Hacker News Reader

Comment by onetimeuse92304 | Hacker News Reader

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.

View on HN

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.

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.

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.

Reply on news.ycombinator.com