The global tree restoration potential
July 7, 2019 12:21 AM   Subscribe

Tree planting 'has mind-blowing potential' to tackle climate crisis - "Research shows a trillion trees could be planted to capture huge amount of carbon dioxide."[1,2]

The potential for global forest cover - "The restoration of forested land at a global scale could help capture atmospheric carbon and mitigate climate change... Ecosystems could support an additional 0.9 billion hectares of continuous forest. This would represent a greater than 25% increase in forested area, including more than 500 billion trees and more than 200 gigatonnes of additional carbon at maturity. Such a change has the potential to cut the atmospheric carbon pool by about 25%."
The restoration of trees remains among the most effective strategies for climate change mitigation. We mapped the global potential tree coverage to show that 4.4 billion hectares of canopy cover could exist under the current climate. Excluding existing trees and agricultural and urban areas, we found that there is room for an extra 0.9 billion hectares of canopy cover, which could store 205 gigatonnes of carbon in areas that would naturally support woodlands and forests. This highlights global tree restoration as our most effective climate change solution to date. However, climate change will alter this potential tree coverage. We estimate that if we cannot deviate from the current trajectory, the global potential canopy cover may shrink by ~223 million hectares by 2050, with the vast majority of losses occurring in the tropics. Our results highlight the opportunity of climate change mitigation through global tree restoration but also the urgent need for action.
This Easy Climate Fix Has More Potential Than Previously Thought - "A new analysis finds nations could be growing forests where they aren't, removing millions of tons of carbon from the atmosphere."
posted by kliuless (66 comments total) 56 users marked this as a favorite
This is exciting! Thank you for posting it.

If, like me, you now feel like donating money to plant some trees, here's a list of tree-planting organizations.

Also, shoutout to a search engine called Ecosia which gives 80% of its profits to world reforestation efforts. I downloaded the Ecosia browser extension a couple of weeks ago and give it two thumbs up.
posted by hungrytiger at 1:37 AM on July 7, 2019 [18 favorites]

If, like me, you now feel like donating money to plant some trees

I feel much less powerless at the idea that I can make a positive impact by throwing some money at some folks to plant some trees vs trying to change global politics, so this was indeed my first impulse. Thanks for the resources, hungrytiger!
posted by terretu at 1:54 AM on July 7, 2019 [3 favorites]

Yeah, sure, and I plant plenty of trees myself, but that article is the classic top-down, view from orbit, tech-bro "hey let's do a thing, it'll be easy" kind of solution that's literally disconnected from the reality on the ground.

There's a heap of benefits to trees, so why is the world cutting down about 18 million acres of forest year on year? Because the net benefits that cutting down trees bring are more highly valued by decision-makers than the net benefits of leaving the forests or replanting. Most deforestation comes from farming, grazing, mining, illegal logging, and urban expansion. Planting more trees won't happen at scale unless you solve each of those specific problems in each specific location. The solutions might involve property rights, or enforcement of existing laws, or payments for ecosystem services, or correctly pricing externalities, or etc etc but those solutions will be local.

I'm in NZ, we've down to 30% forestry cover, from pretty close to 100% not too many hundred years ago. We're not replanting on mass because of a piss-poor carbon price and a growing and protected dairy sector. The solution for us would be to restructure our largest dairy company into an entity that pays its full cost of capital. That has only an indirect link to forestry, but would result in massive reforestation and carbon uptake. It's also not a solution to anyone else's problem but ours.

Trees are local, so please can we have local solutions that engage with reality?

No, it's ok, only kidding. What we need is Uber but for drones that plant trees, using the blockchain and 3D printing. Then we IPO, cash out, and plant trees on Mars.
posted by happyinmotion at 2:37 AM on July 7, 2019 [80 favorites]

happyinmotion: "What we need is Uber but for drones that plant trees, using the blockchain and 3D printing. Then we IPO, cash out, and plant trees on Mars"

posted by chavenet at 2:46 AM on July 7, 2019 [71 favorites]

Yeah, sure

No, not "sure" at all. We've literally just been told that our projections about the likely impact of tree planting were massively inaccurate, and that tree planting may be the primary tool in giving us a shot at an Earth which is habitable for humanity in the 22nd century. This is new information that it's really important for people to understand.

Trees are local, so please can we have local solutions that engage with reality?

Yes, we can, but the whole point of the analysis being discussed is the global impact of tree planting on an unprecedented global scale. The issue now is to move this activity up the agenda everywhere, taking advantage of the idea that this is something we can actually do to give our great-grandchildren a reasonable chance at survival. I agree with you, absolutely, that the work needs to be dealt with on a local level, over and over again, but that doesn't mean that global analysis of our global problem isn't essential and relevant.
posted by howfar at 3:35 AM on July 7, 2019 [38 favorites]

Kevin Drum addressed this a few days ago:
Once the trees were grown, they’d capture about 205 gigatonnes of carbon. That sounds great, but let’s give it some context:

We have emitted about 450 gigatonnes of carbon since the start of the Industrial Revolution. At our current rate, we’ll add another 205 gigatonnes in less than 20 years.

If we could really get all the countries of the world to plant trees on currently unused land that’s suitable for reforestation, that would be great. But even if we went all out and got 100 percent cooperation, it would take 50 or 60 years for these forests to grow to maturity. Unless we do something about actual emissions, we will have added at least 500 gigatonnes of additional carbon by then, bringing us to total emissions of about a billion gigatonnes of carbon. The trees would make only a small difference.
Drum frequently points out that doing anything significant about anthropogenic global warming will require large cuts in carbon emmissions that apparently Americans aren't even willing to consider -- the reality of the scope of necessary lifestyle changes is so great that everyone avoids discussing it and instead talk about changes at the margins. Even planting 500 billion trees is woefully insufficient.

I'm not quite as averse to geoengineering remediation as many people are, but such proposals seem to share a certain "cake and eat it, too" implication.
posted by Ivan Fyodorovich at 4:05 AM on July 7, 2019 [20 favorites]

Would it make sense to coppice or harvest these trees when they're fully grown so that we can grow replacements for them and sequester more carbon?
posted by Joe in Australia at 4:06 AM on July 7, 2019 [1 favorite]

If this is important to you, I suggest you contact your local municipality and ask them to allocate land for planting trees within municipality limits. They are likely to be willing to do this as there will be many strips of land too small to build on that could provide a home for these trees, and it will look good on them at negligible cost without annoying the corporations that contributed to electing the counselors. Trees bring up the property values, so that will also be incentive.

If the trees are planted in populated areas this means there will be people observing who can help keep them alive. If you get a small local group planting trees it will encourage other people to get involved in the initiative, which will be much more possible if it is local, as opposed to say, planting trees in a rural area in Nevada. The ideal would be to work towards getting a local group organized which is aiming to plant and keep alive one tree for every person in the municipality.

Planting trees, unlike not using plastic drinking straws, is something that anyone and everyone can do that could actually make a difference.
posted by Jane the Brown at 4:06 AM on July 7, 2019 [17 favorites]

tree planting may be the primary tool in giving us a shot at an Earth which is habitable

That's not a new conclusion at all and the supposedly authoritative evaluation of where trees could be planted looks not much better than what's been done regionally for at least the last ten years. It's not like NZ's a leader in GIS but we've had that info available since at least that long.

If I go to their maps and zoom in on the city I live in, they're suggesting we could plant trees on the airport runway. That's the third-busiest runway in the country. Ok, tearing it up would certainly reduce the overall carbon emissions, but ffs, that's exactly what I'm criticising them for - it's a top-down analysis that ignores the local factors that determine whether their solution is at all possible - like the alternative uses of that land and the value of those uses.
posted by happyinmotion at 4:07 AM on July 7, 2019 [3 favorites]

Would it make sense to coppice or harvest these trees when they're fully grown so that we can grow replacements for them and sequester more carbon?

posted by Joe in Australia

Only at the end of their natural lifespans. While they are alive trees remove carbon from the air. You want as many mature trees in the system as possible, as replacement saplings are not large enough to do much of the work.

It is worth debating between growing small, short-lived fast-growing fruit trees which remove pollution from the air more efficiently than non-fruiting species, than to plant slower growing hardwoods which remove much more carbon once they are grown, but the main things is to plant trees, any trees, all trees, everywhere.
posted by Jane the Brown at 4:12 AM on July 7, 2019 [5 favorites]

If you look at the global CO2 charts on a monthly or shorter scale you see the seasonal variations which are significant and driven by plant growth. So yes planting things will absorb CO2 and a lot of it.

But you have to keep it sequestered in dry products, not decomposing. Stuff has to be harvested and kept aside. Not burned or eaten. Same thing.

Drones with fast growing grasses like hemp plus slow growing trees together could make an impact.
posted by seanmpuckett at 4:13 AM on July 7, 2019 [2 favorites]

In the UK the argument for giving up on hill farms and allowing reforestation now seems even stronger - though George Monbiot has been pressing it for years. We could present it as reversing the Highland clearances!
posted by Segundus at 4:13 AM on July 7, 2019 [6 favorites]

I don't see anyone here arguing that we should only plant trees and do nothing else, so it's a little weird to see folks coming into this thread to kick the stuffing out of that particular strawman.

Why wouldn't we want to harness every possible tool to combat climate change?
posted by duffell at 4:25 AM on July 7, 2019 [39 favorites]

That's not a new conclusion at all and the supposedly authoritative evaluation of where trees could be planted looks not much better than what's been done regionally for at least the last ten years.

So, you're saying it's somewhat better than the regional analyses and exists on a global scale? That seems like a pretty strong justification for the analysis, if you ask me.

Honestly, you seem to be angry about something which helps us because it's not something which helps us in a different way. I know these are difficult times, and every news story seems like a looming disaster, but you seem to be attacking something that is actually quite useful.
posted by howfar at 4:28 AM on July 7, 2019 [4 favorites]

About 155 trees per person. Cost somewhere between $0.10 and $20 per tree. Each hectare has enough space for about 16 people's trees. That would get us started - but there also needs to be some ongoing cost centred around providing an economic incentive to plant and maintain the trees - maybe a maintenance cost of 10% of the original?

Tree planting is not a new solution to global warming - but it does have the advantage of being a solution which is both effective and easy to communicate.
posted by rongorongo at 4:32 AM on July 7, 2019 [2 favorites]

One other thing that's worth keeping in your pocket that I found personally useful is keeping up with the efforts to do biodiversity financing, which deals with conservation on capitalist terms for sure, but expending energy to develop schema for the economic valuation of trees can be a very compelling argument for policy makers, since tree cutting and logging etc do make their typical calculations on 'free' 'economically inactive' resources. Financing mechanism like this is at least trying to quantify the economic cost
posted by cendawanita at 4:39 AM on July 7, 2019 [4 favorites]

I'm in NZ, we've down to 30% forestry cover, from pretty close to 100% not too many hundred years ago. We're not replanting on mass because of a piss-poor carbon price and a growing and protected dairy sector.

There's definitely a consumer based bottom up way to make life difficult for the dairy and beef industries, which is to stop buying dairy and beef. You can also be bright and positive and non judgemental when the subject comes up and say that that's what you've done. A plant based diet is not a real hardship in the industrialised world, and it's practically impossible for a normal plant based diet to have greater impact than an animal based one.

Of course, government action's needed in order to change the priorities for that land, which is why I'm suggesting that you do talk about pasture being a huge waste of land. I know it's now received woke wisdom that actually pasture is good because it's not useful arable land, but the issue here is that it is good woodland.

And because people won't read The Guardian article, I'll summarise the easy bits:
  • 1.7bn hectares of undeveloped deforested land unused for farming globally
  • It would cost $300 billion to plant 1 trillion trees
  • It could sequester ⅔ of human CO₂ so far emitted.
  • It wouldn't interfere at all with other decarbonisation efforts
There is nothing to be negative about in this. The scale is feasible, no megaprojects needed, just a steady global effort.
posted by ambrosen at 4:44 AM on July 7, 2019 [25 favorites]

Trees are great and should be everywhere -- most parking lots and highway medians should be trees, and planting trees should be part of a national service requirement -- but we should be careful not to present planting more trees as the sort of "hey, this is all we need to do to save the planet!" scheme that people get behind to avoid inconvenient change. Planting more trees is one tool. Causing less deforestation is a more important tool. Don't eat imported food (or ingredients) and don't eat animals.
posted by pracowity at 4:53 AM on July 7, 2019 [9 favorites]

I agree that it's important to keep reiterating that this is a medium term tool, and that, if we don't act now to halt and reverse emissions growth, much of the land currently identified as useable will be desert before the trees have a chance to make a blind bit of difference to anything.

It's good to have this analysis being presented so publicly, but I think it primarily needs to be used to counteract the "we're all doomed long-term anyway" defeatism that can lead to paralysis. I think it might be best framed as "trees are an investment in the future: planting them is a commitment to protecting them for our descendants". It hints at a vision of a world surviving climate change by changing itself for the better, by making its citizens happier and its habitats more stable. That seems a great fucking story to inspire people with, but that sort of inspiration without proper direction (or with improper direction, which is a massive fear that in our world) is, as you point out, pracowity, potentially very dangerous given the limited time and power (politically speaking) we have to act.
posted by howfar at 5:15 AM on July 7, 2019 [7 favorites]

Don't eat imported food (or ingredients)

Don't eat unnecessarily imported food is probably good advice, and you're lucky enough to be writing it from a country with spectacularly good local produce. But e.g. I'm 200 miles too far north for chestnuts to grow. If we start reforesting and a good portion of that previously wasted land in France goes on chestnut trees (a very productive northern European woodland food, no longer cropped in large quantities), I should buy chestnut flour in preference to a field grown flour, right?
posted by ambrosen at 5:15 AM on July 7, 2019 [1 favorite]

A simple rule like don't eat imported food, like don't kill people, obviously needs lots of tweaks and exceptions in actual practice, but the general rule is sound. Don't eat food grown far away when you can buy food grown nearby, especially when buying food grown far away encourages people to cut down forests to feed you.
posted by pracowity at 5:34 AM on July 7, 2019 [2 favorites]

Coincidentally, I saw this yesterday which reckons the most effective thing we can do to reduce carbon emissions in the near future is to stop shutting down existing nuclear power plants before their time. Which isn't quite as appealing as planting lots of trees.

(I wouldn't be surprised if various assertions in it are dubious-to-complete-bollocks though)
posted by grahamparks at 5:49 AM on July 7, 2019 [2 favorites]

About 155 trees per person.
Can't I just plant some Sargasso?

This is going to take government action. Paying farmers to plant trees. Farmers control a lot more land than is in cities. We pay for corn ethanol, why not trees? It has to be one of the cheaper possibilities.
posted by Bee'sWing at 5:50 AM on July 7, 2019

I'm in NZ, we've down to 30% forestry cover, from pretty close to 100% not too many hundred years ago.

As a point of comparison, early in the Industrial Revolution, New England was down to about 20% forest cover. This was due to clearing for farms, burning wood for fuel, and the other uses we put wood to. Starting around 1850, agriculture moved to the Midwest, and now the area is largely reforested. If you look at contemporary paintings of the route the British troops took to Concord on April 19th, 1775, there are almost no trees. Today, that "Battle Road" is heavily forested.

Don't eat food grown far away when you can buy food grown nearby, especially when buying food grown far away encourages people to cut down forests to feed you.

Unfortunately, buying food grown locally also encourages people to cut down forests to feed you. It might be better to import food from a place unfriendly to trees.

...stop shutting down existing nuclear power plants before their time.

I don't think this has been happening. Power companies have been actively demanding license extensions far beyond the designed life of their nuclear plants, sometimes with bad consequences.
posted by Kirth Gerson at 5:54 AM on July 7, 2019 [4 favorites]

There's a line in the new Richard Powers book The Overstory that deforestation has caused 4x the carbon emissions of all transportation. I had a minute fantasizing about a story where some country's supermilitary reforested the world by force—destroying nearly all communities and forcing them to adapt to live in forests that were policed and couldn't be cut. I guess it feels like that's what it would take.
posted by little onion at 6:11 AM on July 7, 2019 [2 favorites]

Nuclear power shutdowns.
posted by Bee'sWing at 6:12 AM on July 7, 2019 [1 favorite]

I'm in no way opposed to tree planting (actually, I've been responsible for having many tens of thousands of trees planted over the past decade), but the maps that were linked to above could use some fine-tuning. I looked at an area I know well, and they show highest "forest restoration potential" across some of the most productive farmland in the country (as well as being land that was historically grassland, not forest).

I'm willing to buy their overall analysis, but the details could still use some assistance.
posted by Dip Flash at 6:16 AM on July 7, 2019 [1 favorite]

Burn, by James Patrick Kelly is a thoroughly complex exploration of a far-future planetary society that seeded genetically-engineered trees to convert a grubby industrial colony planet into lush forests. The whole world is named Walden and is under a sort of "simplicity decree" not unlike the rules in many Mennonite communities in the US.

It did a pretty good job of presenting what we'd think of as a simple and obvious approach into a complex situation that has effects on personal relationships as well as international ones. I listened to it in 2004 or so when JPK had a very early podcast where he was going through most of his short stories, and he eventually did some of his novella-length work as well.
posted by rum-soaked space hobo at 6:25 AM on July 7, 2019 [2 favorites]

I saw this article and thought of posting it, but also thought I needed more information.
Reforesting is one of my big interests, and my interest has grown the last year or so after I learnt that the Bronze Age collapse may have encompassed a far larger part of the world, and also may be partly be a man made disaster (I'm looking for research to post here, I only heard it in a radio documentary and forgot to jot down the names). I'm also doing some thinking on my own, based on that, and to me it makes sense that in a world where timber and wool are the prime commodities, desertification is almost bound to happen. And that leads to famine and unrest.

This is not about the Bronze Age collapse, but about a theory that the Sahara was largely created by human mis-management 8.000 years ago. It's a contested theory, but one that matches my own experience from living in an area that was once desert. That was exactly how "my" desert came to be. My own experience also tells me that can be changed. Desert can become forest, and happily it's much easier than we thought just 30 years ago, from a biological point of view. The hard parts are the politics and the economy of it, and they are really hard.

I agree with happyinmotion that the way this is presented, like one of those "one simple trick" ads, is deceptive. But I can also see, just in this thread, how helpful it is to put out something we can all do.
Greening in cities and suburbs is often easier than to convert farmland, so go out and make yourself a forest garden, or get your municipality to develop a local square into one. It can be fun and pretty, and it's great for insects and birds and flood management.
posted by mumimor at 6:44 AM on July 7, 2019 [4 favorites]

There is nothing to be negative about in this.

Recycling gave a lot of people the sense that our problems with plastic were taken care of. I worry that that's exactly what will happen with this. Many people will believe all we need to do is plant some trees and the problem will be fixed.

I read this article earlier, and I believe it also said that it will only reduce 3/4 of the carbon in the atmosphere in something like a hundred years after the trees are planted, and planting is an enormous job. Don't get me wrong, I think we should be planting trees, but we need to move faster if we're going to avoid what might be an irreversible climate disaster.

Many people think they can wait to see some of the results of global warming and then we can start to pull back and implement solutions. The truth is that if we warm the atmosphere another degree and a half, the permafrost in the arctic then melts, and then massive amounts of carbon capturing chemicals are released. This in turn may cause a spiral of carbon releasing events the world will never recover from.

Many of these future scenarios are extinction level events, or similar enough that there's no appreciable difference. Most scenarios, for instance, conclude there will be less oxygen in the air resulting in diminished cognitive capacity no matter where you live. Most scenarios suggest that food will be hard to grow on any kind of mass scale.

So, trees are needed, and this is good news, but trees alone won't solve the problem.
posted by xammerboy at 6:56 AM on July 7, 2019 [4 favorites]

I'd love for there to be urban forests (mostly for the pleasure of them but also for urban heatsink prevention and wildlife habitat restoration) but the reason there are not are deep rooted socio-political problems. People in cities are very afraid of forests and the people who may choose to live and hide in them (crimers! poors!). In Chicago (whose motto is urbs in horto - City in a Garden) the only real forest near me is a small fenced off and padlocked bird sanctuary. Most of the rest of the massive lakefront park is English landscape (Capability Brown) garden style with individual trees well apart from each other on wide open mowed lawns that have pitifully small amounts of shade. It is less a park to be enjoyed than a park to be looked at as you drive, cycle or run by. It's actually more pleasant to walk along Chicago's heavily treed boulevard streets than through most of the city's parks.
posted by srboisvert at 7:00 AM on July 7, 2019

If you're interested in this kind of thing, the book The Planet Remade: How Geoengineering Could Change the World is worth a read. It talks a lot about various kinds of options for removing and/or coping with excess CO2. One big point it makes is that there's no need for any one solution to be complete. We can do several things at once: reduce emissions, plant trees, etc. It's also useful to simply slow global warming, even if we don't stop it entirely. Anything helps.

There's a whole chapter on planting trees. The biggest problem after labor is accessible land, it takes a lot of land to have enough trees to make a difference. That's what this whole paper is about, so I don't have much to add on top of its numbers. The book also talks about a few reforestation experiments, none of which have gone very well. Particularly a big effort in Western China where the actual result is something like 1/10 of what was expected. Not saying it's impossible, but there's hidden challenges.
posted by Nelson at 7:09 AM on July 7, 2019 [4 favorites]

I work on an army base. The base is sincerely trying to be ecologically sound, and pays a competent person as landscape architect. A few years ago the base decided to reforest a wetland area that used to be an artificial rice paddy (where they practiced spraying herbicides to efficiently kill rice and starve populations of people who eat rice). So they bought a bunch of [very nice] native species of trees and planted them. The species were planted in serial order, in straight rows, apparently with no regard to which species needed shade, which grew in clumps, and which tolerated greater wetness. It hasn't gone well. The landscaper has no employees and no budget and relies on volunteers. So although I am supportive of planting trees, I would foresee a lot of acres of dead trees unless a great deal of thought is put into actual implementation.

PS - We have thousands of milkweed plants on fallow ground here on base, right now with millions of monarch butterfly eggs on them. About the time the caterpillars have hatched, the army will mow down those fields to keep them neat.
posted by acrasis at 7:13 AM on July 7, 2019 [8 favorites]

There is nothing to be negative about in this. The scale is feasible, no megaprojects needed, just a steady global effort.

which is why it'll never happen; because silicon valley vampires can't get rich off it and slap their name on the side of some sexy technology like a rocket

No, it's ok, only kidding. What we need is Uber but for drones that plant trees, using the blockchain and 3D printing. Then we IPO, cash out, and plant trees on Mars.

now you're talking
posted by entropicamericana at 7:14 AM on July 7, 2019 [2 favorites]

It might be better to import food from a place unfriendly to trees.

There may be such cases. Rules have exceptions. But when you import your food from far you cause lots of extra pollution and you have much less control over deforestation. When your food comes from your state, less packaging, shipping, and refrigeration is required and you make the laws controlling deforestation and related damage to the environment.
posted by pracowity at 7:18 AM on July 7, 2019 [3 favorites]

About 155 trees per person.
Can't I just plant some Sargasso?

Sargassum is an algae rather than a tree - but if your implication is about the importance determining what tree gets planted and where it gets planted - then you are right to point out that the planet’s CO2 levels don’t care. If my $20 and $2 maintenance gets me one tree at the bottom of my garden but 200 somewhere tropical and poor - then let’s start in the latter place.
posted by rongorongo at 7:24 AM on July 7, 2019

If my $20 and $2 maintenance gets me one tree at the bottom of my garden but 200 somewhere tropical and poor - then let’s start in the latter place.

And here we start to see one of the perennial problems with environmentalism. What do the people in that hypothetical tropical and poor country think about your trees?
posted by Homo neanderthalensis at 7:51 AM on July 7, 2019 [6 favorites]

I got so sick of this attitude that if doing one thing won't solve all of our problems in one fell swoop then it's not worth doing. Very few problems have one single magic bullet solution.
posted by The Underpants Monster at 7:59 AM on July 7, 2019 [23 favorites]

I remember Freeman Dyson talking a while back about using trees to combat climate change. At the time I pretty much dismissed it as just old guy talk.
posted by DarkForest at 8:45 AM on July 7, 2019

Hooray! I love an Afforestation thread!

I suppose we should skip the politics of re-planting 'farmland' in the United States at the moment, as all of the reactionary forces of the Farm Bureau and a Republican adminstration are unwilling to consider that this 'farmland' (which includes thousands of square miles of former wetland forest) needs to be re-configured in a changed climate---Can we finally get rid of subsurface tile drains, y'all? Petrochemical Ag is destroying the health of communities along the Mississippi River and destroying our food system down here in the Gulf of Mexico. Have you seen the price of crab lately? those of us who eat from the ocean don't have a Farm lobby.

but like i said, those conversations aren't going anywhere in the USA for the moment, but cities are a fertile topic. There are plenty of groups in the USA to help you plant trees, which you probably shouldn't be doing just now, in the summer--so you have lots of time to plan.

If you need to start a project in your local area, there are some online tools like ITreeTools to help you advocate for funding or volunteers, or other support. If you can argue for the benefits of the Urban Canopy based on public health, or stormwater management, rather than climate alone, you can build a larger constituency.

There are local groups like Groundwork USA who are already tapped into many of these resources.

ESRI has a tool for estimating how much Urban Canopy your area (in the lower 48, sorry AK and HI) will lose in the near future, due to development, as a metric to raise awareness of the importance of trees to your local watershed, to local folks' health as mitigation for the urban heat island affect.
So "Discover your local Green Infrastructure assets"!

Some of the minds who 'invented' the concept of 'green infrastructure', before it was co-opted and changed by the Bush administration, have developed Land Image Analysis software, as well as video tutorials, to help you harness the public data of the United States to grow more trees!

But hey, Green Infrastructure needed to be co-opted by the engineers, somewhat, for it to be recognized as a valid thing by Municipal and State RFPs. There's even a certification now! check here for classes in your area.

Some cities, like Atlanta and New Orleans, have created specific 'Green Infrastructure' your local municipality to see if they have public funding for such a venture.

Of source, public funding for the public trust and public infrastructure by itself isn't enough; how do we enact the spirit of Van Jones' Green Jobs, or the Green New Deal? I know in New Orleans that we are seeking to employ ourselves to restore our urban canopy, rather than folks from out of town. In 2019, it means we need to hire many more folks of color in all arenas of environmental occupation-planning, engineering, contracting, subcontracting. Equity is a paramount concern for the "Water Management" or "Environmental" sectors into the future.

Where I am, these professions and occupations have been dominated by oil and gas and construction sectors, historically. Oil and Gas and Construction are some of the most in-equitable economic sectors of the US economy--not a lot of women or folks of color in positions of power. This is a chance to shift that power dynamic, so that everyone can be employed in this sector, at the same time we capture the carbon.

Let's hire local, hire ourselves to fix the world.
posted by eustatic at 8:49 AM on July 7, 2019 [20 favorites]

The major roadblock to this could be political: the ascendant reactionary populist right regards deforestation as a culture-war imperative, because it makes the snowflakes cry delicious salty tears. Which is why Bolsonaro is torching the Amazon and Australia is logging old-growth rainforests in between subsidising coal. Actually achieving this may involve some sort of sleight-of-hand, letting them sacrifice particularly scenic and species-rich forests for the lulz and mudkips with all the awesome chest-beating drama of a monster-truck demolition derby and, with the other hand, planting lots of unglamorous-looking plantations of carbon-sucking, oxygen-emitting plants.
posted by acb at 9:04 AM on July 7, 2019 [4 favorites]

What do the people in that hypothetical tropical and poor country think about your trees?
That is, of course, a paramount concern when planting trees anywhere (even at the bottom of my garden; ask my neighbours). But in this case, the researchers assure us, we are talking about using land that is non- urban, non agricultural and not already forested. Such land is, of course owned and valued for something everywhere. To succeed, the prospect of putting (and keeping) trees on it just has to be more attractive than the current use. Trees can create various lines of income, employment and tax revenue. So I don’t think the argument in their favour for locals is un-winnable at all.
posted by rongorongo at 9:25 AM on July 7, 2019 [1 favorite]

The biggest problem with tree planting to remove carbon from the atmosphere is that anywhere trees can grow without irrigation is almost always also a place cost effective farms can be built. And there's still a growing population eating very close to 100% of the food we produce.

On the gripping hand, a significant number of farms produce animal feed, corn for ethanol, tobacco, and we could potentially cut back all of those. I'm in favor of eradicating the ethanol subsidies, it'd be hard on the few family farmers who grow corn for ethanol, but mostly farms are owned by giant corporations so I'm not really going to worry too much about it. Of course eliminating, or even cutting down on, the firehose of money we're blasting at the rural parts of Iowa is political suicide, so no one will propose it.

However, it's essential to remember that the best way we can do carbon capture with trees isn't going to involve especially scenic looking woods or forests. You want fast growing trees planted in a carefully calculated pattern for optimal density vs. growth, and you want those trees cut down and replaced by new trees on a regular basis.

Interestingly we already have a model for doing that: paper farms. And, with paper farms, we even get the end product of the trees put into a sequestered format where the carbon won't be released back into the atmosphere.

But they're a monoculture, not very attractive, and the regular plant and harvest cycle is not one that appeals to a great many people on an emotional level; I'm not a huge fan. Old growth forest is, sadly, carbon neutral.

Trees to capture carbon have no particular aesthetic appeal and aren't really great homes for most wildlife.
posted by sotonohito at 9:36 AM on July 7, 2019 [7 favorites]

The biggest problem with tree planting to remove carbon from the atmosphere is that anywhere trees can grow without irrigation is almost always also a place cost effective farms can be built.

This is pretty clearly something the original paper addresses.
posted by ambrosen at 9:38 AM on July 7, 2019 [1 favorite]

Re: the Kevin Drum argument about the futility of planting trees ...
We have emitted about 450 gigatonnes of carbon since the start of the Industrial Revolution [...]

[I]t would take 50 or 60 years for these forests to grow to maturity. Unless we do something about actual emissions, we will have added at least 500 gigatonnes of additional carbon by then, bringing us to total emissions of about a billion gigatonnes of carbon[...] The trees would make only a small difference.
Is this for real? Drum claims 450 + 500 = 1,000,000,000, therefore sequestering 205 gigatonnes won't matter at all?

I imagine he must have meant "thousand" not "billion". If so, then we are looking at an equation where in 60 years, we could choose between having emitted a net of 950 gigatonnes of carbon, or one where we had a net of 745 or so? I know that's not going to solve global warming on its own, but it's surely nothing to sneeze at, especially if there are other benefits to having forests?
posted by rustcrumb at 10:30 AM on July 7, 2019 [1 favorite]

Planting trees is good, but so is cutting down less trees. Every suburban and rural US development starts by razing the building site to the ground, including all vegetation, building an oversized parking lot (due to weird code requirements for parking), and planting a few sad saplings here and there. 5-10 years later, the big box store or mall or office buildings whatever will be out of business, the quickly built store or strip mall or little office buildings will be looking shabby, and a new developer will raze it all to the ground again, including the tiny trees, and start over with a differen tdesign. Why not let mature trees and other vegetation stay in between? Who wants to shop or work or park your car where there is no shade? Most logging in the US is now done in smaller swaths rather than clearcutting, and some amount of mature trees stay while the logged swath recovers (and this small scale clearing/forest growth cycle can be a great thing for wildlife and other parts of the ecosystem.) So why are our urban and suburban environments essentially clear cut to produce asphalt deserts?
posted by thefool at 10:45 AM on July 7, 2019 [4 favorites]

It is possible for Silicon Valley to get rich off reforestation. Planting trees is surprisingly dangerous. Companies like DroneSeed (US) and BioCarbon Engineering (UK) are working to make tree planting faster, easier and safer. (And also, make scads of money for their investors by improving efficiencies.)
posted by rednikki at 10:57 AM on July 7, 2019

So why are our urban and suburban environments essentially clear cut to produce asphalt deserts?

Because they think trees are unnecessary and they want to minimize cost, risk, and bother. No risk of falling branches. No birds pooping on cars. No tree trimming costs. No worries about roots putting a wrinkle in the asphalt.
posted by pracowity at 11:22 AM on July 7, 2019 [3 favorites]

So, trees are needed, and this is good news, but trees alone won't solve the problem.

Why do we do this with literally every discussion?

Does anyone think one gun control measure will stop all gun violence? No, of course not, but that's the argument made every time any gun control measure is proposed.

Modern problems generally don't come with one-size-fits-all solutions. We all know this. Does anyone need a reminder at this point?
posted by scaryblackdeath at 11:23 AM on July 7, 2019 [17 favorites]

I don't understand why people are being quite so pessimistic about the potential of large scale tree planting - after all there is already more tree cover in China and India than in the early 2000s.
There are now more than 2 million sq miles of extra leaf area per year, compared with the early 2000s – a 5% increase.
posted by peacheater at 11:25 AM on July 7, 2019 [5 favorites]

I think for me the number is just so mind bogglingly huge. Can the planet even hold 1 trillion trees? (Yes, but only after a lot of thought realizing just how big the planet is)?

1 trillion.
posted by anem0ne at 12:25 PM on July 7, 2019 [2 favorites]

Per best estimates there are currently about three trillion trees on Earth. So, yup, definitely possible for there to be one trillion, and for us to add another trillion or maybe even two or three, to that total.
posted by sotonohito at 1:57 PM on July 7, 2019

From the article: “This new quantitative evaluation shows [forest] restoration isn’t just one of our climate change solutions, it is overwhelmingly the top one,” said Prof Tom Crowther at the Swiss university ETH Zürich, who led the research. “What blows my mind is the scale. I thought restoration would be in the top 10, but it is overwhelmingly more powerful than all of the other climate change solutions proposed.”

A more realistic perspective, from Zeke Hausfather on Twitter:
The new Science piece on reforestation has resulted in quite a bit of confusion. They suggest a sequestration potential of 200 GtC, but (incorrectly) suggest it would represent two-thirds of all emissions from human activities so far. This is incorrect.

Cumulative emissions to-date from land use and fossil fuels are ~640 GtC (via the @gcarbonproject), so removing 200 GtC would represent one third of historic emissions.

Similarly, sucking 200 GtC out of the atmosphere doesn't reduce atmospheric concentrations by 200 GtC, just like emitting 200 GtC doesn't increase concentrations by that much. An airborne fraction of ~50% applies to both, as both similarly affect land/ocean carbon sink behavior.

Finally, 200 GtC is a technical potential assuming every hectare of forestland on earth is increased to 100% forest cover. In practice, the economic potential will be substantially smaller, and fragmentation of ownership would make coordinated global efforts challenging.

That's not to say that reforestation is not an important mitigation strategy, just to caution that like every other climate solution it's part of a larger portfolio of strategies rather than a silver bullet.
Here's a graphical view of Canada's climate policy, assuming the national carbon price floor continues to rise by C$10/t after 2022. Land use / reforestation isn't shown - in recent years, pine beetle kill and forest fires have made Canada's forests a net carbon source rather than a carbon sink.
posted by russilwvong at 2:13 PM on July 7, 2019 [5 favorites]

“We cannot identify how much land is truly available for restoration”
Reforestation where possible on land, then, and artificial islands full of trees. Floating orchards in freshwater lakes, ash and pin oak tree farms, a plan to save Miami with a string of off-coast mangroves... we broke everything, so let's terraform.
posted by Iris Gambol at 2:47 PM on July 7, 2019 [2 favorites]

I heard that Treewoman suggests that you worry more about planting a individual trees where they have the best chance to survive. (E.g. similar to trees living nearby. Maybe not in neat rows where they're easily harvested mowed down and/or eaten by predators.)

Other'n that, they should go where they can grow. That should be an adequate ethic. One here, one there, adds up to a real forest after a while.

There's a group that already planted 15B trees since it was started in 2006. Maybe there's a branch local to yours?
posted by Twang at 3:48 PM on July 7, 2019 [1 favorite]

Branch, hehe.
posted by The Underpants Monster at 5:27 PM on July 7, 2019 [4 favorites]

The biggest problem with tree planting to remove carbon from the atmosphere is that anywhere trees can grow without irrigation is almost always also a place cost effective farms can be built. And there's still a growing population eating very close to 100% of the food we produce.

And global warming will shift where that food can be grown. Unfortunately, in order to grow food effectively, the soil must be cultivated through a process that can also take decades or longer. One of the effects of global warming will be a massive food shortage.

Anyway, I don't mean to be so doom and gloom about this stuff. We can beat global warming, but it will require everything we've got and then some. For one thing, we will have to develop technology we don't have yet that can efficiently suck carbon out of the atmosphere.

I'm not sure how many trees it takes to suck up a car's emissions, but I would be interested in knowing. I'll bet it's a lot, which means the best and easiest way to reduce future emissions is still not to use oil.
posted by xammerboy at 6:14 PM on July 7, 2019

Another kiwi planter of many trees chipping in. Many large programs ignore soil carbon sequestration - here at least NZ this is due to a previous govt (deniers) ensuring kiwi farmers could not count soil carbon in their equations. Latest govt trying to unravel this.

But Labour govt has done its first stupid thing starting the One Billion Trees program (1Bt) with the aim of sequestering large amounts of Carbon - like Crowther, this is very broad-brush\top-down\lock-in-thinking\siloed and misses a lot of fundamental science e.g.

- treating all plants or all trees as equal in C sequestration

- not addressing deep-soil\deep-time carbon pools - no sense sequestering if you're not aiming for centuries or more. With thought and careful plant care it is possible to create these deep pools but shotgun tree planting won't do it.

- not addressing that most land is already in use

- planting in the wrong place - here in NZ they've just worked out there's a rush to plant the East coast, which is drought and fire prone and threatens to dry out the few remaining streams that haven't been sucked up to make milk powder

- Forestry per-se is a big part of the problem if you plant the wrong trees. The wrong trees in the wrong place can lead to significant methane release; that paper's a good place to start. Forestry is the sales pitch as people think they understand forestry but here the harvested product must NEVER become free carbon again, which is hard with wood as it wants to rot...

- there is little addressing that stable carbon pools are those that stay undisturbed the longest. With care urban soils could be managed for very long term stability and high soil carbon storage - as they are intrinsically low from abuse they have high C capacity. Except for the most degraded agricultural soils ('e.g. US chemical monocultures) most ag soils have little extra C capacity.

I agree we cannot delay but Crowther Lab etal need the right minds in the room when they dream up stuff like like this. I remember seeing how attractive forestry problems were for people (programmers) who didn't understand biology yet were drawn like moths to a flame when they saw what they thought were 'just trees'. I imagine 'investors' will be similarly sucked in to forest investment schemes. -it's been happening here for decades!

That's rude of Crowther! AFAIK Architecture of the wood-wide web: Rhizopogon spp. genets link multiple Douglas-fir cohorts Beiler etal is the first paper to use "wood-wide web", and yet Crowther \Steidinger etal share no authors and fail to even cite Beiler.

I fully agree with happyinmotion, and mummimor:
I remember reading about a Sahara NASA-led program where they scanned the desert looking for creek junctions and then dug those and found many sighs of a temperate culture

seanpuckett - with greatest respect hemp may be 'grass' but is not a grass, ; it's not even a monocot. Different plant types live for (store carbon for) differing lengths of time. Some plant and soil fungi combinations can create very durable (centuries) forms of soil carbon, in permanently-cool deep soils.

Humanity has willingly ignored this until it (just might) be too late. And now there's the typical rush to catch up. We will have to succeed but it will be a task with many solutions, many pathways, lots of redundancy and lots of differently-aged carbon pools and with different carbon chemistries.
posted by unearthed at 12:37 AM on July 8, 2019 [7 favorites]

The Guardian article mentions, towards the end, that we currently have a net global net loss of 10 billion trees per year - about 0.3% of the total left. So any effective reforestation programme is also going to be about at least reversing that net trend.

Desertification is another phenomenon that needs to be borne in mind: we are losing a lot of potential tree planting land by this route at present - and, worse still, the process releases carbon to the atmosphere. It is something which affects most of the word's available land too. I'd recommend Allan Savory's TED talk about about how to reverse this - he points out that we have not really understood what caused desertification until recently - we could see only that rates started to rise in the last 10,000 years and that efforts to manage the problem in the last century have been largely unsuccessful. For many years it was suspected that livestock over-grazing was the cause. Savory's finding was that having livestock graze in large herds that moved from place to place reversed desertification effectively because it sped up the biological decay of the grassland before the next rains arrived: the animals defecate and urinate on the grasslands they graze on - then they move on - just as wild animals living on grasslands do. The results are worth seeing.

As with large scale tree planting, reversal of desertification can be done quite inexpensively. Savory claims that we could "revert carbon levels to pre-industrial levels; while feeding people" if this policy were to be followed on just half the world's grasslands.
posted by rongorongo at 1:28 AM on July 8, 2019 [1 favorite]


posted by steef at 8:48 AM on July 8, 2019 [3 favorites]

How much carbon does our lumber sequester? -- It's not all that much, and keeping it sequestered depends on economic conditions. (John Timmer for Ars Technica, July 7, 2019)
Carbon sequestration is generally thought of as locking carbon out of the atmosphere semi-permanently by incorporating it into rocks or forests that are then preserved. But there's a large cache of carbon in a form that's not especially permanent: the wood we use in our buildings and other structures. Some of that lumber has been in place for hundreds of years, while other bits of wood are used temporarily and then burnt or left to decay, which rapidly releases their sequestered carbon back into the atmosphere.

So it shouldn't surprise you that figuring out how much carbon ends up sequestered through our use of wood products is not a simple task. Undaunted, Craig Johnston and Volker Radeloff of the University of Wisconsin, Madison, have decided to tackle it. By viewing that carbon as a pool that's being drained and filled at the same time, they find that the total sequestered carbon is tiny—and subject to rapid changes based on political and economic factors.
The research: Global mitigation potential of carbon stored in harvested wood products (Proceedings of the National Academy of Sciences of the U.S.A.; abstract only)
posted by filthy light thief at 9:00 AM on July 8, 2019 [1 favorite]

Interesting articles filthy light thief and we'll need every tool in the box. Here's a bit more nuance to things I said above.

We don't just want any carbon, we need carbon that's locked into place for centuries to millennia. The right plants (and in association with the right soil microbiology) can get us there. We want **recalcitrant carbon**, carbon that is locked into the soil, preferably at depth where deep cold soils give further protection. Most carbon is **labile** it turns over very quickly and is held in forms\places where slight heat changes can release it. A soil carbon overview I use a lot is Large-scale sequestration of atmospheric carbon via plant roots in natural and agricultural ecosystems: why and how/

Plants are only a (small) part of the solution tho' as, carefully chosen, they can favour the right mycorrhiza (soil fungi) that will sequester large pools of recalcitrant carbon: Plant diversity increases soil microbial activity and soil carbon storage/

There are lots of different carbon-sequestering soil fungi (along with many other soil-C capable organisms) but again not all are equal carbon storers as they all produce carbon forms along a recalcitrant-labile spectrum and we want the former. One of these long-life carbon formers is Glomalin (Hiding Place for a Third of the World’s Stored Soil Carbon - USDA/). A great place to start with glomalin is Large contribution of arbuscular mycorrhizal fungi to soil carbon pools in tropical forest soils/ and follow the citation chains from there - glomalin holds many solutions to some other little problems we've created like ¹polluted soils/

Here's a simple example of the right plants, using small additions to a standard clover\grass pasture mix: Forbs differentially affect soil microbial community composition and
functions in unfertilized ryegrass-red clover leys/

At this point I know that real sustainable solutions are those that will run themselves without much human intervention (altho' we can initiate them) and are a combination of our human culture and a deep understanding of all the biologies Earth possesses.

I also know that rural land owners are very easily manipulated by simple-thinking politicians who dislike the science, complexity and nuance that will save us.

¹ Sequestration of heavy metal by glomalin-related soil protein:
Implication for water quality improvement in mangrove wetlands - I've some how got a fulltext of this paper that is not on the w3
posted by unearthed at 11:29 AM on July 8, 2019 [7 favorites]

Planting trees can help save the planet – but only if governments put people first
By Stephen Woroniecki -- Stephen Woroniecki is a doctoral candidate working on sustainability and climate change at Lund University Centre for Sustainability Studies
posted by mumimor at 6:38 AM on July 9, 2019

There's a good (but probably paywalled) perspective in the same issue of Science. Perspectives are usually written by other experts in the field and are a sign that editors really want to highlight an article they think is important. Given that I'm a bit surprised while they praise the article there's a lot emphasis on the challenges of reforestation not discussed in the paper:
The kinds of trees as well as how and where they are grown determine how and which people benefit. In some contexts, increasing tree cover can elevate fire risk, decrease water supplies, and cause crop damage by wildlife. Reforestation programs often favor single-species tree plantations over restoring native forest ecosystems. This approach can generate negative consequences for biodiversity and carbon storage (5), threaten food and land security, and exacerbate social inequities. How restored lands are governed determines how reforestation costs and benefits are distributed.
[ . . .]
[Current] forest restoration programs are largely conducted on project scales by using approaches that are neither cost effective nor designed to achieve multiple benefits and long-term sustainable outcomes
Needless not an "easy" "hiding in plain sight" way to "tackle [the] climate crisis", to quote the articles covering the story in the OP. This is same the lazy "we can only write about science if we pretend it's going to cause a major impact in the world" that contributes to the mess we're in now.

Reforestation on this scale is IMO could be considered a form of massive geoengineering that has the similar risks to ecosystems, weather patterns, unintended consequences as other geoengineering projects.

OTOH, while that might sound like a strike against it from others, coming from me it's not. I'm at the point where I am willing to see other geoengineering projects studied too, up to and including the infamous sulfate aerosols, so of course I want to see plans for reforestation aggressively pursued too. As a piece of the solution.
posted by mark k at 9:06 PM on July 9, 2019 [3 favorites]

On July 29th, the citizens of Ethiopia planted an estimated 350 million trees (about 3.5 per person) as part of a national campaign.
posted by rongorongo at 4:12 AM on August 1, 2019 [4 favorites]

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