That brings us to our original question: What, if anything, have humans been doing that could possibly affect the climate…

Yes, we’ve become “industrialized” and we have been burning a lot of fossil fuel; but for thousands of years, ever since man began to settle and farm, we’ve also been cutting down a lot of trees; over the years, huge swaths of forest have been “cleared” for agriculture, cities, roads, industry, cooking, heating, paper, construction, wood products, the list goes on, and the pace has accelerated over the past two or three hundred years. The Sahara and the Middle East for example, “now mostly hot and barren, were once areas of lush vegetation, lakes and rivers, teeming with large wildlife” (The lost forests of the Middle East - Aljazeera, Sept. 2015). And this observation in The Smithsonian, March 2017: “What really turned the Sahara desert from a green oasis Into a wasteland?” “There is strong evidence that by cutting trees and overgrazing the grasses, they were reducing the amount of atmospheric moisture which produces clouds… this may have triggered the end of the humid period more abruptly than can be explained by orbital changes. These nomadic humans also may have used fire as a land management tool, which would have exacerbated the speed at which the desert took hold.”

Haiti has lost about 98% of its native forests since independence in 1804. Even far-north Iceland lost most of its forests - from about 50% tree cover before the Vikings showed up, now down to about 3% - the trees were cut down for habitation, heating, cooking, and boat building.

The discovery of the Americas by Europeans led to a huge spike in deforestation. In the United States, only about 5% of the original native forests remain (as National Forests) - and even those are not safe (“selective” logging is now permitted).

Worldwide, about a third of the virgin forests have now been completely eradicated. Another third or so have been severely degraded by logging and other human activities and are now but a pale shadow of what they used to be. So we’re now left with maybe one third (if that) of the original virgin forests.

And the carnage continues. At least 5 Billion trees are now cut each year (with some estimates as high as 15 Billion). Just to put that into perspective - let’s say these 5 billion trees have an average trunk diameter of 1ft and length of 30 feet - and we attached those 5 billion trunks end to end and side by side (raft style), we could build a bridge the width of a 10 lane highway from the earth to the moon, every single year! (and the leftover limbs, branches and leaves amount to at least as much biomass as the trunks). This is absolutely mind boggling!

So humans have had, and still have, a MASSIVE impact on the natural environment. And why does that matter when it comes to climate..? It matters because forests play a vital role in the planet’s water cycle, cloud formation, and energy transfer.

The Role of Forests

Solar radiation is absorbed quite evenly by the oceans, and man cannot do much at sea to change that significantly. But it’s a different story on land.

Because of this obsession with carbon dioxide, the focus is usually on the role forests play in the CO2 cycle. Not enough attention has been directed at how forests affect the planet’s moisture distribution patterns which, in turn, affect cloud formation, the planet’s albedo, and the climate.

Forests absorb a huge amount of solar energy (which is transformed into various forms of living matter), thus keeping much of that energy from reaching and warming the ground; they also encourage cloud formation, rainfall, and further growth. Vegetation also releases humidity back in the air (through evaporation and transpiration) which absorbs heat (phase change), adds to the cloud cover, and results in even more rain… That cloud buildup reflects more solar radiation back to space. It’s a natural cycle, a positive feedback loop that helps cool things down. In other words, the interaction between forests and moisture acts as a powerful temperature “damper”  and cooling mechanism. Forests also absorb carbon dioxide, produce oxygen, depollute the air, stabilize the soil, help reduce the risk of flooding, and provide habitat for fauna. Native (untouched) forests also have better resistance to forest fires and recover more quickly afterwards. By destroying (or “thinning out”) our forests, we interfered with all that in a big way.

Decomposition/oxidation (part of the natural forest life cycle), does release some heat, but at such low levels and slow rate that its effect on temperature is immediately cancelled by the cooling effect of evaporation from the same moist decomposing matter.

When we cut down forests, we expose the ground and other surfaces to the sun’s direct rays. On a sunny day, the ground temperature in a grassy field or farmland can be as much as 20C° (36F°) higher than the ground temperature in the woods nearby (readings taken 6 inches below the surface) - and that temperature differential is even greater in built up areas. This hot ground heats up the air in the daytime, and continues to warm it up at night. With the air temperature kept above the dew point, cloud formation and rainfall is drastically reduced, and most of the moisture held in the atmosphere simply moves on to a cooler area, perhaps all the way back to the ocean. True, deforested land has a higher albedo, thus reflecting some heat back out into space, but not enough to outweigh its warming effect on the planet, and nowhere near the cooling effect of clouds and forests.

Loss of forests therefore sets into motion a potentially disastrous string of events: Less vegetation >> warmer dryer air >> reduced cloud cover >> less rainfall >> groundwater and aquifer depletion >> droughts >> wind erosion >> loss of farmland >> further rise in ground temperatures >> desertification (although not all deserts are anthropogenic). Tapping into groundwater for irrigation only delays the inevitable. And when it does rain, the rain is warmer, it flows freely, picking up even more heat from the ground resulting in warmer runoff, warmer rivers, and eventually contributes to ocean warming. And this has been going on for centuries. The end result globally is a warmer climate. And if the planet is already in a “natural” warm-up phase (as it is now), this would tend to accelerate the process  - you could even call it “climate change”.

In a nutshell, forests absorb heat, encourage the formation of clouds, and help keep the planet cooler. Deforestation does the opposite. Yes, most climate scientists do agree that forests and cloud cover affect the climate, but few seem to fully appreciate the synergistic relationship between the two, and the strong link between climate and deforestation (or perhaps have chosen to turn a blind eye to it). This natural interaction DOES explain how human activities may have impacted the climate over the past few hundred years.

Food for thought: Regarding that seemingly “preset” temperature limit of around 25°C… It may be worth pointing out that, in the past, heavy vegetation likely played a key role in stabilizing the temperature at that level. Without that forest cover, who knows by how much we could overshoot that limit…  And without enough vegetation to absorb all that degassing CO2, could CO2 levels also get out of control and exceed what humans and other species can tolerate..? And could degassing oxygen from much warmer oceans render them unfit for marine life?

We do have a geological precedent for that scenario. Looking back 250-300 million years at the Karoo ice age, we see that most of the land vegetation had died off because  the fern-like plants of the Carboniferous did not survive the cold and dry conditions; coincidentally, the super-continent of Pangea was coming together. So we had a vast expanse of land with practically no vegetation. Perfect conditions for runaway warming. The planet’s temperature rose rapidly and overshot its normal high limit (probably well into the 30°C+ range). Those extreme temperatures were the likely cause of “The Great Dying”, when over 90% of land and marine species went extinct. Finally the rains came, likely triggered by widespread volcanic eruptions; and it rained practically non-stop for one or two million years (the Carnian pluvial episode). The planet cooled down and things settled back to normal with new forms of vegetation taking hold - animals evolved and thrived in that environment – this was the beginning of the Triassic-Jurassic period and the age of dinosaurs, and led to the world as we know it today.

A side note on how the bulk of the atmosphere is actually warmed up… It cannot be radiation since more than 99% of the atmosphere is made up of gases that are transparent to radiation; on the other hand, all gases can absorb heat by conduction; and as we saw earlier, energy can be transmitted from RAGs to surrounding gases trough molecular contact. Energy is also transferred to the atmosphere through phase change - evaporation draws heat from the oceans (and other moist surfaces), condensation (cloud formation) releases that heat into the atmosphere. A fourth, less significant mechanism is related to aerosols - fine particles absorb radiation, warm up, and in turn warm up the air molecules around them by conduction; but they also reflect radiation which results in less energy reaching the planet’s surface.

But it’s the temperature of the planet itself (the ground and the oceans) that determines long-term temperatures (the climate) - that’s where energy is effectively “stored”. The atmosphere, due to its low mass and density, and because of convection, simply cannot “hold” very much energy (except for that carried by water vapor and clouds) – case in point: the very rapid air temperature drop in dry equatorial deserts from as high as 50°C in the daytime, to as low as -5°C at night. So a warming atmosphere is only an indication that the planet is warming up. Aside from IR reflected back to the planet by clouds, very little heat is transmitted from the atmosphere back to the planet; warm air in contact with water or moist vegetation (conduction) only encourages more evaporation and phase-change planet cooling).

Deforestation tends to accelerate long-term warming trends by allowing more energy to reach (and get stored in) the ground; reforestation would help slow down that trend (and more CO2 in the atmosphere would give it a boost).

Now, considerably more heat is stored in the oceans (~90%) than is stored on land, but the heat absorption rate of oceans is nearly constant, and human activities have little effect on it, so we can leave that one out of the equation. The one significant variable that can be affected by humans is land mass heat absorption. Deforested, hot, dry surfaces absorb a considerable amount of energy and then warm up the atmosphere (by conduction), and leads to more severe local heatwaves.

There are signs some leaders are beginning to take notice. A number of North African countries have been working on an ambitious re-forestation program they call “The Great Green Wall initiative”, aimed at curbing desertification. And urban planners are beginning to realize that trees do help cool things down. Many large cities (Paris, Singapore, London, etc.) have embarked on extensive tree planting programs to help lower the temperature; and climatologists do agree that reforestation on a global scale would help “fight” climate change - but they’re still fixated on carbon dioxide because, of course, 97%... So most governments still focus their efforts (and waste our money) on fighting CO2.

If trees can cool off cities, then forests can cool off the planet…

The World Economic Forum: “Forests are critical to the health of the planet, but their degradation and loss is destabilizing natural systems on a scale unseen in human history.” "Conserving and restoring degraded forest landscapes is essential to combating global climate change and preventing biodiversity loss.”

Biodiversity

Forests are not just a bunch of trees; they harbor whole ecosystems. So, aside from affecting the climate, destroying forests results in a serious reduction in biodiversity – we are now in the midst of the world’s sixth mass extinction in over 600 million years; and losing species at a rate comparable, and possibly even surpassing, that of “The Great Dying”, 250 million years ago, when more than 90% of all species were wiped out. And this one is manmade. We’re “driving one million species to extinction”, mostly thru expansion of farmland - Nature.

Yes, humans are “meant” to be here, we ARE part of nature and at the pinnacle of evolution. But let’s face it, we have become the most destructive species that ever lived on the face of the earth, maybe not so much by ill intent, but by negligence and lack of awareness. We’ve lost about half of our global land and sea wildlife in the past 50 years alone (WWF), and probably now left with less than 10% of what lived here before we came along.  And if we don’t smarten up soon, we may be next on the list… Nature is not just “nice to have”, it’s our life-support system. This is serious - we need to change direction if we don’t want to fall victim to our own success…

The Guardian: “A new major report by the World Wildlife Federation involving 59 scientists from across the globe concludes that the vast and growing consumption of food and resources by the global population is destroying the web of life, billions of years in the making, upon which human society ultimately depends for clean air, water, food, and everything else. ‘We are sleepwalking towards the edge of a cliff’ said Mike Barrett, director of science and conservation at WWF.”

If we’re serious about “saving the planet” we’d better start tackling that; we need to stop encroaching on natural habitats, and embark on aggressive reforestation and restoration programs. Rich countries need to put in place incentives that will encourage the others to get on board. We may be sitting at the top of the pyramid right now, but if we keep removing its building blocks around the base, the whole thing may collapse. We have to be careful that our extraordinary success doesn’t spell our demise.

“Nature” deserves our respect and admiration… We’re surrounded by millions of amazing creatures and plants, each one of them the product of hundreds of millions of years of evolution - and some even display feelings, emotions, and a certain degree of intelligence! Yes, we are one of them, but it may be somewhat short-sighted on our part to take over the whole planet at the expense of all others. In the early years of Homo Sapiens, being clever and inventive helped our species hunt efficiently, defend itself, and survive; with a sparse population, this had little effect on the survival of other species. Then humans began to settle and “clear” land for agriculture and animal breeding; and as the population grew, we needed more and more land, resulting in a gradual loss of habitat for other species. Hunting is still a factor in some areas, and animals still fear us (Nature Africa), but loss of habitat is the primary cause of the dramatic loss of species we’ve seen over the past few hundred years - and it’s not just the extinction of many species, it’s also a sharp drop in the population of the ones remaining. For example, antelopes are still around, but their number has dwindled from an estimated 35 million to less than 1 million now.  And then, sometimes we kill just because we can, or for the fun of it (e.g. the near extinction of the buffalo in North America in the 1,800’s), or for ridiculous reasons (like catching millions of sharks every year, cutting off their fins, and throwing the bodies back in the ocean to die a slow cruel death… and for what..? To make “show-off” soup! - and still going on today). It’s time we change our ways. We must learn to live in harmony with the rest of nature, not just exploit it… We cannot “save (life on) the planet” while destroying it.

Joni Mitchell… Big Yellow Taxi (Listen / YouTube)

Don't it always seem to go
That you don't know what you got 'til it's gone?
They paved paradise, put up a parking lot.

Let’s not wait until it’s too late...

And from a philosophical angle, we need to stop acting as if we “own” the planet. It doesn’t exist for us alone; other species are not there just to entertain, serve, or feed us; they are here in their own right, and they all play an important role in our ecosystem. We are all interdependent cohabitants.

Actually, much more than cohabitants - we and everything else in the universe are ONE. The impression that we are separate from what’s outside our own skin is but an illusion, a comfortable mind trick useful for survival; somewhat like the belief that our body is made up of solid and liquid “matter”, when in fact, at the sub-atomic level, we and all other living (and non-living) things are essentially made up of umpteen trillions of quantum energy packets*, superbly organized, continuously interacting and meshing with each other with some unknown purpose. The forces that “we’re made of” have somehow “morphed” out of, and will at some point morph back into, the apparently infinite “whole” - a mind-bending and somewhat unsettling notion, but in a way, it’s elegantly and beautifully simple! (*E=mc2 i.e. energy and matter are interchangeable).

Renowned Canadian astrophysicist, scientific advisor to NASA, and philosopher Hubert Reeves put it a little more poetically… “Nous ne sommes que de la poussière d’étoiles…” (“We are nothing more than stardust…”)

And, as some philosophers, scientists, and most “primitive” tribes believe, there seems to be a kind of consciousness, a kind of spirit embedded within all that exists. Our “consciousness” is but an incarnation of that spirit. Einstein (who was not a very religious man) wrote: “A spirit is manifest in the laws of the universe - a spirit vastly superior to that of man, and one in the face of which we, with our modest powers, must feel humble.”

We need to broaden our self-perception to embody everything and everyone around us; if only we could open our minds and realize that We Are (part of) The Environment, and the stars, and the galaxies; we’ve morphed out of IT, we’re experiencing IT for a short, precious period of time, and we’ll morph back into IT - then, taking care of our environment, living in harmony with IT, and even getting along with each other should come say… “naturally”; and self-esteem would take on a whole different meaning.

Let’s resolve to take better care of our selves… 🙂

Hubert Reeves’ most notable quote: “Man is the most insane species. He worships an invisible God and destroys a visible Nature - unaware that this Nature he's destroying is this God he's worshiping.”

And back to earth… it comes down to this: Humankind has two important “issues” to address - wildlife decline (first and foremost) and climate; fortunately, it essentially boils down to one fairly simple solution: forest restoration - it’s all tightly interwoven. The “greens”, the “eco activists”, the environmentalists need to turn their attention away from fighting “Big Oil”, away from pushing so-called “renewables” and “green energy”, and re-focus their efforts on their original green agenda: nature / trees / flora / fauna - in other words, on restoring as much as possible of our lost ecosystems. Simpler. Cheaper. Easier to monitor. And most of all, it’s already been proven to work..!

Check out the dramatic change (video) when a couple in Brazil decided to replant the forest on their large ranch: “The results couldn’t be more stunning!… In just 20 years, the animals and birds came back, the rain has returned, the springs are flowing again, THE TEMPERATURE HAS DROPPED, AND THE CLIMATE HAS CHANGED DRASTICALLY”. This was a “full scale” experiment with real results. So, although it may take centuries for forests to fully mature, it doesn’t take very long to begin to see tangible, positive changes. This little miracle could be replicated all over the world. Every country should be encouraged to embark on a vigorous forest regeneration program - all it takes is the will to do it.

On a larger scale, Nepal has done a commendable job at recovering its lost forests, nearly doubling its forest cover in about 30 years, and now reaping the benefits: rainfall back to normal, fewer floods and landslides, and the wildlife is coming back - giving tourism a boost.

You could look at reforestation as a planet makeover

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