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Comment by ValleyOfTheMtns | Hacker News Reader

I think all these comments about wood eventually releasing the carbon back into the atmosphere are missing the point. We don't need to capture it forever, we just need to get the ratio between carbon output and input under control in the next couple of decades. That should give us enough time to come up with longer term and sustainable ways of our planet... until we encounter the next problem, and so on.

"Solutions" don't have to be perfect forever. They just need to work long enough till better solutions are discovered.

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Additionally, if you permanently dedicate 1 acre of land to growing trees, then an acre of trees' worth of wood is permanently captured - though the individual trees may die and rot, more will take their place.

Or use it to build homes, which still keeps it out of the atmosphere

The only problem is that we don't have nearly enough space for that.

An acre of trees stores ~393 tonnes of carbon dioxide permanently (in Vermont anyway, other areas probably vary a lot) [1]

Humans generate ~40 Gtonnes of CO2 a year. That means we need to be adding ~100 million acres of trees every year to capture that. There's currently 4 billion hectares of forest cover - that's around 10 billion acres.

If we replanted every area which has seen deforestation since 1990 we'd get another 400 million acres, or 4 years of emissions. After that, we're fighting an uphill battle. Forests currently cover 31% of the earth. 29% of that surface is desert, 3% is urban areas and 10% is covered in ice. To keep on top of emissions we'd need to add 0.3% of the total each year globally, or 1.2% of the land which could actually grow trees.

That might be doable in 5 years, but 10 years? 15 years? 30 years?

Re-forestation may be part of the solution, but it can't be the only part.

[1] (PDF}: http://fpr.vermont.gov/sites/fpr/files/Forest_and_Forestry/T...

[2]: http://www.earth-policy.org/?/indicators/C56/

There is a lot more area in the ocean and seaweed grows very quickly. Perhaps we could even accelerate the sequestration by building large seaweed farms over the deep ocean, then sinking the seaweed once it grows large enough, & repeat.

I think this is going to have to happen for bio capture to work at all. We need land for food, and we'll need increasingly more of it in the next decade thanks to overfishing, and population growth

And if we could forest up some places where there's no forest at the moment, a large fraction of that carbon would be tied up there basically as long as that forest stays up.

For the most part we have been doing that for decades. The US has a lot more forests now that 100 years ago (the height of logging).

It is hard to know for sure, but there is reason to believe we have more trees than even 1000 years ago. We are not allowing forest fires to clean out the dead trees which allows them to build up. This is a negative, regular forest fires burn colder and leave a lot of charcoal in the soil, while the less regular forest fires burn hotter and so release that carbon back into the atmosphere.

So I didn't believe this statement (eg: more trees than 100 years ago), bc I'm the skeptical sort. You're right though. I looked at "US Forest Resource Facts..." page 8 and the numbers are higher for millions of acres across different types. https://www.fia.fs.fed.us/library/brochures/docs/2012/Forest...

You could also just bury it. That’s effectively putting coal back into the ground.

Wood is not dense enough for this to be cost effective.

You could burn it – the ash from burning a tree takes up only a fraction of the original volume.

Don’t know if this is sarcasm, but burning the wood releases most of the carbon dioxide back into the air. The ash is just the unburnt carbon residue and other leftovers.

Yes, it was a joke. Sorry for that.

Jokes aside, you could partially burn it, into charcoal, then grind down the charcoal, soak it in urea, and mix it with soil. The charcoal bits remain stable in soil for quite a long time, and helps retain plant nutrients.

If a woodpile isn't dense enough, then surely building homes and furniture out of wood isn't dense enough either.

Can you think of a better way to store carbon!

Not very dense compared to the cost of digging a big hole in the ground with Caterpillars and the number of truck loads of pellets you would need to bring in. This is all assuming that just covering the wood over with dirt is enough to keep it sequestered, a big pile of biomass could start emitting methane.

> Can you think of a better way to store carbon!

BECCS like they referred to in the article.

Building with it is a lot more effective as there's economic incentive in preventing it from decaying back to base elements

Good point.

I have a better idea. Leave the coal in the ground. You get the same result with literally no work!

Way too reasonable, it'll never happen.

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