Featured Post

Holobionts: a new Paradigm to Understand the Role of Humankind in the Ecosystem

You are a holobiont, I am a holobiont, we are all holobionts. "Holobiont" means, literally, "whole living creature." It ...

Showing posts with label global warming. Show all posts
Showing posts with label global warming. Show all posts

Friday, July 28, 2023

Global Warming Explained by the Virgin Mary





The Madonna of Monte Amiata, ca. 1800 m. asl. This post is obviously fictional, I don’t normally hear the voices of supernatural creatures in my head, but it originated from a real experience, when I climbed all the way to the top of the Amiata mountain and the statue of the Virgin Mary placed there really seemed to me lonely and sad. So I thought She wouldn’t mind a little chat — not meant to be disrespectful. 



Good morning, Madonna.

Good morning.

Ah… are you talking?

What did you expect? Did you want me to cry?

No.. I didn't mean that. But I'm a little surprised.

You know, I would also have many reasons to cry. Look where they put me. On top of this mountain, exposed to all winds, cold, snow, hail, etc. Not to mention the smoke from the restaurants they put just below. But it seemed nice to answer you since you've climbed up here. It's a steep climb.

Ah, nothing in particular. Just a little steep. Anyway, thank you Madonna.

It is a pleasure. 

Listen, Madonna… since I'm here, I wanted to ask you something.

Well, everyone asks me things. There are those who are sick, those who have problems with money, love, and things like that. I'm sorry I can't work miracles for everyone, but I can try. You know. He also does what he can. But He has to keep up with a few billion galaxies. Not to mention the other dimensions of the multiverse. But what did you want to ask me?

I know everyone asks you things. But you see, there's a bigger problem. I don't know if you've ever heard of this thing called "global warming."

Of course. You see, I notice it even from up here, on top of the mountain. There is hardly any snow in winter, and it is much less cold. It's the greenhouse effect caused by carbon dioxide.....

Madonna, do you know about these things?

Well, climate science is not really my field. But, you know, He knows certain things very well and explains how things stand to me. If you knew how long it took Him at the time of creation to regulate greenhouse gases so that it was neither too cold nor too hot. He told me a lot about it. And, speaking of temperatures, have you ever thought about Heaven?

In what sense, Madonna?

Well, in terms of the greenhouse effect, I mean.

Actually, no. I didn't think Heaven really existed.

You know that there are more things in heaven and earth than you can imagine with all your science.

Ah, yes... of course. But where is Heaven, then?

It spans many dimensions, of course, but it also overlaps with the one where you humans live. Let's say that in this particular universe, Paradise is in the upper troposphere. And it's a question of the optical depth of the infrared emission. In other words, it's freezing cold in Heaven.

Well, I can imagine, since it's so high up. But they say it's a place where you feel good. Everyone would like to go. It is not so?

Certainly but, you see, souls live there. And souls are diaphanous creatures. They don't feel the cold. Instead I...

Ah... True. It's the question of the assumption, isn't it?

Well yes. I find myself the only one with a human body in all of Heaven. It's a great honor, sure. But, as I said, it's freezing cold. Luckily my son, good boy, has put up a few clouds-radiators where I usually stay. More oxygen, too. Diaphanous creatures don't need it, but I do. And so I'm a little better. Then, after the Last Judgment, they'll have to think of something else -- they'll all come with bodies, and it'll be a little crowded around here. But He will take care of it.

But is what is happening now on Earth the universal judgement?

No. It's something else. It's a bit like when He forgot the magma to boil in Earth's mantle and a gigantic magmatic province come out. And goodbye dinosaurs! You knew how bad it was!

But you, Madonna, were you already there at the time of the dinosaurs?

Obviously not. But He tells me many things. He is very sorry about the dinosaurs. He told me that the tyrannosaurs had turned out particularly well for him. They were a little aggressive, actually, but they were magnificent animals. But that's how things go. Every once in a while an ecosystem gets out of control. He has all these galaxies to manage. Billions of galaxies, he thinks. Almighty all you want, but he can't keep up with it all.

Ah understood. Perhaps. But, then, what is happening to us now, on Earth?

Have you ever heard of Hell?

Yes, certainly.

You've heard it's a very hot place, right?

Yes, yes. That's what they say.

Well, it is the greenhouse effect.

You mean that...... ?

Exactly this. Warming caused by the greenhouse effect. You are all going to Hell.

Madonna, is it possible?

Perfectly possible. You are creating Hell yourself.

Ah...

Eh.... that's right.

But couldn't put in a good word with....

I can try. But with all the trouble you've made and are making.... You understand why I cry, sometimes, right?

Yes, I see. I think I understand.

But you never know. He's good. It's just that sometimes, even He can't stand it anymore.

Well yes. I imagine.

I'll try, anyway. Maybe he decides to help you out. But if you don't stop doing the things you do, Hell awaits you.

I understand.

And thank you for visiting.

It was a pleasure, Madonna. Thanks anyway. And I'm sorry about the smoke from the restaurants down here.

Don't worry. The way things are, they won't last long. There are no restaurants in Hell.

Monday, June 26, 2023

How is the Great Holobiont Doing? Alive, but not so Well

 



This is a translation of a recent article I published in an Italian newspaper, "Il Fatto Quotidiano." It refers to the Italian situation, but I think it can be interesting for an international readership. Note how I tried to explain the situation in simple terms, remaining within very strict length limits. The article turned out to be popular, but, as usual, I received my daily dose of insults in the comments. It is like this -- people have an inner rage that they need to unleash in one way or another. I can understand them, but I wish they would find a better outlet for their sacrosanct rage.  Above, an image from the recent floods in Emilia Romagna in Italy, mentioned in the article as the cause of a quarrel between believers and unbelievers.


From "Il Fatto Quotidiano


Climate Change: Where do we stand?

By Ugo Bardi June 05, 2023


The environment and climate are not often mentioned in the media, apart from particular moments such as in the case of the controversy that followed the flooding in Emilia-Romagna. However, on longer time scales, we see that concern about climate change is gradually spreading. The latest Eurobarometer data (you can find them at this link) show that 12 percent of Europeans put climate change among their top concerns, with Italy exactly in the middle. This is not so small as it sounds: 10 years ago, only 6 percent of Europeans gave this answer, and in Italy, 4 percent. Even compared to pre-covid times (now remote), this year we gained a couple of "worry points."

The reaction to the perception of a serious problem can be simply to deny that it exists, but it may also be to exaggerate it. This was the case with the flooding in Emilia-Romagna where it was obvious to some that climate change was to blame while, for others, it was all the fault of the Greens, or perhaps the river rodents called "nutria." More generally, it seems clear that the rise in the number of worried people is going in parallel with that of the number of skeptics. The latter are very active in the discussion, albeit at a rather superficial level, with various accusations of conspiracies of the strong powers and reasoning about things like the Alps with no ice in the Middle Ages, and why don't you consider the effect of the sun, and then today it is raining, so what? On the other side, the reaction is not so much better. "The IPCC says so, hence it's true," or, worse, in Italy there came the proposal to ban by law "climate denialism." 

But instead of launching into talk of conspiracies or invoking censorship, shouldn't we try to better understand what we are talking about? Climate science was not invented by the WEF in cahoots with the Lizard People. And climate models are quite a different matter compared to the two hand-drawn curves that were used as an excuse to lock us at home at the time of the pandemic. Climate science has more than a hundred years of history of studying a difficult and complex subject and is now one of the most active and fruitful fields of study in modern science. It has given us a grand and fascinating picture of the behavior of Earth's climate over a time span of hundreds of millions of years and more. It allows us to interpret how the biosphere was able to survive all this time and to understand how phases of climate instability led to the great mass extinctions. That of the dinosaurs, 66 million years ago, was only one of many and not even the largest. 

Nothing about climate science is beyond criticism. In fact, without criticism, there is no progress. So, let us maintain a healthy skepticism, but let us also avoid destructive polemics that serve only to demonize, not to build. If we take the correct attitude, we see that climate change is not something that models predict for the more or less distant future. It is happening here and now: we can see it, and we can measure it. We have reached a CO2 concentration not seen in millions of years before our time, when temperatures were 4-7 degrees higher than today. And the temperature continues to rise. This year, the development of the condition called "El NiƱo" in the Pacific Ocean is already causing particularly high temperatures, and it could lead to 2023 breaking all historical records. 

The change is already doing us major damage, for example, making Italian cities unlivable in summer unless in conditioned environments. Not to mention the return of mosquitoes, now victorious everywhere. But the worst damage is being done by the tropicalization of the climate, with prolonged periods of drought alternating with periods of heavy rains. That these intense rains played a role in the disaster in Emilia Romagna is at least likely, although rain was certainly not the only factor at play. Add to that the disappearance of snow in the mountains that used to act as a water reservoir in the summer, and you understand the problems that drought brings to agriculture and why there is talk of ongoing desertification for southern Italy, and perhaps not only for the South. 

These problems can only get worse if we continue to behave as we have been doing, which is to ignore the impact of human activities on the ecosphere. CO2 emitted by fossil fuel combustion is probably the main factor causing warming, but others, such as deforestation and loss of biodiversity, have their weight. 

But let's end on a few optimistic notes. The first is that the global transition to renewables is going great. We have passed the $1 trillion per year level of investment in the transition. If we keep it up, we can reasonably hope to get rid of fossil fuels in a reasonable timeframe. Plus, we are seeing some "greening" of the planet, almost certainly caused by the fertilizing effect of CO2 (see this link). So it seems that the goddess Gaia is trying to lend us a hand in avoiding the worst. But we have to work on it, otherwise, the old lady might decide she can't stand us anymore and make us go the way of the dinosaurs.


Sunday, December 4, 2022

How Gaia Saved the Earth from a Cold Death

 


The Goddess Gaia in the form of the winter deity Khione, daughter of Boreas, the North Wind, and the Athenian princess Oreithyia (image by "Nobody-Important"). 

Earth is a fragile planet and it might freeze to a snowball if not taken care of. So far, the Goddess has done a good job at that but, at least a couple of times during the past few billion years, the Earth actually froze. Might that happen again? It seems that we were close to that just a few tens of thousands of years ago. Now, the problem doesn't exist anymore, with humans pumping zillions of tons of greenhouse gases into the atmosphere. And, who knows? Humans could be the tool used by the Goddess to avoid another "snowball Earth." But now we may have too much of a good thing and the Earth risks boiling. Hopefully, Gaia can take care of that, too.   


It is always amazing to realize how complex is the system that we call the "Ecosphere". And how the system's complexity keeps its parameters within the limits needed for life to exist and prosper. It is the concept of "Gaia" as it was proposed by James Lovelock and Lynn Margulis. The ecosystem is in homeostasis and tends to maintain relatively constant parameters by means of a tangle of internal feedbacks, as all complex adaptive systems ("CAS") do. 

But homeostasis doesn't mean perfect stability. The system's parameters may oscillate - even wildly - before the internal feedbacks can bring them back to the "good" values. Sometimes the system gets close to its limits and it may well be that, at times in its long history, the ecosystem risked going over the edge and then Gaia could "die." This seems to be a common destiny for extrasolar planets, as recently argued by Chopra and Linewaver.

A recent paper by Galbraith and Eggleston on Nature starts from these concepts, noting how the concentration of CO2 in the atmosphere never went below ca. 190 ppm during the past 800,000 years. That happened in correspondence with the lowest temperatures ever observed during that period: the planet was going through a harsh ice age.


This figure from a recent paper by Galbraith and Eggleston on Nature shows an interesting fact: the concentration of CO2 in the atmosphere never went below ca. 190 ppm over the past million years or so. Possibly, it touched the danger limit for the ecosystem to survive. For lower concentrations, plants wouldn't have been able to perform photosynthesis and the biosphere would have largely disappeared.

About these ice ages, there is an interesting point related to the system's feedback. The more ice there is, the more reflective the planet's surface becomes (more exactly, the planetary albedo increases). But, the more reflective the planet's surface is, the cooler the planet becomes. So, we have an enhancing feedback that may transform the whole planet into a single, frozen ball: "snowball earth". It has happened, although possibly not completely, at least twice in the history of Earth. It was during the period we call, appropriately "Cryogenian," from 720 to 635 million years ago. It was not a real "snowball" -- not all of Earth was covered in ice. But what was not under the ice was a frozen desert. To give you some idea of the fascination of this subject, here is an excerpt from the abstract of a paper by Hoffmann et al. on "Science"

"....the small thermal inertia of a globally frozensurface reverses the annual mean tropical atmospheric circulation, producing an equatorial desert and net snow and frost accumulation elsewhere. Oceanic ice thickens, forming a sea glacier that flows gravitationally toward the equator, sustained by the hydrologic cycle and by basal freezing and melting. Tropical ice sheets flow faster as CO2rises but lose mass and become sensitive to orbital changes. Equatorial dust accumulation engenders supraglacial oligotrophic meltwater ecosystems, favorable for cyanobacteria and certain eukaryotes. Meltwater flushing through cracks enables organic burial and submarine deposition of airborne volcanic ash. The sub-glacial ocean is turbulent and well mixed, in response to geothermal heating and heat loss through the icecover, increasing with latitude. Terminal carbonate deposits, unique to Cryogenian glaciations, are products of intense weathering and ocean stratification. "

Can you imagine the Earth in these conditions? A wasteland of dry deserts and ice sheets. At that time, there were no multicellular creatures and life may have survived in hot pockets, maybe volcanic lakes, where it was still possible to find liquid water. 


We may have been dangerously close to a new snowball Earth episode during the past million years or so. Not a trifling matter because today the ecosphere is much more complex than it was at the time of the Cryogenian. A new snowball Earth would likely cause all vertebrate lifeforms to go extinct. It is not just a question of being too cold: the limit of concentration of CO2 that permits plants to perform photosynthesis at a reasonable rate is considered to be around 150 ppm, at least for the most common kind of plants. Under that value, all multicellular plants die, and with them all animal life. Only single-celled creatures could eke out a precarious existence in those conditions. 

But something prevented the ice sheets to expand all the way to envelop the whole Earth and, at the same time, prevented the CO2 concentration to go below 190 ppm. What was that? Several hypotheses are possible. Galbraith and Eggleston favor a biological one, saying that:

In terrestrial ecosystems, carbon fixation by plants is limited by low ambient CO2 (ref. 31). On this basis, ref. 12 proposed that CO2-limitation had significantly reduced plant-mediated silicate weathering during low-CO2 intervals of the past 24 million years, thereby enforcing a lower bound on the ocean–atmosphere carbon inventory over >10^5 yr timescales. Subsequent experiments have been consistent with this ‘carbon starvation’ mechanism, showing reduced weathering by tree-root-associated fungi under low CO2 (ref. 32). Although the feedback on silicate weathering would appear too slow to play a role on the 104 yr timescale of glacial CO2 minima 30, it may be possible that strongly reduced weathering rates lowered ocean alkalinity (thereby decreasing CO2 solubility) on a millennial timescale. Alternatively, reduced photosynthesis rates during the LGM (last glacial maximum) would have slowed the accumulation of terrestrial biomass14, consistent with estimates for lower terrestrial primary production rates33. By slowing the accumulation of carbon in vegetation and soils, this would have provided a stabilizing feedback via an increase of the ocean–atmosphere carbon pool.

Complicated stuff, right? But, basically, the idea is that CO2 is slowly drawn down from the atmosphere by a reaction with rocks (silicates), forming carbonates. This reaction is called "weathering" and it is favored by plants, whose roots provide a good environment for it to take place. Fewer plants, less CO2 drawdown. At the same time, a smaller global biomass means that the quantity of CO2 stored in it becomes lower and this extra carbon most likely ends up in the atmosphere as CO2. So, there are two feedbacks embedded in the system that tend to stabilize its temperature. But, as you may understand from the text by Galbraith and Eggleston, it is even more complicated than this! In any case, these stabilizing geobiological feedbacks oppose the ice/albedo feedback and tend to slow down the glaciation before the two sides of the ice sheet touch each other at the equator. 

But suppose that the Earth really became the snowball that some studies claim to have observed: how did it recover? If it is frozen, it is frozen. Maybe not completely dead, but poor Gaia was reduced to a minor sprite inhabiting hot springs. How could Earth return to the lush ecosphere we are used to?

There is an explanation: it is because volcanoes do not care whether the Earth's surface is frozen or not. They continue pumping CO2 and other greenhouse gases into the atmosphere. Again from Hofmann et al. 

“If a global glaciation were to occur, the rate of silicate weathering should fall very nearly to zero (due to the cessation of nor-mal processes of precipitation, erosion, and runoff), and carbon dioxideshould accumulate in the atmosphere at whatever rate it is releasedfrom volcanoes. Even the present rate of release would yield 1 bar ofcarbon dioxide in only 20 million years. The resultant large green houseeffect should melt the ice cover in a geologically short period of time”[(69), p. 9781]. Because Snowball Earth surface temperatures are below the freezing point of water everywhere, due to high planetary albedo,there is no rain to scrub CO2(insoluble in snow) from the atmosphere."

Note one subtle detail: if temperatures were to go below the freezing point of CO2 (-78 C) even in small regions at the poles, that would form a nearly infinite CO2 sink. And that would be "snowball forever" -- maybe it would have made the Goddess Khione happy, but it didn't happen. Possibly, that was too cold even for a Winter Goddess!

In any case, it seems that CO2 was pumped into the atmosphere by volcanoes, maybe it was the work of the volcanic form of Gaia, the goddess Pele, known for her habit of taking lava showers. 

When the CO2 concentration arrived at levels hundreds of times those of the present-day atmosphere, the result was a cataclysmic rapid collapse of the glaciers and a rise in temperatures. Not only the Earth's ecosystem was saved from a cold death, but it rebounded spectacularly: it was now the time of the "metazoa," the formal term indicate animals. There came the Cenozoic, in which we are still living, with its incredible variety of lifeforms when plants and animals colonized the continental lands. 

You see how the job of Gaia is not so simple. it involves a delicate balance of many factors. Some tend to stabilize the system, while others tend to destabilize it. During the past 15 million years or so, cooling factors took the lead and slowly pushed Earth to lower and lower CO2 concentrations and, with that, lower temperatures.

 Image from Wikipedia Commons. The x scale is in million years from the present. Note the rapid cooling of the past million years or so.

We do not know exactly what caused the cooling, there are several theories. But one thing is sure, Gaia started feeling that it was too cold for her, even in her form of Khiome, goddess of ice. She could die and, this time, perhaps for good. 



So, it became imperative for Gaia to mobilize some of the geosphere carbon and push it into the atmosphere in the form of a greenhouse gas that would warm the Earth back to comfortable temperatures. The Goddess Pele was too slow for that, maybe she is now a little tired after blowing CO2 into the atmosphere for four billion years. So, maybe Gaia thought of a more creative solution. 

Why not use those clever monkeys which had just evolved in Earth's savannas to dig carbon out of Earth's crust, combine it with oxygen, and then pump it back into the atmosphere?  It worked: in just a few hundred years, the monkeys managed to bring back the CO2 concentration to the levels that were typical of Earth as it was a few tens of millions of years ago. 


It may be that, now, Gaia faces the opposite problem: those monkeys have pumped so much CO2 into the atmosphere that now we risk pushing the planet on the opposite side of a climate collapse, to a "hothouse Earth" that might kill the biosphere. Something like that happened with the great extinctions at the end of the Permian and the Cretaceous. Alas, life is difficult, but Gaia can cope. Does that mean getting rid of those pesky carbon-burning monkeys? Maybe. After all, Gaia is a Goddess, she ought to know what she is doing and she has no qualms when it is time to do what's to be done. She can find ways.