It seems incredibly practical to me. I've seen a quote for 40 dollars to plant a thousand trees. That's something like 50 billion to offset a decade of global warming? Doesn't sound so bad. Spread the cost out worldwide, 5 billion a year, split between a few big countries?

http://forestandrange.org/southernpine/magement/planting/rea...

I don't think planting trees is the biggest issue. Access to water is. More practical solution would be to fill some desert with sea water and grow plankton, kelp etc.

Deforestation is one of the reasons some deserts have spread so rapidly. trees behave as a shield to that encroachment

I recently saw a video about doing this - apparently the desert is actually a really bad option if we want to combat climate change - the core problem is that the desert currently reflects a lot of light from the sun. If we cover it with forest or whatever, then suddenly we adjust the albedo of the earth and absorb more heat, negating some of the impact. Combined with the energy need to pump (and desalinate for trees - your suggestion of kelp would presumably help there) water, etc... make it not really work.

Source: https://www.youtube.com/watch?v=lfo8XHGFAIQ

I recommend watching the video - it explains it better and goes into detail - it cites its own sources.

I assume trees are good at trapping the energy from sunlight + combining it with c02 and water to produce carbon, oxygen and more water.

So planting trees in deserts with somewhat decent access to underground water tables should help cool the planet and create a great renewable resource right?

I don't think planting trees is considered to be the unquestionably most practical solution. But it's a simple solution that people can do on their own, and it has a lot of other side benefits like habitat, shade, & proven health benefits in humans.

That’s the price of the seeds though. The cost of finding the land, digging holes, planting seeds and watering them to sustainable growth would be much higher.

Honestly if HN knows any charities focused on tree planting, let me know. Happy to donate 1k-ish if it puts 10k trees to our family’s name.

Is that just for the seedlings and not the actual labor of planting them?

I've seen quotes for parts of developing countries where planting trees would cost $100 USD per thousands trees.

See FAQ point #11: https://trees.org/faqs/

> 40 dollars to plant a thousand trees

Presumably these would be some of the cheapest trees to plant. When that space is used up but the first few billion trees, where will the next billion go? How much will that cost?

trees are only a co2 buffer, they don't make it dissappear. and trees require water, and the burn up (which puts the c02 back also)

Even if we had to replant the trees every decade, that would only be 5 billion dollars a year, forever. Trivially affordable at "world power" scale.

Lack of water is a much more real blocker, with space not far behind.

The cost of global warming and the benefits we've reaped from its cause (cheap power) are both a significant fraction of world GDP. Planting 160 trees per person would be cheap, and even easily do-able by an individual in a few weekends (though it's obviously way more efficient to hire specialists to do it en mass).

The total suitable land area needed (more than the area of the USA, by my estimate) is much more likely to be the limiting factor than the per-person difficulty.

I dislike the US prison system but perhaps we could use prisoners to do it. They could plant hundreds If not thousands within a sentence and one day return to visit the forest they planted.

I like how we instinctively turn to slavery when there's a grand project that becomes vital.

Inmates already volunteer to do forestry work including firefighting. This has been going on for decades and isn't all that controversial. Expanding to planting trees shouldn't be too difficult.

https://www.npr.org/2018/11/18/669088658/serving-time-and-fi...

All the grand projects of the past few centuries were based on it. Why change a winning strategy?

Well, we have better means for automation now. But I'm just fascinated how quickly that solution pops up in such discussions as soon as it's convenient.

I like how we instinctively characterize prisoners as slaves. Seems like it trivializes actual slavery, but I have been out of school for awhile, so the conventional wisdom is probably different now.

If you don't see labour camps as a form of modern slavery, then I'm genuinely asking you to provide the definition you've learned back at school.

Traditionally, prison labor is considered distinct from slavery for the same reason that prison is considered distinct from kidnapping and forced confinement: that it reflects just punishment for which someone is duly convicted. Whether that actually applies to most people in prison today is certainly up for debate, but to tell you'd mostly need to look at the judicial system (or society at large), not at the work camp.

One could plant that many pine saplings in a weekend with good hand tools. Mechanize it, spread the cost amongst many, I believe it wouldn’t cost, relative to what it offsetting, all that much. Land acquisition would probably be the larger obstacle.

I once worked for a short spell in a tree-planting squad in the highlands of Scotland. The seasoned planters were olympically fit and each planted around 100 saplings an hour across rough mountainside.

How hard is it to plant a tree? Especially if it's young and there is very clear guidance as to which native trees should be planted in which contexts you have available to you locally (account for full size growth and sunlight / water needs).

If over one year everyone planted 3 trees per week, and we employed a work force of people to cultivate them further, we would make a huge dent in our catastrophic risk exposure? Sure, it's seemingly impractical alongside the status quo of land distribution and use ( $$$ into develop all the land and farm humans for rent!!), but... more green will be good for the health of nearly all the living things on Earth, and at the very least give us more time to find even better solutions.

It’s cheap to plant baby trees, and baby trees are the ones that are about to go through their main carbon absorption cycle anyways.

It is not difficult but doing it without the right machinery requires back-breaking labor. It looks like this: https://www.youtube.com/watch?v=uUzeruQT8xE I did it one full weekend and I was totally exhausted. Of course, there exists machines to do that, but then you can't have every person in the world chipping in.

But planting is just the first step. If you own a growing forest it needs to be culled periodically, meaning that you cut down the worst performing 10-20% of all trees.

That video is what you consider back-breaking? I planted ten trees on my property with a mattock & shovel over the course of two weeks, removing maybe fifty gallons of clay for each hole, and while it was hard I wouldn't describe it as back-breaking. You'd also adapt to it as you got stronger...

With everybody trying to burn it, or steal it, or pour concrete over it, can be very hard.

Is an 80 years' work in any case.

For comparison, in Sweden, Finland etc there is 5-10000 trees per capita already. Adding a 1000 more per head would be easy in terms of space. So that would cover say 100M people.

But it might be part of a solution.