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Comment by onetimeuse92304 | Hacker News Reader

Trees do not affect CO2 levels, over long time. The basic reason is explained by why it is also called "carbon cycle". Plants grow, temporarily storing carbon, then die, releasing the carbon back to atmosphere either by burning or by decaying or by being consumed and literally breathed out as CO2 back.

Rather than planting a tree, you can actually help the atmosphere more by cutting a tree and building a house out of it and not letting it rot for a really long time. By cutting the tree and building the house, you are sequestering the carbon for probably longer than the tree would live (depending on what would be its future) and also making space for new trees to grow.

If you are looking to actually affect the long term outcome, you need to do one of two things:

1) stop emitting CO2

2) sequester the atmospheric CO2 somewher, for a really long time.

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Trees are great carbon sinks. Especially the ones that live for hundreds of years. If more trees get planted, then soon they’d be giant carbon sinks for hundreds of years. That’s more than enough time for artificial co2 sequestration tech to catch up with more effective permanent solutions.

Civilisation emits more new (coming from oil and coal) carbon to the atmosphere every 10 years than is contained in the entire Earth's biomass.

Even if you planted every single place on Earth that could accept a tree, you would not double Earth's biomass. If you did this and then somehow managed all those trees from dying, the only thing you would achieve is you would delay the entire proces by roughly 7 to 8 years. And if you can't prevent trees from dying or getting burned, you only get about 5 years.

From my point of view, planting trees is a huge distraction. There is absolutely no way planting trees will get us out of our problems, it is much better to start thinking about something actually productive.

Source? I think you need to check your math. To sequester all of the co2 that gets emitted per year, you’d need about 1.6 trillion new trees. This assumes no other improvements in anything. This is because 37 billion metric tons (global co2 emissions) divided by an average of 22 kg of co2 sequestered by the average tree gets us around 1.6 trillion trees.

Trees are a great co2 sink and large reforesting would result in a lot of runway, on the order of hundreds of years of runway, for technological co2 sequestration to develop further.

The word "sequester" implies that the CO2 is being removed from the cycle.

You are misusing this word, by suggesting that planted tree is a sequestered form of CO2. That's not the reality, in reality trees die or burn.

Your logic is faulty.

You see, you can bind all CO2 we emit per year with 1.6 trillion trees. True. But you can only do this ONCE, and it takes many years.

And then you are left with the Earth's landmasses all covered with trees that need to be actually sequestered (like buried deep underwater) to create space for a new batch of trees that have to be planted all over again.

Trees would be replanted as they die, and the dead trees would be used for products. It's a constant process or cycle, not a one time thing. Also, by the time you plant enough trees to cover the entire landmass hundreds of years will have already passed and by then we're sequestering co2 with technology and firing it into space or using it for something else, with large reforestation projects ongoing because it's beautiful to have trees.

From a climate concern point of view, trees as carbon sinks work.

Do you have literally any sources for your claim because what you’re saying goes against everything I’ve learned about climate change.

Google these things:

- global amount of co2 emissions per year

https://www.statista.com/statistics/276629/global-co2-emissi....

- average co2 sequestered per tree - 25-45 kg depending on species (google for estimates)

https://www.usda.gov/media/blog/2015/03/17/power-one-tree-ve...

37 billion metric tons / 25 kg = ~1.48 trillion

Amount of land available for reforestation as of 2019 is enough for 1.2 trillion native saplings.

https://www.science.org/doi/10.1126/science.aax0848

So, we plant 1.2 trillion trees for offsetting a single years worth of emissions?

It actually is closer to 5 years by my estimation, but that's pretty much it.

If you start with completely empty land, at first you will have increase in biomass, but after some time for new trees to grow you will need to have some other ones to die. The trees might keep exchanging CO2 to O2, but you will also get steady increase in emitted CO2 either through forest fires or microorganisms or animals eating and decomposing and literally breathing the CO2 back to atmosphere.

When things are in balance, forests do not actually remove any CO2 because any CO2 removed is balanced out by new CO2 emitted. Only planting a new forest on a new land binds some new CO2, and that only temporarily until the forest matures.

They offset that much co2 each year. It’s not a one time thing. Over the average tree’s lifetime, it will store 25-45 kg of co2 per year. So it’s not just a single year of co2. It would be decades to hundreds of years. Throw in renewables, fusion, nuclear, electric cars, co2 sequestration machines, etc, and it’s definitely a game changer.

Yeah, trees will only remove the CO2 from the cycle for a century or so.

That's why "invest on renewables" was right next to it on the OP. I'd invert the order, and invest on artificial capture too. But the comment is quite right.

The fact that it won't live forever doesn't change the fact that a tree pulls CO2 out of the air. Nothing lasts forever. There are no silver bullets. Don't only plant trees, but plant trees nonetheless.

That's 200 trees for every single person on the planet, each year, again and again. And they need to live long enough to become average trees, so you need to plant more than that because quite a few won't make it.

Where do you find the space for that, and the labour?!

Amount of land available for reforestation as of 2019 is enough for 1.2 trillion native saplings.

https://www.science.org/doi/10.1126/science.aax0848

We could also set aside more land for reforestation as well.

Finding labor is easy.

This is an easy problem to solve, we just need to build up the knowledge that it is possible and then execute on it. Right now most people have never even considered things this way because they’re only exposed to doomer talk whenever climate change gets discussed. :(

Room for saplings is not the same as room for average sized trees. And it's only for a single year, we'd need to do this in perpetuity.

It would probably use land that's currently in use for agriculture, in a time when huge areas of old growth rain forest are cleared to make more space for agriculture. One country deciding to turn pasture into forest would probably cause more forest to be lost in Brazil, of a type that stores _way_ more CO2 per hectare.

I think we should start with getting better at preventing and fighting huge forest fires, and to stop considering wood pellet burning as "renewable energy".

Any further focus on planting trees only distracts from real solutions, imo.

> Civilisation emits more new (coming from oil and coal) carbon to the atmosphere every 10 years than is contained in the entire Earth's biomass.

That's absolutely false. Most of the world's biomass is stored in peatlands and burning that much peat in 10 years would increase the atmospheric CO2 by hundreds of ppm very quickly - significantly more CO2 than humans have produced in our entire history combined.

For the purpose of ecology, peat is not biomass. Biomass is living things. Trees. Bugs. Fish. Microbiota. Not peat.

Why is this important is that living things form a carbon cycle of which our atmosphere is a part. Peat is sequestered for an unknown amount of time and is at the very least temporarily removed from the cycle.

With climate change, they probably won't live hundreds of years. They'll die in a drought or forest fire or flood some time in the next decades, or be cut down for firewood.

Planting a tree makes a carbon sink that lasts at least a century. During that time we can try to fix the rest of the mess.

Where did oil come from?

The oil came from small microorganisms that fell out of carbon cycle by getting themselves in places where they could not rot or get burned. The same story is behind coal, except it is not possible to generate any more coal deposits naturally.

The reason we have coal is some hundreds of millions of years ago there were huge plants that would topple but there was nothing on Eearth yet that could completely digest plant matter. So the biomass would basically stay where it fell and new plants would grow on top of dead ones. This explains the shape of coal deposits.

Some time later I think fungi evolved that could digest cellulose and any plant afterwards would rot rather than get burried. This explains why ALL coal deposits in existence are older than something like 600M years.

As I understand it, that's no longer the prevailing theory regarding coal.

what is the prevailing theory currently?

Steve Mould (a credible science YouTuber) says coal came from trees https://youtu.be/b34al8YmQSA

https://arstechnica.com/science/2016/01/why-was-most-of-the-...

> The same story is behind coal, except it is not possible to generate any more coal deposits naturally.

New coal is being made every day somewhere on the planet.

> This explains why ALL coal deposits in existence are older than something like 600M years.

Of course coal is old, because it's preceded by peat and lignite.

I think the point of the questions you were responding to is that cool is also renewable, just like trees are.

We just don't refer to it as such, because that renewability requires a really long time.

wrong, they do, but on a long timescale (million years), through hydrocarbures

of course obviously, people shouldn't extract and buy fossil fuel and all those derived products (plastics)

Most trees are cut with gas powered chain saws. Leave them up.

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