[runarberg]

Can’t you just use the wood for something instead? I’ve seen a lot of innovative use for wood in large construction projects. For example, there was a recent proposal to replace the West Seattle bridge with a timber through arch bridge, and timber skyscrapers are apparently now a thing. This is especially true since concrete is a really polluting industry, and finding ways to use less cement is a pretty solid climate action.

[jjk166]

There simply isn't that much demand for wood. It is already used extensively as a building material, but only a tiny fraction of the world's forests are used for lumber production. Indeed lumber production doesn't even make up a large portion of trees that humans clear. For context 12 trillion trees of lumber would be enough to build 100 to 500 two story residential homes per human being on earth.

Again, this doesn't really matter since this wouldn't physically fit on the planet.

[stevage]

Not much demand? Prices for timber have skyrocketed lately, demand is enormous.

[jjk166]

The price of lumber is currently the same as it was in 2018. The price spike during the pandemic was due to reduced saw mill capacity and subsequent panic buying. At no point in time were we running low on trees.

We would need to consume timber at about 1000 times the current rate for timber demand to equal the necessary tree planting rate for carbon capture.

[runarberg]

Do you think there is any room for induced demand of timber? Like in 40 years we cut down a bunch of trees to sequester the carbon and people find new innovative things to do with the lumber, not just in construction but also in material science, packaging, etc.

I’m thinking about salt as an example. It is a by-product of many industries and cost have gone down a lot since the industrial revolution. I’m imagining that today’s salt demand is heftily induced as a result. I mean, it is cheap enough to spray on highways to melt the ice.

[MichaelZuo]

Agree, it's such a bizarre statement that their other opinions seem suspect.

[brnt]

Some say concrete should be replaced wholesale with wood (CLT). I imagine that would make a dent?

[jjk166]

Every year humans use approximately 9 Billion tons of concrete. The mass of 12 Trillion trees is approximately 1100 years worth of concrete. This much lumber would need to be used every 200 years or so.

[runarberg]

I see, so we are never going to be able to use trees to capture our current current CO2 emissions. However would it be possible to use trees (and other photosynthetic organisms) to capture our historic emissions in a mass global atmospheric cleanup efforts, after we’ve mostly gone carbon neutral? Or is that also like a 1000 year effort even if we became carbon neutral tomorrow?

[jjk166]

If we stopped emmitting CO2 tomorrow, a realistic increase in number of trees (~1 trillion trees) would take about 900 years to return to pre-industrial co2 levels. The more trees you plant, the faster it goes, but even if you cover the entire planet in forest (including places like Antarctica and the Sahara), you're still looking at centuries.

Other organisms can be used as well, but again you need to sequester the carbon.

[runarberg]

Thanks. I appreciate your answers here. This is why I love HN. Getting answers to questions on niche topics I don’t even know how to begin searching for.

[r_hoods_ghost]

Pretty much. I don't have the numbers but the phrase to always bear in mind is "fossil carbon." All that oil, gas and coal was once living bio matter (to a first approximation). Industrial civilisation has been predicated on us burning fossil carbon laid down over millions of years by earths organisms. It will take more than a few decades to remove the excess that we have pumped in, even if we reforest the earth, reduce the population and all become ascetics.

[ninju]

Of course the creation of concrete has its own environmental impact

https://psci.princeton.edu/tips/2020/11/3/cement-and-concret...

[krallja]

There isn’t enough wood used, by several orders of magnitude.