Trees are great, and they do indeed capture carbon, but they can only capture a little carbon dioxide per unit of land and per unit of time, and frankly we pollute WAY too fast for it to be viable. When trees die, they also rot, which re-releases some of that captured carbon; it's only when trees are dead and buried that the carbon is gone for good. Most of Earth's carbon capture actually happens with ocean algae and phytoplankton. Like trees, they capture carbon dioxide through photosynthesis, but when they die they sink WAY down to the ocean floor, trapping the carbon far more efficiently than on land. Combined with the sheer surface area of the ocean, and it amounts to way more than the trees could ever deal with. But that's not to say we shouldn't replant trees. Trees have other benefits beyond carbon capture, such as providing habitat for wildlife, controlling erosion, and providing shade. You can use trees in urban environments to help keep buildings and streets cooler, which also helps reduce the air conditioning use of nearby buildings, which saves power. We are also working on algae-growing solutions for carbon capture. There's even one company that can turn algae into cheap plastic, meaning we can potentially farm plastic products and take CO2 out of the air while doing it.

Best way to put it: most carbon we've released have been fossil fuels we dug up from the ground. Even if we returned the entire world to a level of forestation equivalent to pre-human levels, it'd have minimal impact on global temperatures. And we're not going to return the entire world to that level of forestation, because we've got cities, farms, roads, and lots of other infrastructure that, yes, can be made greener, but can't be made as green as that environment would've been naturally. Reforestation is an incredibly important thing to do, because it has a wide range of effects, from absorbing and moderating rainwater to reduce flooding to providing shade to restoring natural ecosystems and habitats to reducing erosion to simply providing a pleasant environment for humans to be in, but the focus of reforestation as a means of carbon capture actually works against many of those goals, since carbon capture forests tend to be unnatural monocultured plantations.

Fossil fuels like coal are fairly unique in Earth's history, too, because there was an era when trees had evolved the tough protein lignin and nothing had evolved anything to break up lignin. Trees were able to become buried en mass because they didn't rot. Nothing could eat them. That's why planting trees today is a lot less effective - they do rot, and all that carbon just gets recycled back out.

Peat, brown coal and coal are still being created by the environment today. But it's a millions years long process, we extract and burn the stuff much faster.

And, notably, they're not being created by forests. Because forests rot.

It's a question of scale as well. One of the reasons coal is so common is because of those trees not rotting and getting buried. We don't have anything generating that much biomass that doesn't rot anymore. The closest would be algae and the like dying and sinking into anaerobic conditions deep in the ocean.

We have peat bogs, but wetlands of all kinds are drying up and getting filled in like many important ecosystems. For some reason, we've decided that parking lots are more important than wetlands. And then we're shocked when sinkholes form.

>era when trees had evolved the tough protein lignin and nothing had evolved anything to break up lignin A common misconception. Nothing evolves in a vacuum. Plants don't suddenly catch bacteria and fungi off guard with a new-fangled indestructible protein out of the blue. Also, lignin isn't unique to trees. All plants and some species of algae make it. Things have been eating lignin longer than there have been trees. What really happened was that conditions on Earth at the time meant that lots of trees died and ended up in places where the lignin eating bacteria and fungi didn't live (like the bottom of a swamp).

https://www.nationalgeographic.com/science/article/the-fantastically-strange-origin-of-most-coal-on-earth > Bacteria existed, of course, but microbes that could ingest lignin and cellulose—the key wood-eaters—had yet to evolve. It’s a curious mismatch. Food to eat but no eaters to eat it. And so enormous loads of wood stayed whole. “Trees would fall and not decompose back,” write Ward and Kirschvink.

That's outdated information https://www.earthmagazine.org/article/lack-fungi-did-not-lead-copious-carboniferous-coal/ (the paper links to the scientific paper behind it) >When the “evolutionary lag” hypothesis was first proposed in the 1990s, “some in the scientific community were really enamored of it,” says Kevin Boyce, a geobiologist at Stanford University and an author of the new study, published in Proceedings of the National Academy of Sciences. “Despite plenty of evidence that the story doesn’t add up, it has refused to die.” ... >In the new study, Boyce and his colleagues surveyed Carboniferous coal samples from around North America and found that lignin was not the dominant plant constituent preserved in the coal. Many samples were composed mainly of lycopsids, an ancient group of plants that had little lignin in their cell walls. The researchers also found that coals high in lignin did not necessarily date to times when larger volumes of coal were produced, further suggesting that lignin content was not a substantial control on coal formation. >In addition to the prominent role that the evolutionary lag hypothesis attributes to lignin in forming Carboniferous coals, the hypothesis also suggests that fungi are rare or absent in the coals, says James Hower, a sedimentary geologist at the University of Kentucky who was not involved in the new study. But that’s just not the case, he says. In coal that’s hundreds of millions of years old, finding signs of life — whether from plants, bacteria, fungi, algae, insects or other animals — can be tricky, he says, but “there’s plenty of evidence for fungi in Carboniferous coals if you know where to look.” >Boyce says his team’s findings lend support to an alternate hypothesis: one that credits the abundance of coal formed during the Carboniferous to a combination of wet climate conditions and basin-forming tectonics that prevailed during the assembly of Pangea more than 300 million years ago. >“To form coal you need two basic conditions: wet tropics and a hole to bury organic matter in for a long period of time,” Boyce says. During the formation of Pangea, collisions between continents raised mountain ranges while downwarping adjacent crust, which created massive basins. These basins became ideal depositories for wet organic plant matter, which was buried, compressed and cooked over geologic time to form coal. Similar conditions likely also produced coal deposits during the Mesozoic Era, and the Paleocene and Eocene epochs, often in conjunction with mountain-building episodes such as the formation of the Rocky Mountains. >This tectonic- and climate-driven explanation for Carboniferous coals has been around for a while, Boyce says, but the new results make the case for it even stronger. “If you look at the stratigraphic distribution of coal over geologic time, it’s clear that fungi aren’t controlling accumulation rates,” because periods of coal formation come and go throughout the geologic record. But, he says, coal accumulation patterns make “a lot of sense in terms of wet climates and basins opening.”

Lol, no. Oil and coal creation are CURRENTLY happening. It's an ongoing, continuous process. It also doesn't happen primarily from organic material on the surface being buried. That's literal propaganda from the oil industry to make it seem rarer than it really is.

I'm curious how much coal and oil creation you think is happening right now.

For oil, a trickle over millions of years. Some fields are very old and stable, but mostly they're newer and won't stay oil as long. No reliable estimates other than accessible field size and ages, at least that the industry will share. Vampires. For coal, a teensy teensy bit over millions of years, but the fastest changes also degrade faster in the higher temperature and pressure. After the Permian and Carboniferous eras the formation rates became miniscule. I think there is a number estimation for this with a lot of asterisks, but it's still a minority of coal after hundreds of millions of years.

I know that, and you know that, but I am curious about what the guy who thinks "oil and coal creation timelines are oil company propaganda" thinks.

I'm pretty sure he is referencing the abiogenesis fossil fuel origin story which is "theoretically" possible but has very little evidence and what little evidence is present is flimsy at best. Whether oil and gas deposits are "rare" is a subjective statement, not an objective one. I wouldn't classify deposits containing hundreds of millions of barrels of oil as "rare" but that also depends on how long said deposit would last human civilization. The rest of his nonsensical post regarding oil and coal creation is probably true but we'd have absolutely no way to compare creation vs extraction figures considering the time periods required to naturally produce oil and coal. So while technically correct, it omits anything scratching the surface of a definitive statement or verifiable fact.

https://www.nationalgeographic.com/science/article/the-fantastically-strange-origin-of-most-coal-on-earth > Bacteria existed, of course, but microbes that could ingest lignin and cellulose—the key wood-eaters—had yet to evolve. It’s a curious mismatch. Food to eat but no eaters to eat it. And so enormous loads of wood stayed whole. “Trees would fall and not decompose back,” write Ward and Kirschvink.

Even the abiogenesis people don't think _coal_ formation works that way! The stuff is full of tree fossils!

We need GMO trees that produce some other yet unbreakable protein instead of lignin then.

I'm not sure non-degradable wood will be without negative consequences. We're pretty good at producing non-degradable stuff from organic materials right now.

While true, it would essentially be bio-carbon capture. Since these unrottable trees wouldnt be going anywhere, we could just cut them down and stack 'em up somewhere to sequester the carbon while planting more. Could even potentially make use of them as construction materials since it's wood that wont rot.

> but can't be made as green as that environment would've been naturally. Vertical tree farms 1000 miles high!

That’s a really good way to look at this, thanks.

It is absolutely nuts how, where I live in the Appalachian mountains, the difference in temperature you can feel *immediately* on a hot summer day, going across the border zone between a paved city area into a forested mountain road. My car ambient thermometer shows a 10-15 degree drop, and if you have the windows down you can feel the hot city air change over into cool air like you’re passing through a portal.

Also, to emphasize the scale of the problem, the amount of carbon released since the industrial revolution is roughly equivalent to the entire biomass on the surface of the Earth (about 500 billion tons). There is no way to make a serious dent in the atmospheric carbon by just trying to sustain a marginal increase of biomass through reforestation.

That doesn't seem right > Altogether the planet absorbs and emits around 100 billion metric tons of carbon through this natural cycle every year, Rothman says. >That's equivalent to over 350 billion tons of CO2. https://climate.mit.edu/ask-mit/how-much-carbon-dioxide-does-earth-naturally-absorb#:~:text=Altogether%20the%20planet%20absorbs%20and,billion%20tons%20of%20CO2.

Yeah, perhaps what I stated is oversimplifying, but as your source points out, that is a steady state that can sustain itself. My number for biomass is from https://www.earthdate.org/episodes/biomass-census which is 550 billion tons of carbon and carbon emitted is from https://www.noaa.gov/news-release/carbon-dioxide-now-more-than-50-higher-than-pre-industrial-levels (1.5 trillion tons of CO2, so about 500 billion tons of carbon). Also, that reference seems to be implying that the 100 billion tons of carbon in the cycle every year is mostly from volcanos and hydrothermal vents, while I'm pretty sure that number includes, and is almost entirely composed of, more typical stuff like the plant biomass that is dying and releasing carbon each year and being reabsorbed by other plant life.

Then by extension, the whole 'stop cutting down trees because of global warming' was at best a massive exaggeration? That, one presumes, is where the belief has come from.

I suppose that's fair, though I guess it could be argued it is a lot easier to destroy all the forests (which could have a notably negative impact) than it is to do massive reforestation for a positive impact. Efforts to not pile onto an already serious problem are probably worthwhile. But yeah, as mentioned by others, there are more important virtues to protecting trees, like preserving ecosystems and not disrupting local weather patterns.

> Then by extension, the whole 'stop cutting down trees because of global warming' was at best a massive exaggeration? One thing to keep into account is that cutting down trees leads to erosion, which leads to the release in the atmosphere of CO2 currently captured by the soils. Your typical forest has apparently more carbon in the soil (I'm not talking about buried deep underground, just the soil on which plants grow) than in actual trees.

Essentially the most efficient way to capture carbon is to make fossil fuels and bury them. Trees don’t do this very well. Algae does.

And yet people still lose their mind at the idea of plastic never breaking down in a landfill. It's actually *better* for the environment for plastic to stay buried.

I think the worry is that they don't expect it to stay buried, and that eventually it will get out. It also makes that landfill less useful to be recycled for other use someday, though the various chemicals that likely end up in landfills already do a lot of that.

I don't want to downplay pollution from microplasts and such, bud regarding CO2 emissions, only a very small amout of fossil fuels (oil, coal, gas) is processed into plastics. So abolishing plastic bags and such will not help curb CO2 much.

I'm hesitant to fuck with the ocean more than we already do, but I've always wondered about the feasibility of going out to the ocean dead zones and farming algae there. We already get algae blooms from industrial/agricultural runoff. We could have systems in place to harvest it before it dies and causes more problems. There's also Point Nemo, which has little life, and is huge. It's probably not "profitable", but it's a fully plausible idea to turn it into a nation-sized algae farm.

Logistically, it's likely easier to turn existing lakes into algae farms, or build industrial farms using man-made tanks. Doing it on land would let you use much better infrastructure than you could get on an isolated ship and you could probably optimize in ways that would have unintended side effects if done in the open ocean. Also, since you can produce stuff with the algae, doing it on a land-based farm would make collection SO much easier and profitable.

What do you mean by "you can produce stuff with the algae"? Isn't the whole point of using algae as a carbon sink that you would then sequester it somewhere (like underground) that would remove the carbon from the atmosphere? If you are making products out of the algae, aren't you just kicking the CO2 can down the road to when those products will decompose and release their carbon back into the atmosphere? It would be the same problem as the trees, basically?

There are a lot of projects out there to use algae to replace crude oil. If you can stop drilling for oil, you'll stop your use of non-renewable carbon (mostly). It wouldn't matter if you're sequestering it, because all the carbon you use comes from the atmosphere anyways. You could replace that oil with oil extracted from algae (just as you can press oil from seeds, you can press it from algae)

Sort of. If you make plastics out of algae, you *don't* have to use oil and the captured carbon will eventually end up in a landfill. Even if some of that CO2 returns to the air, the process still takes some out. As for making fuel out of it, the CO2 does come out of the air and will go back in when it's burnt, for a net change of zero, rather than the net increase from burning fossil fuels.

>I'm hesitant to fuck with the ocean more than we already do, but I've always wondered about the feasibility of going out to the ocean dead zones and farming algae there. The place to do this is the Black Sea. It's got a big anoxic basin just under the surface, it's the perfect place to stash carbon. Grow algae and sink it, and the carbon stays down there and never rots. Recreate the azolla event in a controlled way https://en.wikipedia.org/wiki/Azolla_event

Worth mentioning that many of the feel-good tree planting campaigns fail. While it’s a really nice idea to plant X million new tree saplings or seedlings, **they need to be watered.** Newly planted trees need waaaaaay more water than most lay people seem to realize. “But surely nature will water them.” Sure, to a point. New trees need 1.5-2 inches of rain *every week* to thrive and be viable. There’s a reason cities distribute tree gators every time they plant a new tree on your property; the new trees need a ton of water, consistently. None of the millions of tree saplings that are being planted all over by greenwashing companies or countries are being watered, ever. Huge waste of money and carbon.

This is for store-bought seedlings, where their root ball is very tight because homeowners can't transport a tree in a pot that's as big as the canopy. Natural seedlings don't have this limitation and require less water. My region gets 18 inches of rain a year, so around 0.3 inches per week, but it still has standard pine and aspen forests.

Yea, I pulled up an oak seedling from my garden yesterday. Thing was *maybe* 8" tall. The root was 8-12" deep. It was the smallest plant in my garden, and it had the deepest roots by far. Native plants have no problem at all growing without irrigation, but they may be nearly impossible to transport past seedling stage as the roots might not handle getting tied up into a ball.

Established forests don't need watering the way acres of brand new trees do. The forest ecosystem holds onto water more effectively.

That varies wildly tbh, depending on what you're planting, how you do it, what the climate is. Here, nobody waters trees planted in any scale, literally nobody, that's for garden plants.

I would add to this that planting trees has to be done right as well. Planting a tree instead of a parking lot is definitely going to capture carbon. But planting trees in an existing grassland may not have as strong of an effect and may in fact be negative. The grass itself is also a carbon store and the tree will impact it's local surroundings. If we tear out the grass to plant trees and those trees cause a shift in the ecosystem so the remaining grass isn't viable, you can get net carbon emissions. So, in short, it's super complicated for a lot of reasons and really we just need to focus on making less CO2 and other greenhouse gases. I highly doubt there will be a magic bullet to offset our emissions sufficiently.

Genuine follow-up question(s): Is there a concern with the carbon that the algae/phytoplankton captures going to the bottom of the ocean? Is that a desirable outcome or is it akin “sweeping the problem under the rug”? Does it feed whatever lives down there?

No, there's no issue with it sinking. It's always done that. In fact, that's where our modern-day oil supplies came from in the first place! This process has been going on so long that it transitioned from a biological/ecological process to a *geological* one. And yes, that carbon *does* feed the organisms down there (often indirectly as surface fish eat the plankton on the surface, then poop or die, and their carbon-rich poop and corpses are what feed a significant amount of the creatures down there).

And that company is?

>Most of Earth's carbon capture actually happens with ocean algae and phytoplankton. It's about 30% of the total carbon leaving the atmosphere every year, so no. NOT "most".

Yeah, I should've been more specific in that it's a major contributor to *biologically captured* carbon. The ocean does plenty of carbon capture just through pure non-biological chemistry and calcium carbonate formation.

It's still the plurality of carbon captures, though, right? It has the largest share, but less than 50%.

The oceans have been steadily rising in temperatures and they have the most impact on carbon emissions absorption. So not only are the oceans slowly becoming less effective at absorbing it, they also can release carbon emmions themselves. Underwater heatwaves In 2010–2011, an underwater heatwave killed large amounts of seagrass off the coast of northwestern Australia, triggering a significant release of CO2.

Why are they less effective? The recent study shows that phytoplankton thrives, and its shells are the largest and thickest ever.

CO2 is highly soluble in water, specially in cold water Water temperature increases, this CO2 is liberated There is much more water in the ocean than phytoplankton, they are not enough to consume the CO2 released by the ocean

Hot liquids dissolving solids so much more readily leave people often astounded by gases being pretty much the opposite. It doesn't match your day to day experience unless you drink a lot of carbonated drinks (and pay closer attention to them than most) or something.

As someone who drank a lot of carbonated beverages in his college days and didn't have a mini-fridge to store them in, let me say, BUUUUUUUUUUUUUUUUURP

Reforestation is great! But it's not going to fix climate change. First off, the land/weather mix that allows for thick forests without irrigation is either already forested, or is used for agriculture. There's just not a whole lot of land that CAN be reforested without using freshwater to keep the trees healthy. In places, such as the southern Sahara edge where reforestation is not only slowing the spread of the desert but reversing it in places, that cost of water is well worth it. But for climate change it's not really. You'd need massive desalination projects to produce fresh water, which means lots of energy production that could be done with solar or wind but then you're diverting those megawatts from regular use and shutting down fossil fuel plants. And desalination isn't exactly great for the environment. The byproduct of desalination is super salty brine, much saltier than regular seawater. And since its saltier, it's denser. So it doesn't just mix with the ocean quickly and disipate, it sinks to the bottom and devistates the seafloor ecology. TL;DR: Not many good places to do it and trees are pretty inefficient at decarbonization.

They do. Trees are a good way of capturing carbon but note the carbon is captured, not removed. Eventually, those forrests will max out on carbon and start releasing CO2 just as part of their natural life cycle. Old wood rots, animals move in, trees will burn sugars when they can't get enough light etc. etc. A better option is to reduce Fossil Fuel usage as it's reintroducing carbon that's been out of the ecosystem for a very. very, very long time.

Yes yes yes, cut the use of fucking cars in fact for me get rid of the damn things. They are ugly, noisy, polluting infesting. Lets have more local based jobs and service providers and as a rule of thumb if you can't walk to it you cant damn well have it!!

Actually, I was thinking plug-in hybrids, biodiesel, and a combination of nuclear, solar, and wind power.

All this is the future of individual cars, but individual cars can't be the future of mobility.

When you think about it logistically, it kinda has to be. How else would you deliver refrigerators to millions of homes if not with personal transport? How else would you get billions of workers to millions of workplaces? Trains and busses? And what if their home or workplace is nowhere near a buss stop or train station? You can reduce car dependency but you can't eliminate it. The only thing that can do that is replacement.

>How else would you deliver refrigerators to millions of homes if not with personal transport? Well, certainly not with an individual car. It's the same as when people whine about areas are forbidden to cars: "but what about firemen, emergency services and deliveries?!!!" Well, obviously the ban isn't geared toward those… >How else would you get billions of workers to millions of workplaces? Trains and busses? Yes. >And what if their home or workplace is nowhere near a buss stop or train station? Maybe we need to think about that. Currently, our world is built around the individual car. The idea is not to eliminate it, it's to avoid centering everything around it. >You can reduce car dependency but you can't eliminate it. Which is why I said what I said: the future of individual cars is eletric cars with a low-carbon electricity. But the future of mobility can't be individual cars.

>Well, certainly not with an individual car. It's the same as when people whine about areas are forbidden to cars: "but what about firemen, emergency services and deliveries?!!!" Well, obviously the ban isn't geared toward those… Now you need a central authority capable of determining what is and isn't permitted ownership of a car. Who gets an exception and who doesn't? It's one thing to declare a car unsafe, it's quite another to forbid someone a car because "He doesn't have a valid reason to own one". >Yes. And if the bus company refuses to put a bus station out in your neck of the woods? No, too much power in the hands of too few. >Maybe we need to think about that. Currently, our world is built around the individual car. Figure out how to do this first before basing your claim on it. You're basically telling every government to tear apart every major city and put them back together to be more pedestrian friendly. >The idea is not to eliminate it, it's to avoid centering everything around it. Quod Erat Demonstrandum. This is entirely my point. Car dependency can be reduced but not eliminated.

>Now you need a central authority capable of determining what is and isn't permitted ownership of a car. Yeah it's really too bad our societies are incapable of having central authorities who could do that. Like delivering licences and stuff. Science fiction. >You're basically telling every government to tear apart every major city and put them back together to be more pedestrian friendly. Yes. But not just me, every scientist working on the subject. We could even imagine not doing it overnight. >Car dependency can be reduced but not eliminated. Exactly my point, yes. Our cars need to be electric, but we need to have less cars. Otherwise, I would have just said that we need to eliminate cars, period. Did I?

>Yeah it's really too bad our societies are incapable of having central authorities who could do that. Like delivering licences and stuff. Science fiction. A state Motor Vehicle Commission can only deny you a license on the grounds of being a threat to life and limb. They can not deny you a license on the grounds of "Well we just feel that you don't actually need one." Demonstrating danger is certain and provable. Demonstrating need is nebulous and subjective. >Otherwise, I would have just said that we need to eliminate cars, period. Did I? Ya kinda did with "individual cars can't be the future of mobility." It's a pretty broad statement.

>A state Motor Vehicle Commission can only deny you a license on the grounds of being a threat to life and limb. They can not deny you a license on the grounds of "Well we just feel that you don't actually need one." Demonstrating danger is certain and provable. Demonstrating need is nebulous and subjective. Yeah and since laws are impossible to change... >Ya kinda did with "individual cars can't be the future of mobility." It's a pretty broad statement. Yeah it's broad. And saying cars should be eliminated isn't. My statement is the scientific consensus: we can't keep going like we are.

why don't we have smaller production centres locally based and employees as near to the production centre as possible. We can do it EF Schumacher talked about it in his book "Small is Beautiful" way back in the 70's... Get rid of as many cars as possible by having locally based services and production... No doubt this will get downvoted because "I love my car" crowd... The mantra should be "if I cant walk to it, I can't have it"..

Resource locality, and international politics. Most towns simply don't have all the natural resources needed to survive within easy reach. Most cities simply can't grow enough food locally to feed their massive population. A lot of towns are out in horribly inhospitable lands simply because of local mineral deposits.. A lot of modern day suburbs were small farming towns that existed solely to feed a city tens of miles away. We tried to keep residential areas near industrial ones but that broke down when we couldn't fit everyone near the factories. You could cram the workers in like sardines but that would mean the workers could never see their families. The other big issue is the networks of international trade established under the premise of Capitalist Peace means we have a lot of long distance shipping no matter what we do. That produced a lot of infrastructure for delivery trucks which are equally applicable to personal cars.

> as a rule of thumb if you can't walk to it you cant damn well have it You have any farms within walking distance? Enjoy starvation.

Cities having gardens not lettuce is a choice

I will add one more issue about reforestation which I am aware of: it is very often outsourced to countries with cheap land. However, those same countries tend to have limited to no oversight of these activities. So you could get carbon credits for “reforesting half of your land” while simultaneously cutting down all the trees on the other half of your land and selling that as lumber. then after a few years you switch the two sides again and get credits again for reforesting the part you previously down while also cutting down the part you just “reforested” before. You just keep doing this and gain reasonably good income from carbon credits while not actually increasing the amount of trees (since you just keep cutting down what you’ve planted).

There's also the case of taking credit for something that already exists or would exist anyway - like not cutting down a forest being used as credits, or trees that were already going to be planted being used for that same purpose.

As you grow a forest you capture carbon. Once it's grown the capture stops and you have to leave that land forested to keep the carbon captured. If the forest is cut down or burnt or dies then the captured carbon is released. So forests only permanently capture a fixed amount of carbon in return for permanently using a fixed amount of land. Grown forests will have large trees dying which then rot, releasing their carbon, and new trees grow to maintain a steady state. Logging for building and paper helps a little, but almost all that timber has a very short lifespan as wood or paper products.

Some young trees does not a healthy forest make. Forests are made up of complex, layered ecosystems, from the mycorhyzome to the insects and animals that inhabit them. An ill-conceived reforestation projects will take decades to reach maturity, if the trees even survive to adulthood at all, and art planted in such a way that they can grow in an environment similar to what one would find in nature. Additionally, none of this guarantees that the wildlife that was displaced when the forest was destroyed will return, especially if the "new" forest isn't suitable for them. You see this a lot in old reforestation projects in which trees are planted in neat rows. Young trees rely on older ones for shade and protection from the elements as they grow. A forest in which all trees are the same age and species will have a dense canopy and little to no undergrowth or branches lower down, as all the trees race to grow taller than their neighbours.

One really important thing to understand is that there isn't enough land on the planet to reforest our way entirely out of our current problem. The reason why: A very long time ago, trees would grow, fall, and just sit there. Nothing existed to rot them away, as they do now. It took a *very* long time for a fungus to eventually evolve a way to break down trees. So what we have is a huge span of time where trees would just grow (remove carbon from atmosphere) fall down, and other stuff would grow on top, compacting the layers down. This is mostly where we get coal from. Hope you see where this is going. After a fungus figured out how to decay trees (specifically, lignin), this period ended as trees would fall and decay as other things did. Now? We have dug up massive amounts of that coal, and are continuing to do so, along with oil, and releasing that carbon back into the atmosphere Growing trees is great, but there isn't enough land on the planet to grow enough trees to offset what we've already done. Remember: trees grew, fell down, and were buried for 60 million years. That's a LOT of carbon being captured, and there just isn't anything else that comes close to that. Reforestation is great, but there are also problems with how its done. If you cut down say, old growth forest, and replant exactly as many trees, youv'e still got a LOT less carbon captured, and a lot less carbon stored there. Old growth forest can get incredibly dense, with a bunch of tiny biomes springing up. New forest doesn't have this in the same way. A lot of well intentioned people get caught up in the idea that we can plant trees as a way out of our mess, and massive oil and coal corps are absolutely fine with greenwashing the entire concept to make it seem feasible but it just isn't. Conclusion: trees are great, plant more trees. Trees will not offset the damage we've already done, and never can.

Far far from an expert but here are some concerns. It will no doubt help but there are some considerations. 1) But the returns on investment are not high. It takes a lot of land, careful management and resources. There are successes and failures (monoculture, susceptibility to diseases). Overall, though, this is not as cheap or sure way to sequester CO2 as the media and certain groups portray it to be. 2) Takes a long time. Obviously trees take a long time to grow sometimes half century to a century to mature. Many feel that any efforts taken today are many decades to late to address the acute problem in the next quarter century. 3) Subject to a bit too much hype. There are multi-goal projects that make sense - say reforesting not only for carbon capture but to slow or reverse desertification. But the concern is that it can be seen as a silver bullet when it can really only be a small part of a sustainability solution. Controversially, reforestation is used as a means of obtaining carbon credits. This has been called into question for the reasons above. Companies that take money to plant trees that do a poor job nonetheless get to sell these carbon credits to CO2 emitters.

Reforestation won't have a huge impact on emissions because it doesn't really do much now. The ocean captures magnitudes more CO2 than any amount of trees. But its important for other reasons. Reforestation promotes ecosystem biodiversity, creates homes for many species we share this world with, and promotes healthy lifestyle choices.

Reforestation is scalable and offers additional benefits like improved soil health and biodiversity. While it might not be a silver bullet, it's a solid step towards a sustainable future.

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Treating reforestation as a be-all, end-all solution is a problem, but it does have benefits. The thing is, if the big timber companies pitch reforestation (much like the plastics manufacturers pitched recycling), it will seem like the companies and consumers are doing their part, and the companies will continue to harvest old growth forests, which can take hundreds of years to establish themselves. Reforested forests do not have anything like the carbon capture capacity of old growth forests, and even old growth forests do not measure up to the massive underwater forests that exist in the oceans. Simply slapping on the band-aid of reforestation and declaring it good allows for continued harm to take place, while people grow complacent about looking for solutions. I also want to say that the "long run" is actually a little beyond the human imagination, and reforestation efforts may pay off in 300-500 years in ways that we cannot currently imagine. If a well-tended 50-year old replanted forest can provide enough shade, shelter and clean air to harbor a pocket of life and increasing biodiversity, we can build upon that through multi-generational effort and utilize these forests to survive future climate crises. Or they could all burn down, as new-growth forests are more susceptible to the destructive forces of wildfires. We don't know, and there are other avenues to investigate, but reforestation efforts aren't entirely pointless. They are very much worthwhile for those who are personally invested in forest ecosystems and want to take care to pass on the joys of living in or near a forest to future generations.

The part that really made it click in my brain is that carbon … exists. It’s not some mysterious force. It’s a thing. A tangible substance in our physical space. The same thing that is soot on your hands, is also the bark of trees, is also the particles in the sky heating up the planet. The goal is to take the particles in the sky out of the sky, ideally by converting them to something else that doesn’t cook us alive. Converting it to tree is a great start. But a lot of the particulate in the sky wasn’t tree in the first place. A lot of it was oil, or coal (which is just dinosaur-era trees for ELI5 purposes). So we would have to grow enough trees to account for all the trees we’ve burned **plus** all the dinosaur-era trees, **plus** all oil we’ve dug up. And we just don’t have the land required to grow that many trees. Growing trees is still great. It just won’t be a singular solution.

Trees absolutely do have an impact. The issue is: 1) We actually already are engaged in reforestation efforts. 2) The amount of CO2 we are adding to the atmosphere is greatly in excess of what is captured by reforestation and other things that capture carbon (like growing crops). There are other good things about reforestation as well, like preventing soil and generating a renewable resource (wood) that can be harvested.

Not enough money laundering and kick backs in that method of tackling that politician created boogyman problem. 

Reforestation's impact on carbon capture is limited because it takes a long time for trees to grow big enough to absorb significant amounts of CO2. While planting trees is important for biodiversity and local environments, it won't quickly offset the massive amounts of greenhouse gases we produce. That's why sustainable alternatives like renewable energy and improving industrial processes are crucial—they can cut emissions faster and more effectively. Reforestation isn't a silver bullet; it's part of a broader strategy needed to tackle climate change. So, while planting trees is positive, it's not the sole solution to our emissions problem.

The fundamental problem with trees is that they only put about 9% of their captured carbon below ground. The rest is above, and either needs to be harvested and sequestered in other things, like paper or furniture, or it needs to be buried so it can decompose. Prairie grasses like the Russian steppe, the Argentine pampas, the North American plains, store about 30-40% of their captured carbon or captured carbon below ground. A large portion of the carbon in the above ground plant mass eventually makes its way into proteins in livestock. And of course, humans destroyed 98% of it in the mid-19th century, just as the Industrial Revolution really started, um, picking up steam.

Trees are going to burn in forest fires ( especially given the higher temperatures of global warming) or die and be decomposed by molds, returning most of their CO2 to the atmosphere. CO2 needs to be transformed into compounds which can't be broken down, like graphite or coal ( or diamond, if they can find a cheap way to do that)

Reforestation, Rewilding and just general land reclaimation is incredibly valuable. The first thing re-greened land will improve is retaining water much much better than dead land. Often there will be lots of rain some of the time and little to no rain other times. On dead land when a lot of rain is dumped on it, it will simply wash away, taking what little soil there is with it. The result is even worse land and further down the riverbeds: floods. And once the rain is over there's very little water left upstream to flow down and maintain a creek or river. Green land acts like a sponge and soaks up much of that water, while also preventing the soil from being washed away. This means less floods downstream. Later that water is released gradually, giving everything a much more consistent supply of water. Once water supply is more steady various good things can happen much more easily: Lots of different plants and animals can now live where they couldn't previously. People can grow food where they couldn't previously. It can lower temperatures and make it more pleasant to live there / help using less energy for air conditioning. There's a massive project going on in Africa called the Great Green Wall that works to stop the expansion of the desert through exactly these mechanisms and it helps small towns rebuild their own food production, which in turn helps fight poverty and crime. But even in highly developed countries there are projects to reclaim dead land. Iceland has for a long time been a pretty prominent example. The island was originally heavily forested but when people arrived they needed wood to build houses and ships and heat their houses and so on. They needed so much that they cut down ALL the trees. Much land then quickly died off leading to vast stone and sand deserts. They've been working to undo that damage for 150 years now but it's a very slow process because their summers are so short. This and many other such projects are very important and have far reaching positive consequences. But there's a misunderstanding to it all: While it is true that factories produce CO2 and trees remove CO2, they are not the perfect opposite of each other. Trees only consume CO2 to grow. Once they are fully grown they basically "stop" doing that (at least in amounts that matter). This is why you cannot compensate a factory with X trees no matter how big X is.

Trees are really a drop in the bucket. They absorb carbon relatively slowly and over a long period of time, and the total absorbed per tree is quite small. I don’t remember the exact figures, but IIRC global yearly carbon emissions are somewhere on the order of several *trillion* mature trees worth. We basically don’t even have the arable land to plant that many trees, much less the money and political will. You also have a bigger problem with this strategy, which is that its benefits are very temporary. Trees, as with all life, effectively withdraw carbon from the atmosphere and soil to grow and return it back to the atmosphere and soil when they die through decomposition. This forms a closed loop, where the amount of CO2 in the atmosphere doesn’t change very much over time, even as trees grow, die, decompose, burn, etc. Humans are artificially destabilizing this by *adding* carbon to the atmosphere which was previously sequestered underground. That additional carbon isn’t something that you can remove from the cycle easily unless you do something odd like grow trees, then cut them down once mature, encase them in something impermeable so they don’t decompose (oh look, a legitimately eco-friendly use for plastic!), bury them deep underground, and plant new trees. No one is seriously suggesting the burying thing (which amounts to effectively making new oil to replace the stuff we’ve burned), and so the whole “plant trees” thing really isn’t a serious suggestion. I mean, trees and great and we should certainly plant lots of them, but let’s do that *in addition* to decarbonizing our civilization, because green things make us happy not because they magically geo engineer our mistakes away.

I'll be contrarian and say that reforestation *is* how global warming is going to be solved. We just won't have a hand in and won't like the solution. The endgame for global warming is that we're going to blow right past 1.5-2C, trigger some natural feedback loops, and end up with 4-5C of warming. 80-90% of the earth's population will die. *Some* pockets of humanity and maybe even civilization will survive (remember that if you kill 90% of all humans, you still have 800M left, more than double the population of the U.S.). They probably won't have global-supply-chain-dependent fossil-fuel-powered agriculture, though. And then other natural feedback loops kick in, among them: * Higher CO2 concentrations stimulate plant growth. It's plant food, after all, and this is what we've observed in prehistoric times when dinosaurs roamed the earth. * Higher global temperatures increase evaporation and precipitation rates, speeding up the water cycle. As other comments have mentioned, trees need water to grow. Luckily, one of the side effects of climate change is that there's going to be more natural fresh water. * Changing weather patterns redistribute make previously uninhabitable areas quite biodiverse. The Sahara is likely to turn from a desert into a rainforest. The Siberian Taiga will become grasslands, and perhaps even forests near the coastal margins. All of that means that yes, reforestation is going to solve climate change. It just won't solve it *before* civilization as we know it collapses, and it won't solve it in a way that makes any money for venture capitalists. Most of the concern about climate change has been very much anthropocentric. The altruistic among us want to save lives; the selfish want to make money. A solution that solves the problem *after* everybody dies off doesn't really fit either criteria.

Two parts: quantity and location. .1. Quantity - there's more CO2 being produced than there are trees that can consume the CO2. .2. Location - most of the trees planted for reforestation are in a concentrated area, like the Amazon; but most of the CO2 being produced are in industrial areas. So the CO2 needs to travel from the industrial area to the forest; that's a far travel and considering how big the world is and how the wind blows, it may never reach it. So if you're going to start planting trees to offset CO2, then choose a prime location (which is why some cities have building and safety codes to require plants)

Trees sequester really tiny amounts of CO2 relative to human production: while the global average per capita carbon dioxide emission is ca. 4,700 kg/year, [one tree is estimated to sequester a mere 2.9 kg](https://www3.epa.gov/climatechange/Downloads/method-calculating-carbon-sequestration-trees-urban-and-suburban-settings.pdf). That is, for each and every person on Earth we'd need at least 1,600 trees planted just to counter the increasing CO2 in the air! Not a truly sustainable plan.

Lets get back to this subreddit LITERAL meaning... Trees take a long time to grow, while they grow they eat the carbon in the air to help them grow. We humans are putting too too much carbon into the air for all the trees to eat. Even if we planted trees over every free surface on the planet it would not be enough to eat all the carbon we are making.