As I discussed in the opening post on this blog, “Global cooling from plant transpiration” (see also the corresponding peer-reviewed study), there is plausible evidence that the effect can be significant. Indeed, given that global evaporation corresponds to a global mean energy flux of 80 W/m2, by decreasing evaporation by 20% over half of the land, we could perturb this flux by about 3%, or by 2.4 W/m2, which is comparable to the current radiative forcing from CO2. In my view, this question is so fundamental to understanding our climate system that one would expect it to be in textbooks. That is not the case.

Let us look at what the scientific literature has to say and how it approaches this question. The study of Davin and Noblet-Ducoudré (2010) uses a state-of-the-art global climate model (the one used in IPCC scenarios) to compare two hypothetical states of the Earth. In one simulation (FOREST) all land except modern deserts is covered with forests. In another simulation (EVA) all land has the same albedo and roughness as in FOREST, but has a much lower transpiration efficiency corresponding to a grassland.

This suppression of transpiration results in widespread warming on land, see the left panel (EVA-FOREST). Besides, it produces a global warming of 0.24 K.

Importantly, there is not practically any change of the outgoing long-wave radiation between the two states. This means that this global warming from suppressed transpiration cannot be attributed to changes in albedo (e.g., due to changing cloud cover).

The authors attribute this global warming to an "internal redistribution of energy in the climate system". Its nature is not specified — like for example we know that CO2 warms the Earth by trapping thermal radiation, but how does an internal redistribution of energy warm it? Nor any considerations are presented that could independently constrain the magnitude of the resulting warming and validate the model outcome.

Without a deeper understanding, even among the scientists themselves, of what the underlying mechanisms could be, messages based solely on numerical model outputs are circulated and communicated to the public and decision makers. One of the key figures in the 2023 report of the World Resources Institute “Not just carbon” ,

Fig. 2.5 “Modeled CO2, Biophysical, and Net Impacts by Latitude of Global Forest Loss”, is based on the results of Davin and Noblet-Ducoudré (2010). The yellow “ET” bars in the left panel represent the latitude-dependent warming due to reduced evaporation and transpiration as found in their model.

The second study, of Laguë et al. (2021), uses a simpler global climate model where one can freely configure the shape of the continents. Fully suppressing evaporation on a hypothetical land that covers 1/4 of the planetary surface, they also obtain warming on land but a global cooling of -0.4 K. Warming over land is more than compensated by cooling over the ocean.

The authors attribute this global cooling to there being less water vapor in the atmosphere, and hence a lower greenhouse effect, when evaporation is suppressed. While they mention the 2010 study in a row of studies addressing similar problems, they do not discuss the discrepancy between their own study and the earlier one. In the 2010 study, evaporation was also suppressed, but apparently this did not produce a lower greenhouse effect, since the planet warmed as a whole.

Imagine for a moment that one study in an AMS journal reported warming from increased CO2, and another reported cooling from increased CO2 without discussing the results of the former. Yes, it is unthinkable. The second study would not make it to publication in the first place. This is (partly) because, as far as CO2 is concerned, besides numerical models there have always been theoretical considerations based on well established physical principles that allow an independent check on model outputs. With respect to the impact of vegetation on the Earth’s global surface temperature such independent theoretical considerations do not exist nor are there any large-scale efforts to develop them.

This situation is unsatisfactory. If an "internal redistribution of energy in the climate system" can warm our planet, we absolutely need to know whether we understand its nature and get it quantitatively right.

I am positive. At a certain moment people will massively get tired of just trying to decipher the meaning of another simulation produced by an ever more sophisticated climate model and will again champion thinking. Another positive factor could be that, as the models become more and more sophisticated and computationally consuming, fewer and fewer researchers will be able to actually oversee and use them, let alone modify according to their research needs. For the remaining community, a re-prioritization of other research methods, including theory development, will become more attractive. As a recent Perspective puts it,

“State-of-the-art models, observational systems and machine learning are transforming our ability to simulate, monitor and emulate many aspects of land climate. Our scientific understanding, however, has not kept pace, and we now lack robust theories to comprehend the rich complexity being revealed by these advanced tools. Now is the time to change course and underpin models, observations and machine-learning techniques with new theories so that we maintain and advance the deep, mechanistic understanding of land climate needed to meet the challenges of an uncertain future.” (Byrne et al. 2024)

Cited references

Byrne, M.P., Hegerl, G.C., Scheff, J. et al. Theory and the future of land-climate science. Nat. Geosci. 17, 1079–1086 (2024). https://doi.org/10.1038/s41561-024-01553-8

Davin, E. L., & de Noblet-Ducoudré, N. (2010). Climatic impact of global-scale deforestation: Radiative versus nonradiative processes. Journal of Climate, 23(1), 97-112. https://doi.org/10.1175/2009JCLI3102.1

Hurtt, G. C., Chini, L. P., Frolking, S., Betts, R. A., Feddema, J., Fischer, G., ... & Wang, Y. P. (2011). Harmonization of land-use scenarios for the period 1500–2100: 600 years of global gridded annual land-use transitions, wood harvest, and resulting secondary lands. Climatic change, 109, 117-161. https://doi.org/10.1007/s10584-011-0153-2

Laguë, M. M., Pietschnig, M., Ragen, S., Smith, T. A., & Battisti, D. S. (2021). Terrestrial evaporation and global climate: Lessons from Northland, a planet with a hemispheric continent. Journal of Climate, 34(6), 2253-2276. https://doi.org/10.1175/JCLI-D-20-0452.1

Makarieva, A. M., Nefiodov, A. V., Rammig, A., & Nobre, A. D. (2023). Re-appraisal of the global climatic role of natural forests for improved climate projections and policies. Frontiers in Forests and Global Change, 6, 1150191. https://doi.org/10.3389/ffgc.2023.1150191

Biotic Regulation and Biotic Pump is a reader-supported publication. To receive new posts and support my work, consider becoming a free or paid subscriber.

A short intro into biotic regulation

Much of what we know today about forests was already known to our ancestors in the distant past. Forests are sources of food and medicine; they provide wood for building and heating homes. Modern people understand these forest functions equally well – they are part of our economy and commerce. However, with the development of science, people received fundamentally new and extremely important information about the forest. This new information is now also gradually becoming common knowledge, but it still has a long way to go.

First, it turned out that forests and other natural ecosystems impose a huge impact on the global environment and climate in comparison with processes in inanimate nature. One of the first to pay close attention to this at the beginning of the last century was a Russian, Ukrainian and Soviet geochemist Vladimir Vernadsky. According to Vernadsky, living organisms are a “huge geological force” (or indeed “the geological force”) that determines the conditions of their own existence in the biosphere (Vernadsky 1998).

Estimates of life’s huge environmental impact first outlined by Vernadsky were later confirmed by international scientific teams using modern methods of studying the Earth, including satellite data. For example, it was found that terrestrial ecosystems, mostly forests, are responsible for the major part of evaporation on land (Jasechko et al. 2013)[1]. Total solar power used by terrestrial vegetation for transpiration exceeds the power of modern civilization by more than a hundred times (Gorshkov 1995).

In the general case, a huge impact can be constructive or destructive, stabilizing or destabilizing. However it was found that natural ecosystems interact with their environment in a non-random way. A Soviet and Russian theoretical physicist Victor Gorshkov analyzed the available multidisciplinary evidence related to the life-environment interaction (from geochemistry to genetics and ecology) and concluded that they have only one non-controversial explanation: the biotic regulation of the environment. Natural ecosystems regulate the environment maintaining it in a state favorable for life (Gorshkov 1995).

The opposing processes of synthesis and decomposition of organic matter serve as the two levers of biotic regulation. Plants synthesize organic matter; all the other organisms (bacteria, fungi, animals) decompose it. Owing to the huge global power of these processes, even a small imbalance between the rates of biochemical synthesis and decomposition could have destroyed life-compatible conditions on Earth in a very short time. For example, the store of inorganic carbon (carbon dioxide) in the atmosphere, which is of the order of 1000 Gigaton C (1 Gigaton is equal to one billion ton), could have been changed by the biota by 100% in just ten years, because the rate of global synthesis and decomposition are of the order of 100 Gigaton C per year.

However, the atmospheric CO2 concentration has retained its order of magnitude over tens and hundred million years! This means that natural ecosystems have the capacity to maintain this concentration in a suitable for life state compensating deviations from the optimum. In other words, to keep the atmospheric composition stable, the synthesis and decomposition of organic matter must be strictly controlled by the natural biota.

Gorshkov (1995) made a crucial inference that, if the biota is monitoring and synchronizing powerful biogeochemical fluxes on a short term, then it must be exerting a strong compensatory reaction on the modern anthropogenic disturbance of the global carbon cycle. This conclusion is distinct from the implications of the Gaia hypothesis, which implied that the stabilizing biotic impacts are pronounced on a geological timescale and could be “extremely slow compared with current human concerns” (Lovelock 1986). The Gaia hypothesis recognized that the destruction of (some) natural ecosystems could impair the planetary homeostasis. But it did not recognize that the remaining natural ecosystems exert a strong compensatory response to the anthropogenic environmental perturbations. Neglecting this response gives rise to a misleading conclusion that some ecosystems, like boreal forests, may not be indispensable for the planetary wellbeing.

The biotic regulation concept draws a fundamental distinction between ecosystems that retain their climate-regulating function and those that have been disturbed beyond their sustainability threshold and have lost the climate-regulating capacity. This distinction has enabled Gorshkov (1995) to solve the so-called “missing sink” enigma long before this solution was recognized in the mainstream literature (Popkin 2015). The conventional view in ecology had been that natural ecosystems function on the basis of closed biogeochemical cycles (Odum 1969) and can only increase their productivity if the concentration of a limiting nutrient increases. Since terrestrial ecosystems are known to be limited by nitrogen and phosphorus (this knowledge comes from agriculture), no one could have expected that undisturbed forests could increase their productivity and ensure a CO2 sink in response to the rising CO2 concentrations. Why should they? How could they, if there is no matching rise in nitrogen and phosphorus? Finally, even if there were an increase in synthesis, why would not there be a matching increase in the decomposition – especially as the soils are warming and metabolic rates of bacteria and fungi increase?

Therefore, when atmospheric measurements became sufficiently precise to enable an accurate assessment of the global carbon cycle, and it was found that the known sources and sinks do not match, and there is a large missing sink of an unknown nature, there has been a persistent resistance from the ecological and Earth Science communities to ultimately admitting that this sink is mostly ensured by natural forests (Popkin 2015; Makarieva et al. 2023a).

Within the biotic regulation this response was straightforwardly predictable. Natural ecosystems must react to the excessive atmospheric carbon by removing it from the atmosphere and storing it in an inactive organic form. As there is no comparable increase in nitrogen and phosphorus, the excessive carbon should be removed as carbohydrates that do not contain nitrogen and phosphorus (Gorshkov 1986). But only those ecosystems that remain sufficiently intact (least disturbed) should be able to perform such a stabilizing response. Other ecosystems like arable lands should be a source of carbon as their regulatory mechanism has been broken. This is exactly how the changes in the global carbon cycle look like: there is a sink ensured by relatively intact forests (and oceanic ecosystems) and a source from land use and net deforestation (Gorshkov 1995).

Therefore, one can view the anthropogenic disturbance of the global carbon cycle as a planetary-scale experiment that has confirmed the biotic regulation predictions. This has been a very costly experiment for our planet. Its results should be thought through very seriously and practical conclusions made. Carbon is a major life-important environmental constituent, but it is not the only one. Water is a key factor enabling life on land. Thus, as they have been able to regulate carbon, natural terrestrial ecosystems should also be able to regulate the water cycle. This regulation has two aspects: one is the regulation of the cloud cover and another is the regulation of the atmospheric moisture transport.

Recent research has revealed that natural forests possess a strong capacity to modify the cloud cover and moisture transport and stabilize the water cycle (e.g., O’Connor et al. 2021; Cerasoli et al. 2021; Duveiller et al. 2021; Makarieva et al. 2023b). We now know, as did Vernadsky in the beginning of the twentieth century that ecosystems do impose a huge impact on the Earth’s cloud cover and atmospheric circulation – i.e., those very factors that are recognized as the biggest source of uncertainty in current climate models (Zelinka et al. 2020). It will take more time until the stabilizing nature of these impacts will be demonstrated in precise quantitative terms as it has been demonstrated for the carbon cycle. We can wait until the corresponding publications reach a critical mass to apply for a paradigm shift, while natural forests will continue to be destroyed. Alternatively, we can use the results of the “global carbon experiment” and make the logical inference that the natural forests must have evolved a stabilizing impact on the water aspects of climate as they have evolved it for carbon – and then take urgent measures to preserve these efficient climate regulators. This will require, in the words of Nassim Nicholas Taleb (2007), “intellect, courage, vision and perseverance”.

As soon as we stand on the position that natural forest have evolved to regulate climate, we immediately recognize that this climate-regulating capacity cannot be maximized alongside commercial uses. Why? Maximum wood production is not compatible with complex natural selection criteria under which the life-supporting forest-climate homeostasis evolved. Beyond a critical disturbance, forests become unable to stabilize climate and bring water on land via the biotic pump. Plantations and forests disturbed by logging are more prone to fire and contribute to landscape drying, not wetting (Laurance & Useche 2009; Bradley et al. 2016; Oliveira et al. 2021; Lindenmayer et al. 2022; Wolf et al. 2023).

A specific and sufficient network of intact natural forests must be exempted from ongoing exploitation to prioritize their evolved climate-regulating function and bring water to land. There is irreplaceable value in forests that still possess their climate-regulating capacity (now, or in the relatively near future). Natural forests fully restore their climate-regulating function during ecological succession, which takes more than a century (i.e. several lifespans of tree species). In the current climate emergency, losing existing natural forests’ climate-regulation is irrevocable.

Self-grown forests with substantial time since the last large-scale disturbance (old and old-growth forests), are primary targets for climate-stabilizing conservation while protecting other key values (proforestation, Moomaw et al. 2019). Regional, national and international cooperation is required to preserve our wellbeing and common planetary legacy of existing climate-regulating forests. Clear and unbiased interdisciplinary collaboration is needed to identify resource-production areas vs. old-growth and climate-regulating networks (Makarieva, Nefiodov & Masino 2023).

While fundamental science is being advanced, the precautionary principle should be strictly applied. Any control system increases its feedback as the perturbation grows. Therefore, as the climate destabilization deepens, the remaining natural ecosystems should be exerting an ever increasing compensatory impact per unit area. In other words, the global climate price of losing a hectare of natural forest grows as the climate situation worsens. We call for an urgent global moratorium on the exploitation of the remaining natural ecosystems.

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[1] In the process of photosynthesis, the stomata of green leaves open to pick up carbon dioxide from the atmosphere. While the stomata are open, water vapor evaporates into the atmosphere from the internal wet milieu of the leaf. This process is called transpiration. Per each molecule of carbon dioxide fixed, several hundred water molecules can evaporate.