Forests: do they cool Earth, or do they warm it? A comment by Anastassia Makarieva

 

Anastassia Makarieva, giving a talk. Together with Viktor Gorshkov, she developed some fundamental concepts on the functioning of the ecosphere: the "biotic regulation of the environment" and the "biotic pump." Here, with her permission, I reproduce a message that she sent to a discussion forum on these matters. If you are interested in joining the forum, write me at "ugo.bardi(thingette)unifi.it"

by Anastassia Makarieva

Dear colleagues,

thank you very much for these fascinating discussions. I am learning so much from this group, just to mention a couple of more recent things, thanks Svet for reminding us of those important mice studies, thanks Mihail for the note about agroecology in North Korea and thank you, Christine, for sharing your experiences as a farmer. It is indeed a very hard job, I am no farmer but I lived in the wild where you have to care about most things that are vital, and this job leaves little time for doing science, especially in a cold climate. (you can find some photos here). And I am overwhelmed with more things discussed in the group, trying to catch up, and will write later.

Here I thought that I would share my understanding of whether the forests cool or warm the Earth, I did discuss it a few times so sorry if it is a repetition.

In the review article recently quoted by Ugo, as Mara rightly noted, there is nothing controversial or revolutionary. Everybody knows that when a certain part of solar energy is captured by evaporation, the surface gets locally cooler than in the absence of this process. Just because, by energy conservation, a certain part of solar energy, instead of heating the surface, is spent to extract water vapor molecules from the liquid phase by overcoming intermolecular attraction.

But, importantly, this energy remains in the biosphere -- unlike the part of solar radiation that is reflected back to space by a bright surface.

So, whether the Earth as a whole will get cooler or warmer in the presence of evaporation, will depend on how the biosphere dispenses this latent energy.

Take a look at this figure, above. It shows how condensation occurs in the rising air. The latent heat is released in the upper atmosphere and can radiate to space from those upper layers without interacting with greenhouse absorbers (that are mostly concentrated below). This will serve to cool the planet, by effectively making the planetary greenhouse effect smaller. Once again: a certain share of solar energy will leave the Earth with less interaction with the greenhouse absorbers. It is a cooling effect of evaporation.

Importantly, this effect will be stronger if the warm air spends more time in the upper atmosphere. If it descends shortly after condensation, all latent heat becomes sensible and just warms the surface. But if there is a large-scale circulation pattern with the air traveling thousands of kilometers, the effect will be more pronounced. So the biotic pump circulation will make this effect stronger (more than in a local shower). (*)

But, besides this cooling effect, there are warming effects. One of them is the mere presence of more water vapor in the atmosphere over moist surfaces. Since water vapor is a greenhouse substance, its presence over land increases the concentration of greenhouse absorbers. The share of energy leaving without interacting with them increases, but the total number of molecules increases as well. Which effect will win?

Furthermore, more water vapor and convection mean more clouds. And some of the cloud types warm the Earth. Others cool the Earth. Which will prevail?

These arguments show why the message about cooling by forests will never spring up from global climate models. They are not suitable to estimate whether it exists and how strong it might be.

My personal position is that focusing on cooling or warming is strategically harmful to the forest protection case. What natural forests definitely do is that they minimize the fluctuations of the water cycle, heat waves, droughts, and floods. While these extremes are currently officially attributed to CO2 emissions, it is well-known that this attribution suffers from many problems. I would recommend this short video by Dr. Sabine Hossenfelder https://www.youtube.com/watch?v=KqNHdY90StU on this topic.

So in fact to argue that a particular (LOCAL) heatwave has to do with forest destruction (which is known to severely change LOCAL temperatures) might be much easier and more productive than to argue about the role of forests in global warming or cooling -- where there is no simple argumentation.

So, think how it works now: we have a heatwave, and people are told it is due to CO2 emissions, to cut emissions people use "biofuel" by cutting more forests. With more natural forest loss, the water cycle is further disturbed and we have more heatwaves, which are again attributed to global warming, etc. It is a complex situation.

Anastassia

Anastassia Makarieva: Biotic Regulation in Florence

 

Anastassia Makarieva  (center) receives a gift of appreciation for her talk in Florence, on Dec 11th, 2021, from Nicola and Anna in the form of a jewel made by Nicola, jeweler in Florence.

We had the pleasure of a visit to Florence of Anastassia Makarieva, one of the world's most creative and brilliant scientists in the field of ecosystems. Anastassia, together with Viktor Gorshkov, is the originator of the concepts of "biotic regulation" and "biotic pump" -- both fundamental in our understanding of the functioning of the ecosphere. Together, they mean that the current climate change is only in part the direct consequence of the increase in greenhouse gas emissions, but in significant part the result of the human perturbation of the ecosystem, and in particular the destruction of the old-growth forests. 

So, Anastassia carries a message: it is vital for the planet to keep forests alive and in their pristine state. And that means just what the word says: forests, not just trees. Those politicians who compete for who plants more trees are just doing greenwashing. They may be harming the planetary ecosystem more than helping it. A tree, alone or as part of a plantation, does not have the same balancing effect and water carrying system that a forest has. A message that's not easy to understand for the current generation of decision-makers, used to the concept that a tree is worth only what profit it can provide once it is cut and sold on the market. Nevertheless, we must try to pass this message. 

For Anastassia's talk in Florence, we experimented with a new format of presentation. To have Anastassia give an "official" talk, I should have gone through I don't even know what mass of paperwork, and then her talk would have been attended only by the few academics who still have some interest in creative research. All that in a super-safe, soulless room. The university, nowadays, has become something like Dracula's castle, with the difference that it is a scary place even in the daytime. 

To say that these official seminars can be disappointing is an understatement. A few years ago I organized a talk by a Russian scientist on the question of the supply of gas from Russia to Europe. You would think it is an interesting subject. Well, the attendees were exactly zero, besides me, the sponsor of the talk, and the Russian scientist herself. And at that time there was no Covid yet to make people afraid even of their shadows.   

So, this time we decided to play it differently: a colleague of mine kindly offered her living room to host Anastassia's seminar and we announced it on the social channels in addition to the regular university channels. We also offered drinks and snacks. We didn't know what to expect and we had no idea of how many people would bother taking a trip to the hills near Florence to listen to a Russian researcher speaking in English about her research. 

It was a remarkable success. Not a big crowd, but we collected about 25 persons, of whom only 3 were professional scientists (I think they were those who would have shown up had we organized the talk in the university). And they all listened with extreme interest to Anastassia's talk, fascinated by the story of how the ecosphere stabilizes climate and how the forest's biotic pump creates wind and rain. When it was the time of telling the story of how Anastassia and Viktor survived for months in the boreal forests in a tent, with bears strolling nearby, the audience was completely captivated. The informal party after the seminar was an occasion to build up friendship among people who share the same views of the world, even though they are not necessarily scientists.  

There is something to learn, here. Science is not a Moloch to worship, nor a dictator to be obeyed. And it is not even a conventicle of hyperspecialists who know so much about so little that they can be said to know everything about nothing. Science is one of the several possible embodiments of the concept of "philosophy," the love of knowledge. It is something that does not belong to anybody, it belongs to everybody. And that was clear at Anastassia's talk. 

h/t Benedetta Treves and all those who helped organize this seminar. To know more about the biotic pump and biotic regulation, see the site https://bioticregulation.ru/