Every time an article on this topic comes up, I read the same responses in the comments, here or on Reddit.
Yes, it's cheaper not to emit than it is to reclaim, but how does this comment contribute to the solution? Even if everybody stopped emitting CO2 today, we still need to remove many Gigatons of CO2 from the atmosphere to save the planet. Planting trees is cheap and is PART of the solution.
Similarly, every time an article about direct air capture (DAC) comes up, somebody complains that we should be planting trees instead. This is ALSO a very unhelpful comment, because in truth we need to be doing both DAC and planting trees. Even if we reforested all the depleted forests of the world, there would still be gigatons of CO2 to remove.
The answer to every proposed solution to climate change is not whether "this or that", it is "this AND that". We need to be doing everything: reforest, DAC, wind, solar, nuclear, synthetic meats, etc. The whole kit.
Not to mention each solution has other benefits. Expanding swampland is a carbon sink and helps absorb storms & floodwaters. DAC is a carbon sink and paves the way to ultrapure synthetic designer fuel. Wind & solar save emissions, and improve air quality near human habitation. On and on. As far as I see it, they are all virtuous technologies, and their relationship with carbon is just one more reason.
So, to offset his carbon emissions, American must plant 150 trees a year, ensure that they grow for at least 10 years, and then ensure that the CO2 captured by them doesn’t get rereleased. This means that we need space for at least 3 trillion trees, which is three times the space available, based on the figure in your link. Ensuring that the CO2 doesn’t get rereleased means that all that lumber needs to be buried or sunk, since this is way more lumber than the humanity actually uses productively. Additionally, this would mean doing heavy industrial management of all this immense forest area to cut and bury all these hundreds of billions of trees a year. This would require digging huge pits, transporting lots of heavy material to them, at extra emissions. And that’s for American emission only, which are only a fraction of global emissions. And of course we ignore the question why would you want to bury all this wood while keeping digging out all the fossils, when you could be using the same wood to generate energy instead.
So no, while this might work to pacify the conscience of an individual, it makes absolutely no sense to do it at scale.
Actually, if the trees are burned or otherwise re-release their carbon, the subsequent re-planting will take care of re-re-capturing that carbon. If any of the trees die or are cut down, a new one can be planted in its place. If it still living and thriving, it should be naturally left alone.
Also, for ten years, 327 million Americans each planting 1.5k trees comes out to half a trillion trees. The link in my blog says there is room for 1.2 trillion trees to be planted, so the math works out.
When the trees die, won't the carbon be re-introduced to the atmosphere over time via microbial decomposition of the wood? That is, once the microbes that eat the trees die, they'll be eaten by something that is eventually eaten by something on the surface, thus releasing the carbon sequestered by the tree.
How about we turn them into houses or furniture. Timber used in construction can last for a very long time, all the while keeping it's carbon locked up.
Even when it finally decomposes through rot or consumption a lot of the carbon is kept out of the atmosphere, ending up in the food chain fed by the organisms that consume it.
Plant a tree now, in 200 years it may be part of your great great great grandchildren.
Even when it finally decomposes through rot or consumption a lot of the carbon is kept out of the atmosphere, ending up in the food chain fed by the organisms that consume it.
No, not a lot. In fact, it’s practically nothing, compared to the mass of trees. Think about it: are you using the mass of 150 adult trees annually for buildings? Are you sequestering much of it in your body? Not even close. Today America consumes less than a half of a single adult tree per capita per year.
The carbon is only sequestered when the trees are alive or when they are buried or sunk. If you don’t bury and only have space for a decade of tree planting, you are at best going to delay the climate change by a decade, which is not nothing, but won’t change much. And, of course, we ignore things like albedo changes due to more forestation which could offset a big part of gain.
Yes, that could happen. Replacing the dead tree with a seedling will re-capture that carbon and return to a net-zero atmospheric carbon balance.
Also, there are many situations where a net-negative amount of carbon could be released into the atmosphere: the tree could be used as lumber to build something, thus not decomposing. Or it could be partially or fully buried, sequestering some or most of the carbon in the soil.
Using it as lumber will only extend the time period when the carbon is sequestered, but won’t sequester it permanently. You need to bury it for that, and bury it deep enough so that it doesn’t decompose.
More importantly, the actual lumber consumption is trivial. America consumes half of a single tree per capita annually[1]. Even if you assume that this half of a single tree gets sequestered permanently (which is not realistic), that’s a far, far cry from 150 trees yearly.
Really, this is all so silly: if you can grow so much biomass to offset all carbon emissions, why wouldn’t you burn that biomass instead of burning fossils and burying the biomass? It makes no sense, like most of the feel-good green plans.
Why are you fixated on permanently sequestering the carbon? As soon as a tree dies, all you need to do is replace it by replanting the tree. It doesn't matter if the tree's carbon is immediately released in the atmosphere (by burning) or it happens after hundreds of years. The new tree will re-sequester the dead tree's carbon.
Also, if a tree dies, it frees up space for another tree. So in effect, as long as you keep those 1.2T trees growing (and replace any dead ones promptly), you will keep that carbon sequestered.
> Really, this is all so silly... It makes no sense, like most of the feel-good green plans.
At this point, it seems like you're just dismissing the idea. Feel free to do so, but you haven't provided any reason why it won't work.
> Why are you fixated on permanently sequestering the carbon? As soon as a tree dies, all you need to do is replace it by replanting the tree. It doesn't matter if the tree's carbon is immediately released in the atmosphere (by burning) or it happens after hundreds of years. The new tree will re-sequester the dead tree's carbon.
Because a solution that can only possibly delay the climate change by a decade or two with extreme change to global ecosystems by immense program of forestation is no solution at all. Seriously, what’s the point of doing this, if it require extreme global efforts, and will only make marginal difference? It is much more cost efficient to simply replace emissions with (also rather inefficient) solar and wind, not to mention nuclear power, instead of offsetting them by planting trees, which has no chance of having any effect other than delaying the climate change by a few decades theoretically, and a few years in practice.
The question rather is, why are you so hung up on the idea of planting trees, if it’s not going to make any difference?
> Also, if a tree dies, it frees up space for another tree. So in effect, as long as you keep those 1.2T trees growing (and replace any dead ones promptly), you will keep that carbon sequestered.
Indeed, these 1.2T live trees will sequester the carbon. I do not question that. What I question is the point of doing that if you keep emitting carbon: this will only delay the climate change by a few years, because after you use up all available space and grow these 1.2T trees to maturity, you won’t be able to capture any extra carbon: all carbon captured by the trees will be offset by the carbon emitted by decaying dead trees (or huge forest fires, which are inevitable if you don’t remove fuel from these huge foerests), unless of course you bury them.
> Feel free to do so, but you haven't provided any reason why it won't work.
No, I did, you’re just ignoring it. Again, to recapitulate: planting trees will not offset carbon dioxide emissions unless you take on extreme effort to bury these immense amounts of lumber (which would also be stupid if you keep removing more fossils from the ground and burning them). Planting trees will only delay these emissions, by the length of time that is relatively trivial compared to extreme effort necessary, and insane amounts of ecosystems destroyed. Planting 1.2T trees would destroy so many ecosystems that it would be more ecological to simply do nothing.
Planting trees to offset carbon dioxide emissions from fossils is like putting a yoghurt cup under leaking drain pipe. It will work for a while, until the cup overflows, at which point you’re back to square one. You can then replace cup and pour out water in some other drain (that is, bury the lumber), but that’s stupid, because the whole point of a drain is to pour waste water into it, and if it is leaking, you should fix the leak instead of using some silly cup-to-other-drain scheme. Similarly, planting trees will only delay the inevitable, and when the cup overflows, that is, the tree dies, you need to figure out some other way to sequester the dead tree.
> Because a solution that can only possibly delay the climate change by a decade or two with extreme change to global ecosystems by immense program of forestation is no solution at all.
> Indeed, these 1.2T live trees will sequester the carbon. I do not question that.
It seems we agree that as long as these 1.2T trees are living (and any ones that die are replaced), the carbon will be sequestered. As long as humanity can keep on doing that, the delay will be... indefinite. Are we in agreement on that point?
With the leaky pipe analogy, it seems you are worried we'll run out of room to put dead trees. Indeed, burying them is a great idea, and that can be combined with Hügelkultur technique to produce better growing conditions for other plants, including... more trees.
As far as some of the other concerns you raise: the Trees.org organization can have a tree planted for $0.10 (by people who are happy to plant it and take care of it). By that measure, it seems this method is the least expensive (if we judge effort by the amount it costs) and least extreme of all. Will Trees.org be able to scale to 1.2T trees? It's hard to say. They've planted 155M trees so far, so they need to scale by a factor of ~10000x. It will certainly be hard, but it seems to be possible: we have room for them in places where trees previously grew (see the link to the study where the 1.2T number comes from). Recently, India planted 50M trees in one day; a startup has a goal to plant 500B trees by 2050 (if they have two equally-capable competitors, the 1.2T quota can be met before then).
What ecosystems will be destroyed by planting trees? Currently deforested areas? That seems hard to believe.
I view any carbon sequestration efforts to be a partial stop-gap effort until the world becomes mostly electrified and using renewable/nuclear energy. I am for all kinds of carbon sequestration efforts, but as a consumer, I would like them to be relatively inexpensive, and not have an unknown side effect. Planting trees meet both these requirements.
> It seems we agree that as long as these 1.2T trees are living (and any ones that die are replaced), the carbon will be sequestered. As long as humanity can keep on doing that, the delay will be... indefinite. Are we in agreement on that point?
Yes, as long as there’s a cup under leaking pipe, the amount of leak equivalent to the volume of the cup is sequestered. When the cup is full and starts overflowing (I.e. your trees start to die) you have to figure out where to contain the overflow. If you do nothing, it will simply spill on the floor (I.e. dying trees will decompose), which puts you back on the square one.
> With the leaky pipe analogy, it seems you are worried we'll run out of room to put dead trees. Indeed, burying them is a great idea, and that can be combined with Hügelkultur technique to produce better growing conditions for other plants, including... more trees.
Somewhat, but not quite. The real concerns is that burying trees while you keep extracting fossils is absolutely bonkers idea.
Burying trees would make sense (though not necessarily be most cost effective way to do so) in the future world where we no longer extract fossils. Then, growing trees and burying them would (extremely slowly, and at a huge ecological cost) bring us back to previous CO2 level before industrial revolution. If you keep extracting coal from the ground, however, burying trees is insanely stupid and wasteful thing to do, because it would be offsetting the fossil emissions by literally putting the fossils back into the ground. Why go through all the motions with planting trillions of trees, if you could simply not extract the fossils in the first place?
> I view any carbon sequestration efforts to be a partial stop-gap effort until the world becomes mostly electrified and using renewable/nuclear energy.
Look, if you don’t bury trees, all you do is introduce slight delay in the system. If you want to use the trees as a stop gap, then it makes much more sense to use the trees as a biomass, that is, burn them instead. That way, you’ll actually in fact be carbon-neutral.
There are twenty times that many people on Earth. You would have to compactify the wood for building materials, or something similar, to properly sequester. I suggest iron seeding the equatorial pacific as cheaper and more scalable.
Americans produce a disproportionate amount of CO2 due to their lifestyle. So you don't need to plant twenty times that amount of trees to sequester manmade CO2; only 2.4x.
Also, as long as you replace any trees that die with seedlings, you don't need to worry about what happens to the dead wood.
This method comes out to a cost of $6.70/ton sequestered. Other methods can cost many multiples of this amount. Do you have any estimates for iron seeding of the equatorial Pacific?
US emits only 15% of global carbon dioxide. If you plant 2.4x trees, you’ll only offset 40% of global emissions. For 2.4x to cover global emissions, global emissions would have to shrink by 60%. If US emissions were reduced by that much, it would put US emissions per capita below present day Belarus and Bulgaria.
> Also, as long as you replace any trees that die with seedlings, you don't need to worry about what happens to the dead wood.
You do, though. If the wood decomposes, all the CO2 is released back to atmosphere, which puts you back at square one.
Is this true? This is something I question a lot. Intuition tells me that the greenhouse effect of CO2 and other gasses determines derivative of climate change, but its often presented like it sets the absolute average temperature.
That is, if we stopped producing CO2 completely back to pre-industrial levels (somehow), would we expect the globe to get warmer? Or are both statements true because excess CO2 naturally leaves the atmosphere into space + gets absorbed into the ocean?
Part of the problem with climate change is that some of the effects are self-sustaining. For example, snow and ice reflect light back into space. If the temperature increases then more of the ice melts, so more light is absorbed by the earth which raises the temperature.
Then even if you get rid of the carbon, the temperature stays higher because the ice is gone and is no longer reflecting light back into space. And the ice is from the last ice age, it doesn't just refreeze on its own -- especially now that the temperature is higher.
Meanwhile with higher temperatures there are more areas of drought, which means less vegetation grows there, which means those areas can absorb less carbon. And that too is sticky. If the temperature stays higher then there continue to be droughts and less vegetation.
What this means is that we need to stop emitting carbon ASAP, and then on top of that ultimately do something to reverse the effects and actively work to get the temperature back down to where it was, because it may not be able to fix itself.
We think of the Earth as a self-regulating system, but that isn't because it's stable, it's because it's adaptive. Earth's temperatures have been higher than this and still sustained life, but none of that life was humans, and the previous changes were accompanied by mass extinctions.
> Then even if you get rid of the carbon, the temperature stays higher because the ice is gone and is no longer reflecting light back into space. And the ice is from the last ice age, it doesn't just refreeze on its own -- especially now that the temperature is higher.
Check the historical data on CO₂ levels from antarctic ice. It correlates perfectly with the ice ages (we had samples of ~400K years covering 3 previous), and guess what, we are now on the brink of a next one.
Yes, it's cheaper not to emit than it is to reclaim, but how does this comment contribute to the solution? Even if everybody stopped emitting CO2 today, we still need to remove many Gigatons of CO2 from the atmosphere to save the planet. Planting trees is cheap and is PART of the solution.
Similarly, every time an article about direct air capture (DAC) comes up, somebody complains that we should be planting trees instead. This is ALSO a very unhelpful comment, because in truth we need to be doing both DAC and planting trees. Even if we reforested all the depleted forests of the world, there would still be gigatons of CO2 to remove.
The answer to every proposed solution to climate change is not whether "this or that", it is "this AND that". We need to be doing everything: reforest, DAC, wind, solar, nuclear, synthetic meats, etc. The whole kit.