[adamlett]

The article didn't cite IEA making an argument or even presenting any facts; rather, it reported an assertion that carbon capture isn't enough.

Maybe we read different articles, because I distinctly remember reading in the article that the energy cost of CO2 capture to achieve status quo using current technology would require more energy than the world is currently producing (fact), which means the solution is unrealistic (argument).

The number one argument against this kind of doomerism is that we don't know what we don't know

If that's the number one argument, I appreciate that you don't go on to cite number two, and three, because those would have to be incredibly weak arguments.

but perhaps some technological breakthrough (genetically engineered trees? dense organic materials? who knows?) could work as soon as it is discovered.

It's also within the realm of possibilities that aliens will descend and use their superior technology to restore the CO2 levels in the atmosphere. But I would advice against a plan that could only succeed if this were to happen.

[kragen]

no, it said it would require more electrical energy than the world is currently consuming; world marketed energy consumption is several times higher

specifically what it says is (https://iea.blob.core.windows.net/assets/7a4b0c4e-d78c-4a8e-... p. 95)

> If oil and natural gas consumption were to evolve as in the STEPS (i.e. with 97 mb/d oil and 4 200 bcm gas consumption in 2050), this would require 32 Gt CO2 of CCUS by 2050, including 23 Gt CO2 of DAC, to achieve net zero emissions in 2050 and limit the temperature rise to 1.5 °C. 8 The DAC would require around 26 000 TWh of electricity to operate, more than global electricity demand in 2022.

26000 terawatt hours is 94 exajoules; presumably this means per year, so that's 3.0 terawatts. https://yearbook.enerdata.net/total-energy/world-consumption... shows current world energy consumption at over 14000 million tonnes of oil equivalent per year; a toe is conventionally ten billion international-table calories, 41.868 gigajoules, so that's over 580 exajoules per year, over 18 terawatts

so it would only require 16% of current world energy production, even with today's primitive technology (but that is indeed more than current world electricity consumption)

you may also notice a rapid upward trend in that graph of world energy consumption; if that continues then by 02050 the contemplated amount will be about 10% of world marketed energy consumption

but, because i've analyzed the fundamentals, i expect that energy growth to accelerate dramatically rather than continuing the same trend (see my other comments) and to shift dramatically toward electrification

presumably also efficiency will improve if the humans scale up atmospheric carbon capture by the proposed three orders of magnitude; the inherent entropic cost is quite low