Why it is urgent to take a proactive attitude towards protecting the extant natural forests

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.

Cited literature

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Cerasoli, S., Yin, J., and Porporato, A. (2021). Cloud cooling effects of afforestation and reforestation at midlatitudes. Proc. Natl. Acad. Sci. U.S.A. 118, e2026241118. https://doi.org/10.1073/pnas.2026241118

Duveiller, G., Filipponi, F., Ceglar, A., Bojanowski, J., Alkama, R., and Cescatti, A. (2021). Revealing the widespread potential of forests to increase low level cloud cover. Nat. Commun. 12, 4337. https://doi.org/10.1038/s41467-021-24551-5

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Lindenmayer, D. B., Bowd, E. J., Taylor, C., & Likens, G. E. (2022). The interactions among fire, logging, and climate change have sprung a landscape trap in Victoria’s montane ash forests. Plant Ecology, 223(7), 733-749.

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

Makarieva, A. M., Nefiodov, A. V., Nobre, A. D., Baudena, M., Bardi, U., Sheil, D., et al. (2023b). The role of ecosystem transpiration in creating alternate moisture regimes by influencing atmospheric moisture convergence. Glob. Change Biol. 29, 2536–2556. https://doi.org/10.1111/gcb.16644

Makarieva, A. M., Nefiodov, A. V., Masino S. A. (2023c) How to assess and preserve the climate-regulating function of forests for local and global wellbeing. The Eastern Old-Growth Conference, Geneva Point Center, NH USA, 21-23 September 2023.

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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.