Itsumishi

Itsumishi t1_jdt4mx6 wrote

Peaceful has nothing to do with disruptive though. Disruptive is literally the point of a protest. If its not disruptive it isn't a protest.

People standing on footpaths/roads with signs: disrupting pedestrians/traffic.

Boycotting a company: disrupting sales.

Standing outside a building chanting: disrupting people's access to employment or generally being noisy and disrupting their work.

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Itsumishi t1_jdflgn0 wrote

Sequestering carbon from the air is only a small element in this particular trial (and to be honest I suspect that's a journalistic error).

The bulk of carbon emissions in the manufacture of concrete come from the processes which occur during the creation of cement. There's two elements to this:

  • Current methods of creating cement involve heating limestone and clay to around 1400 degrees Celsius. Its hard to hit these temperatures without large inputs of fossil fuels.
  • The chemical process which occurs within the limestone during this baking releases A LOT of CO2. (This is the most carbon intensive bit).

So to achieve lower carbon intensity, we need new methods of producing concrete that use significantly less cement (which is how this trial aims to achieve the bulk of its CO2 reductions); and/or we can capture some of the CO2 from the limestone and embed the carbon back into the concrete.

Pulling it from the air does seem incredibly inefficient when the concentrations will be much higher in the exhaust and waste gasses than the atmosphere. This is where I think the journalistic error occurs. The article says they'll use the AirCapture technology - but I suspect they'll use that technology within a closed system - not just pulling it from the nearby atmosphere.

And yeah - it still won't be carbon neutral, but a significant reduction in a very carbon intensive process is still better than not doing it.

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Itsumishi t1_jdfjx2p wrote

I'll assume you meant "underestimate" regarding the expense, and on that I'd just say new technologies are always expensive. The point of pilots projects etc will be to find methods which can be made cost-effective.

On the "how much carbon it actually takes to make" comment... well its not low-carbon if it takes lots of carbon - so that doesn't make any sense.

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Itsumishi t1_jdf0n6z wrote

I strongly disagree.

Firstly, I suspect you vastly underestimate how carbon intensive concrete is. We absolutely need to figure out how to drastically reduce the carbon intensity of concrete and/or drastically reduce how much we use of it (almost certainly both). But even if we drastically reduce how much we use its naive to think we can stop using it.

Secondly, carbon offsets can help slow climate change but it can't solve it. Planting trees is great. We should absolutely be reforesting everywhere we can. But a forest is only a useful carbon sink until it gets cut down, or burns in a forest fire at which point almost all the carbon stored in it is released back into the atmosphere. Forests are part of the natural atmospheric carbon lifecycle that is in constant fluctuation.

The idea that we can burn fossil fuels that hold carbon that has been stored in a stable condition for millions of years and offset it by planting a forest which then may be cut down or burnt out in 100 years or a 1000 years is deeply flawed.

But still we need to do it because we need to buy as much time as possible.

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Itsumishi t1_jd9p1xi wrote

It also sounds like the vast bulk of the CO2 reduction comes not from the capture of carbon from the air, but changing the chemical composition of the concrete (using significantly less cement). The downside to their approach is the concrete must be baked on site.

Not to say this is a bad approach, there are plenty of uses for precast concrete, but it also makes this process useless for any concrete which needs to be poured in-situ and allowed to cure (eg footpaths, building slabs, etc.).

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