[daddylonglegs]

Most types of carbon capture technology [1] being touted are credit cards for climate change: You burn enough fuel to generate 4MJ worth of heat... Your internal combustion engine generates 1MJ worth of mechanical effort from this... You use this to propel a 2 ton vehicle... Carrying 1 person... To take part in the rat race or indulge in some consumerism. [2]

The carbon dioxide sits in the atmosphere for 50 years where it heats the planet, trashes the ecosystem and likely feeds at least as many positive feedbacks as negative - amplifying the climate change effects.

To capture this carbon you (your descendants) are going to have to: Put 4MJ of energy into the breaking the carbon-oxygen bonds... Which will take more than 4MJ of process energy and embodied energy in the capital plant... Once you have collected the diffuse CO2 from the atmosphere, which will not be free.

Our 'plan' for dealing with climate change is that we hand a burning planet to our descendants to deal with, if we can stagger to hand-off without crashing the system first. Future generations will have to be far more responsible than us, for centuries, and imagining what they will have to say makes me squirm.

[1] I am mildly optimistic about techniques that accelerate the weathering of (silicate?) rocks; and more trees will be nice. These technologies will be useful for the centuries of cleanup that will be needed, but cannot keep up with the huge rate of current emission.

[2] Yes, much of our current consumption delivers real benefits to people's lives; but much (most) of it doesn't. The point of my analogy is that the sheer wastefulness of the present excess will be paid for in the future at far greater cost and is being spent on such trivial or actively harmful goals.

[gpt5]

Genuine question - if CO2 half life in the atmosphere is less than 50 years, why are we so concerned about it? Wouldn’t the problem solve itself given that we are both reaching peak consumption of fossil fuels and that they are expected to deplete with the next century?

In other words, wouldn’t the co2 concentration go down naturally within the next 100 years even if we let thing run naturally?

[pjerem]

Because if it’s somewhat true to say that stopping CO2 emissions would rapidly pause climate change, there is no short term « reverse » (in hundreds of years) of the climate.

We are in such a situation that every +0.01°C increase in global warming is gained more or less indefinitely.

The only thing we can do is stopping net emissions and learn to live with the climate as it is when we achieve this.

We really don’t care a lot about concentrations going down in the next centuries because by the time it happens, the harm would be done already for multiple centuries.

We are really facing today, 50°C in summer and devastating events, for our generation and our kids. This precise battle is already lost but we must fight for it to not be even more dramatic.

[daddylonglegs]

50 years was my (over optimistic) estimate of how long the CO2 would be left in the atmosphere before being sequestered by one of the carbon removal technologies being touted. In reality it's going to take centuries for our descendants to stabilise the climate - and I'm still being optimistic.

[lutorm]

On short time scales, the oceans take up a lot of CO2 because there's an equilibrium with the atmosphere. However, increased acidification of the oceans is bad on its own, and this buffering hurts when you try to take the CO2 out of the atmosphere since then the oceans will turn into a net contributor.

[malloryerik]

It looks as though those numbers are mistaken.

https://blogs.edf.org/climate411/2008/02/26/ghg_lifetimes/

[gpt5]

This article seems to conflate "Time it takes for 50% of the CO2 increase to be removed from the atmosphere" with "time it takes a specific molecule that was released to the atmosphere to be removed".

The former is more relevant to the discussion, and is stated as ~30 years.

[peter303]

CO2 half life is 5,000 years. Methane is 50 years.