Hacker News Reader

Comment by ktzar | Hacker News Reader

Plant trees. Chop trees. Build stuff. Bury wood. Repeat.

Note: it doesn't mean keep burning gas at the same time.

My favourite approach is to make biochar. You heat the wood in an oxygen free environment and so can control the amount of hydrocarbons you extract. The carbon left over is fairly inert and so relatively easy to store long term. You can get enough hydrocarbon out of the process to pay for it.

If we redirected the bulk of our wood waste through a process like that - rather than it all being burnt (and so releasing all of the carbon in the wood) - we could probably sequester a few percent of global emissions.

Yeah I never understood why this wasn't more talked about.

I suppose that leftover "char" is just a little to close to coal for everyone's comfort. This is how charcoal is made, after all.

Its also a large component of terra preta. I think you could sell it as soil amendment and flip the perception on its head.

Honestly, if you can make material that's soil-like enough out of things that would otherwise be process waste, it'd be a handy way to directly combat rising sea levels. Just dump it somewhere and reclaim the land.

there is a natural gas variant of that where instead of using steam in the steam reformation process to generate hydrogen and CO2 you use more of the energy contained in the gas to cook it off into atomic carbon and hydrogen. you can then bury the carbon.

I think it would be fabolous if you could use up all the natural gas that way.

If you want to know more Google "natural gas pyrolysis".

Depends on how demand plays out. It’s possible China will oversupply green hydrogen, leaving blue hydrogen a stranded asset. I do wish hydrogen were a bigger part of the conversation today, and I think down-only emissions policy makes balancing supply and demand for emerging resources simply too hard. The $3/kg subsidy in the IRA would’ve gone a lot further if applied to grey hydrogen.

blue hydrogen is an abomination. I don't count pyrolysis derived hydrogen as blue because I can actually see some chance that the carbon gets sequestered. The pessemist in me sees the resulting carbon being sold to coal plants tho :P

That said hydrogen as a direct fuel replacement for individual transportation is something I am very much against. I simply see that we will need hydrogen for some applications but most have nothing to do with transportation whatsoever.

Yeah, this is pretty much the only solution. The only step I'd add is "make charcoal, bury charcoal". That ultimately releases H2O back to the ecosystem and you only bury the carbon.

As a bonus, it's an exothermic process, so you could recapture some of that energy to make electricity.

If you are worried about rising sea levels, why try to release the H2O back into the ecosystem?

That's...not how this works at all. Is this a joke?

No, it's not a joke.

Please explain this to me.

The rising sea levels aren't about more water being in the environment, it's about more water being in liquid form rather than stored in solid form in glaciers on land.

The small amount of water being in a tree trunk vs released back into the atmosphere isn't even close to registering.

But enough water does matter.

By the argument of insignificance, all North American CO2 emissions from 2024 will not matter.

Use actual evidence for your argument. You claimed ignorance, why should I believe anything you say?

The water cycle is much faster than the carbon cycle, so that makes very little difference.

But even if it didn't work like that, rising sea levels are only one of many different impacts of increased CO2 in the atmosphere.

Couldn't you just bury the wood? Ala Hugelkultur

You could but biological processes are liable to turn it partially into outright methane or a peat bog, which can emit methane.

note that methane is a far more potent greenhouse gas than carbon dioxide

That’s basically LARPing the Carboniferous epoch that buried most of the stuff in the first place.

According to the IPCC, to meet the 1.5 degree C target we need to be doing 6 GtCO2 of carbon dioxide removal per year by 2050.

It would be very difficult to reach that scale with reforestation and afforestation along in the next 27 years.

Plus, if you simply bury wood it will be broken down over time and release methane. No one has yet developed a scalable way to bury large quantities of wood and keep them from decomposing (startups/researchers are starting to work in this area).

The breakdown of wood a few feet beneath the surface is actually extremely slow.

If converted to charcoal ("biochar") through pyrolisis first it's much better, and won't release methane or CO2 (and enriches soil)

The bigger issue would be the logistics, and the amount of CO2 emissions simply involved in processing and burying it.

We are going past 1.5C.

That being said, the way you do this isn't specifically with reforestation, rather, this needs to be tree farming with fast growing trees. Perhaps even geneticly engineering trees for this specific purpose.

Ok - carbon dioxide removal is going to be needed to meet to the 2 degree C target too.

Sure, you can reforest or afforest with whatever trees you want. It certainly will help but won't solve the issue alone.

I'm not an expert, but presumably you need to bury wood in a sterile place so that it doesn't get eaten by bugs/microbes and turned back into greenhouse gases?

Bury in a dry place, or under water without much oxygen. Mines could work in both cases. Basically filling up coal mines with coal again.

So, transport the wood emitting some GHG doing it. No problems with that plan whatsoever. ;)

Actually mines tend to get wet and require serious drainage (pumps) to exploit. They're only dry for the moment, over time they will become waterlogged.

the greenhouse gases emitted by any conceivable transportation range are an order of magnitude less than those captured

please do the math instead of just posting bullshit without any regard to whether it is true or false

you're right about the mines tho

Some of it will turn into gases. Some will turn into those bugs and microbes and other forms of biomass.

> Some of it will turn into gases.

Yeah, and this is definitely bad.

> Some will turn into those bugs and microbes and other forms of biomass.

This is the part I'm not sure about. Does this decrease the amount of CO2 in the atmosphere enough to counter said increase in greenhouse gases?

After burying wood you are growing more wood, so yeah, as long as you are using land that wasn't forested before you are net negative

There is a huge movement in my country to entirely ban ikea from the country. It would be as usefull as shutting down all the nuclear powerplants.

What is the argument here?

They say that there is no biodiversity in forests made for wood harvest.

I suspect that other options aren't quite better than Ikea

Much, MUCH worse.

I have wondered if, on a net scale, burying said wood (in the form of chips or sawdust) in desert regions would actually net out as net-negative for CO2. Add organic matter back into the mostly sterile soils, increase moisture retention, and once a certain % of soil organic matter is restored, in turn plant trees or perennial crops back into that locale.

Trees require more time and land to capture a given amount of carbon compared to direct air capture.

The UK government is adopting a slight variant of this schema that turns it from net-neutral to net positive: have somebody else do the chopping, buy the already chopped wood, prevent the wood you bought from turning into emissions. Now you're emitting negative carbon/s.

Reply on news.ycombinator.com